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Main
Date: 08 Oct 2007 15:03:06
From:
Subject: Oldest use of tire gauges on bicycles?
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I'm wondering when tire gauges became widely used for bicycles, which
is an awfully vague question.
After all, Frank Krygowski has pointed out that tire gauges may not be
all that widely used even today.
So I'm just looking for early references to bicyclists using tire
gauges, recommended bicycle air pressures, pros using tire gauges, or
bike catalogues trying to sell tire gauges.
I got absolutely nowhere trying to find ancient Presta valve tire
gauges. Everything around 1900 seems to be Schrader. Indeed, most of
the antique gauges were made by Schader.
Ebay turned out to have lots of old tire gauges with pictures. The
dates are iffy, since they often mention two or three patents from
1893 to 1923.
The old gauges seem to come in two ranges, 10-50 psi for balloon tires
versus 20-120 psi for more modern-style tires. As far as I can tell,
both kinds of tires meant car tires.
I grabbed these pictures from auctions:
1909 Schrader pencil tire gauge and case:
http://i21.tinypic.com/5xsgba.jpg
1911 U.S. Gauge Company dial gauge to 50 psi marked for balloon tires:
http://i21.tinypic.com/149cq2o.jpg
Early Schrader 10-50 psi and Wein 20-120 psi pencil gauges:
http://i20.tinypic.com/2eoy9me.jpg
An early Schrader, at least 30-110 psi:
http://i23.tinypic.com/11vk80k.jpg
Here's a full-page 1926 Schrader tire gauge ad from the Saturday
Evening Post:
http://i21.tinypic.com/1jt5cl.jpg
As a sidelight, Wikipedia suggests that we may be fooling ourselves on
some gauges:
"The accuracy of a typical mechanical gauge as shown is +/- 3 PSI.
Higher accuracy gauges with +/- 1 PSI accuracy can also be obtained."
http://en.wikipedia.org/wiki/Tire-pressure_gauge
And for those who wonder about low-pressure motorcycle trials tire
gauges, here's one from the early 1970's:
http://i21.tinypic.com/15rlis4.jpg
These low-pressure 0-20 psi gauges are popular nowadays for inflating
huge low-pressure ATV tires.
Drat! Now I'm wondering about the earliest use of tension gauges for
bicycle, motorcycle, or car spokes! Jobst shows one in "The Bicycle
Wheel" in 1981.
Cheers,
Carl Fogel
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Date: 11 Oct 2007 03:47:04
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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Carl Fogel writes:
> I'm wondering when tire gauges became widely used for bicycles,
> which is an awfully vague question.
> After all, Frank Krygowski has pointed out that tire gauges may not
> be all that widely used even today.
> So I'm just looking for early references to bicyclists using tire
> gauges, recommended bicycle air pressures, pros using tire gauges,
> or bike catalogues trying to sell tire gauges.
> I got absolutely nowhere trying to find ancient Presta valve tire
> gauges. Everything around 1900 seems to be Schrader. Indeed, most
> of the antique gauges were made by Schrader.
> Ebay turned out to have lots of old tire gauges with pictures. The
> dates are iffy, since they often mention two or three patents from
> 1893 to 1923.
> The old gauges seem to come in two ranges, 10-50 psi for balloon
> tires versus 20-120 psi for more modern-style tires. As far as I
> can tell, both kinds of tires meant car tires.
I believe the reason for that, is that inflation pressure in bicycle
tires is adequately measured by thumb pressure while car tires defy
using that method. As cars came along, so did the pressure gauge.
People who didn't experience tubular tire days cannot recall how easy
sensing tire pressure is on a thin walled silk tire. In contrast, my
mother's heavy tubulars had Schrader valves and were inflated at the
bicycle shop after patching using an automobile hose end with gauge.
Because these tires were heavy "slugs" vulcanized in rubber all
around, they didn't respond well to thumb pressure and were patched by
inserting latex square cross section (office style) rubber bands in
the hole together with rubber cement and then trimmed flush with a
razor blade.
Jobst Brandt
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Date: 13 Oct 2007 19:32:30
From: Tom Sherman
Subject: Re: Oldest use of tire gauges on bicycles?
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jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> ...
> People who didn't experience tubular tire days cannot recall how easy
> sensing tire pressure is on a thin walled silk tire. In contrast, my
> mother's heavy tubulars had Schrader valves and were inflated at the
> bicycle shop after patching using an automobile hose end with gauge.
> Because these tires were heavy "slugs" vulcanized in rubber all
> around, they didn't respond well to thumb pressure and were patched by
> inserting latex square cross section (office style) rubber bands in
> the hole together with rubber cement and then trimmed flush with a
> razor blade.
The thumb test does not work well on heavy cased Maxxis Hookworms, or on
Mitsuboshi Tioga Comp Pools that have the extra rubber ridge on the side
(for riding up the walls of empty swimming pools [1] - hence the name).
[1] Despite their BMX freestyle origins, an excellent road tire for
small wheel bicycles and trikes.
--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!
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Date: 10 Oct 2007 23:56:05
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On 11 Oct 2007 03:47:04 GMT, jobst.brandt@stanfordalumni.org wrote:
>Carl Fogel writes:
>
>> I'm wondering when tire gauges became widely used for bicycles,
>> which is an awfully vague question.
>
>> After all, Frank Krygowski has pointed out that tire gauges may not
>> be all that widely used even today.
>
>> So I'm just looking for early references to bicyclists using tire
>> gauges, recommended bicycle air pressures, pros using tire gauges,
>> or bike catalogues trying to sell tire gauges.
>
>> I got absolutely nowhere trying to find ancient Presta valve tire
>> gauges. Everything around 1900 seems to be Schrader. Indeed, most
>> of the antique gauges were made by Schrader.
>
>> Ebay turned out to have lots of old tire gauges with pictures. The
>> dates are iffy, since they often mention two or three patents from
>> 1893 to 1923.
>
>> The old gauges seem to come in two ranges, 10-50 psi for balloon
>> tires versus 20-120 psi for more modern-style tires. As far as I
>> can tell, both kinds of tires meant car tires.
>
>I believe the reason for that, is that inflation pressure in bicycle
>tires is adequately measured by thumb pressure while car tires defy
>using that method. As cars came along, so did the pressure gauge.
>
>People who didn't experience tubular tire days cannot recall how easy
>sensing tire pressure is on a thin walled silk tire. In contrast, my
>mother's heavy tubulars had Schrader valves and were inflated at the
>bicycle shop after patching using an automobile hose end with gauge.
>Because these tires were heavy "slugs" vulcanized in rubber all
>around, they didn't respond well to thumb pressure and were patched by
>inserting latex square cross section (office style) rubber bands in
>the hole together with rubber cement and then trimmed flush with a
>razor blade.
>
>Jobst Brandt
Dear Jobst,
Morley Brothers has the rubber bands and the tool to stuff them into
the most stubborn tire:
http://www.fixedgeargallery.com/morley/11.jpg
More elaborate rubber-band inserters:
http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+24%2Ejpg
Here's the earliest tire gauge that I can find so far in a catalogue.
Note that it has the modern ability to stay at whatever pressure is
reached when removed and that it implies that earlier gauges had to
have the wheel turned so that the valve was at the bottom (?):
"Twitchell Air Gauge"
"This gauge is also known as the pencil gauge, as it is very small in
size. The Twitchell gauge can be used, no matter what the position of
the tire valve--no turning the wheel until the valve is at the bottom.
It has the new positive lock stop, and stays up so you can read the
pressure after the gauge has been taken off the valve. Shipping weight
4 ounces. $1.00 [?]"
http://www.nostalgic.net/pictures/1230.htm
Lower right corner, Twitchell Air Gauge, 1917 Hawthorne/Montgomery
Ward catalogue. It's actually in the motorcycle section, not the bike
section.
Some Twitchell pictures:
http://www.tias.com/cgi-bin/showcase-item.cgi?itemKey=1923015603&store=/stores/gea
Cheers,
Carl Fogel
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Date: 11 Oct 2007 10:48:30
From: A Muzi
Subject: Re: Oldest use of tire gauges on bicycles?
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>> Carl Fogel writes:
>>> I'm wondering when tire gauges became widely used for bicycles,
>>> which is an awfully vague question.
>>> After all, Frank Krygowski has pointed out that tire gauges may not
>>> be all that widely used even today.
>>> So I'm just looking for early references to bicyclists using tire
>>> gauges, recommended bicycle air pressures, pros using tire gauges,
>>> or bike catalogues trying to sell tire gauges.
>>> I got absolutely nowhere trying to find ancient Presta valve tire
>>> gauges. Everything around 1900 seems to be Schrader. Indeed, most
>>> of the antique gauges were made by Schrader.
>>> Ebay turned out to have lots of old tire gauges with pictures. The
>>> dates are iffy, since they often mention two or three patents from
>>> 1893 to 1923.
>>> The old gauges seem to come in two ranges, 10-50 psi for balloon
>>> tires versus 20-120 psi for more modern-style tires. As far as I
>>> can tell, both kinds of tires meant car tires.
> jobst.brandt@stanfordalumni.org wrote:
>> I believe the reason for that, is that inflation pressure in bicycle
>> tires is adequately measured by thumb pressure while car tires defy
>> using that method. As cars came along, so did the pressure gauge.
>> People who didn't experience tubular tire days cannot recall how easy
>> sensing tire pressure is on a thin walled silk tire. In contrast, my
>> mother's heavy tubulars had Schrader valves and were inflated at the
>> bicycle shop after patching using an automobile hose end with gauge.
>> Because these tires were heavy "slugs" vulcanized in rubber all
>> around, they didn't respond well to thumb pressure and were patched by
>> inserting latex square cross section (office style) rubber bands in
>> the hole together with rubber cement and then trimmed flush with a
>> razor blade.
carlfogel@comcast.net wrote:
> Morley Brothers has the rubber bands and the tool to stuff them into
> the most stubborn tire:
> http://www.fixedgeargallery.com/morley/11.jpg
> More elaborate rubber-band inserters:
> http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+24%2Ejpg
> Here's the earliest tire gauge that I can find so far in a catalogue.
> Note that it has the modern ability to stay at whatever pressure is
> reached when removed and that it implies that earlier gauges had to
> have the wheel turned so that the valve was at the bottom (?):
> "Twitchell Air Gauge"
> "This gauge is also known as the pencil gauge, as it is very small in
> size. The Twitchell gauge can be used, no matter what the position of
> the tire valve--no turning the wheel until the valve is at the bottom.
> It has the new positive lock stop, and stays up so you can read the
> pressure after the gauge has been taken off the valve. Shipping weight
> 4 ounces. $1.00 [?]"
> http://www.nostalgic.net/pictures/1230.htm
> Lower right corner, Twitchell Air Gauge, 1917 Hawthorne/Montgomery
> Ward catalogue. It's actually in the motorcycle section, not the bike
> section.
> Some Twitchell pictures:
> http://www.tias.com/cgi-bin/showcase-item.cgi?itemKey=1923015603&store=/stores/gea
Tire plugs, reamers and the slotted installer are unchanged and readily
available everywhere in USA. 'Tech' is the dominant supplier. There's a
set in my 'road trip' tool box.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 10 Oct 2007 23:50:49
From: A Muzi
Subject: Re: Oldest use of tire gauges on bicycles?
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> Carl Fogel writes:
>> I'm wondering when tire gauges became widely used for bicycles,
>> which is an awfully vague question.
>> After all, Frank Krygowski has pointed out that tire gauges may not
>> be all that widely used even today.
>> So I'm just looking for early references to bicyclists using tire
>> gauges, recommended bicycle air pressures, pros using tire gauges,
>> or bike catalogues trying to sell tire gauges.
>> I got absolutely nowhere trying to find ancient Presta valve tire
>> gauges. Everything around 1900 seems to be Schrader. Indeed, most
>> of the antique gauges were made by Schrader.
>> Ebay turned out to have lots of old tire gauges with pictures. The
>> dates are iffy, since they often mention two or three patents from
>> 1893 to 1923.
jobst.brandt@stanfordalumni.org wrote:
>> The old gauges seem to come in two ranges, 10-50 psi for balloon
>> tires versus 20-120 psi for more modern-style tires. As far as I
>> can tell, both kinds of tires meant car tires.
> I believe the reason for that, is that inflation pressure in bicycle
> tires is adequately measured by thumb pressure while car tires defy
> using that method. As cars came along, so did the pressure gauge.
> People who didn't experience tubular tire days cannot recall how easy
> sensing tire pressure is on a thin walled silk tire. In contrast, my
> mother's heavy tubulars had Schrader valves and were inflated at the
> bicycle shop after patching using an automobile hose end with gauge.
> Because these tires were heavy "slugs" vulcanized in rubber all
> around, they didn't respond well to thumb pressure and were patched by
> inserting latex square cross section (office style) rubber bands in
> the hole together with rubber cement and then trimmed flush with a
> razor blade.
That same technique's still used for auto tires, as nicely described in
the NY Times 'Metropolitan Diary' last Monday
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 10 Oct 2007 20:12:41
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Oct 10, 4:41 pm, carlfo...@comcast.net wrote:
>
> In any case, I'm having fun wondering how to test the claims about
> bouncing and thumbing and enjoying the reactions.
Our club used to sponsor a "family oriented" invitational ride,
featuring multiple choices of shorter rides in an extensive wooded
park, plus picnics, games, a concours d'elegance, etc.
One year we had a tire pumping contest. The object was to pump a tire
to 100 psi, judging the pressure without a gage.
As I recall, most of the (roughly) dozen entrants were quite close,
i.e. within about 5 psi, and the winner was dead on.
To be honest, we didn't take the trouble to actually calibrate the
gage we used, although I have the technology. So some poor soul may
have been cheated out of his thumb's just rewards.
- Frank Krygowski
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Date: 11 Oct 2007 13:22:37
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Wed, 10 Oct 2007 20:12:41 -0700, frkrygow@gmail.com wrote:
>On Oct 10, 4:41 pm, carlfo...@comcast.net wrote:
>>
>> In any case, I'm having fun wondering how to test the claims about
>> bouncing and thumbing and enjoying the reactions.
>
>Our club used to sponsor a "family oriented" invitational ride,
>featuring multiple choices of shorter rides in an extensive wooded
>park, plus picnics, games, a concours d'elegance, etc.
>
>One year we had a tire pumping contest. The object was to pump a tire
>to 100 psi, judging the pressure without a gage.
>
>As I recall, most of the (roughly) dozen entrants were quite close,
>i.e. within about 5 psi, and the winner was dead on.
>
>To be honest, we didn't take the trouble to actually calibrate the
>gage we used, although I have the technology. So some poor soul may
>have been cheated out of his thumb's just rewards.
>
>- Frank Krygowski
Dear Frank,
I like it . . .
But the James Randi magician on my shoulder bets me that he can
probably _pump_ his tire with _his_ pump to within 5 psi of 100 psi
blindfolded, without touching the tire with his thumb or bouncing it.
When I ask him how, he pretends to pump a handle and starts counting,
"One, two, three, four . . ."
I like that, too.
So I still wonder how well people would do checking my kind of slow
leaks, day after day, with a quick, casual thumb rather than feeling
the pump resistance and the tire changing every few seconds.
Cheers,
Carl Fogel
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Date: 11 Oct 2007 13:06:57
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<carlfogel@comcast.net > wrote in message
news:0dtsg3523u87tv0rekfbitqnjn0gkd5n5f@4ax.com...
>
> So I still wonder how well people would do checking my kind of slow
> leaks, day after day, with a quick, casual thumb rather than feeling
> the pump resistance and the tire changing every few seconds.
> Cheers,
> Carl Fogel
The same, with my thumb gauge.
Every few seconds???
Well I'll have to say Carl, you're the only cyclist I know who has
continuous problems with slow leaks.
I would hire a few domestiques to ride along side your 15.123 mi.journey.
-tom
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Date: 11 Oct 2007 15:20:18
From: A Muzi
Subject: Re: Oldest use of tire gauges on bicycles?
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> <carlfogel@comcast.net> wrote
>> So I still wonder how well people would do checking my kind of slow
>> leaks, day after day, with a quick, casual thumb rather than feeling
>> the pump resistance and the tire changing every few seconds.
Tom Nakashima wrote:
> The same, with my thumb gauge.
> Every few seconds???
> Well I'll have to say Carl, you're the only cyclist I know who has
> continuous problems with slow leaks.
> I would hire a few domestiques to ride along side your 15.123 mi.journey.
I hear you, man. Perhaps Pueblo has other charms besides goatheads?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 11 Oct 2007 14:48:03
From: A Muzi
Subject: Re: Oldest use of tire gauges on bicycles?
|
>> carlfo...@comcast.net wrote:
>>> In any case, I'm having fun wondering how to test the claims about
>>> bouncing and thumbing and enjoying the reactions.
> frkrygow@gmail.com wrote:
>> Our club used to sponsor a "family oriented" invitational ride,
>> featuring multiple choices of shorter rides in an extensive wooded
>> park, plus picnics, games, a concours d'elegance, etc.
>>
>> One year we had a tire pumping contest. The object was to pump a tire
>> to 100 psi, judging the pressure without a gage.
>>
>> As I recall, most of the (roughly) dozen entrants were quite close,
>> i.e. within about 5 psi, and the winner was dead on.
>>
>> To be honest, we didn't take the trouble to actually calibrate the
>> gage we used, although I have the technology. So some poor soul may
>> have been cheated out of his thumb's just rewards.
carlfogel@comcast.net wrote:
> But the James Randi magician on my shoulder bets me that he can
> probably _pump_ his tire with _his_ pump to within 5 psi of 100 psi
> blindfolded, without touching the tire with his thumb or bouncing it.
>
> When I ask him how, he pretends to pump a handle and starts counting,
> "One, two, three, four . . ."
>
> I like that, too.
>
> So I still wonder how well people would do checking my kind of slow
> leaks, day after day, with a quick, casual thumb rather than feeling
> the pump resistance and the tire changing every few seconds.
I'm not claiming supernatural accuracy. I air at work and then a couple
weeks later, when a tub feels soft, or if I look down and see the tire
squish out too much, I air it again. Probably 85 to 105 -ish psi sorta.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 09 Oct 2007 11:47:05
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Oct 9, 2:42 pm, Zog The Undeniable <hrothga...@yahoo.com > wrote:
> carlfo...@comcast.net wrote:
> > I'm wondering when tire gauges became widely used for bicycles, which
> > is an awfully vague question.
>
> What's wrong with "hard, or until you're fed up of pumping" for a road bike?
Well, I found to my dismay that pumping Continental Top Touring tires
"hard" caused eventual failure, i.e. bubbles in the sidewalls. :-(
For those tires, on a coast-to-coast trip, I ended up buying and using
a gage.
But for others, I've just judged by feel and done fine.
- Frank Krygowski
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Date: 09 Oct 2007 19:42:40
From: Zog The Undeniable
Subject: Re: Oldest use of tire gauges on bicycles?
|
carlfogel@comcast.net wrote:
> I'm wondering when tire gauges became widely used for bicycles, which
> is an awfully vague question.
What's wrong with "hard, or until you're fed up of pumping" for a road bike?
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Date: 09 Oct 2007 13:50:27
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Tue, 09 Oct 2007 19:42:40 +0100, Zog The Undeniable
<hrothgar19@yahoo.com > wrote:
>carlfogel@comcast.net wrote:
>> I'm wondering when tire gauges became widely used for bicycles, which
>> is an awfully vague question.
>
>What's wrong with "hard, or until you're fed up of pumping" for a road bike?
Dear Zog,
Oh, please! Even back in 1919 people knew better:
"Every automobile, motorcycle, or bicycle tire needs frequent testing
with an air pressure gauge. Owners lose money by not keeping their
tires inflated at the proper riding pressure. (Average pressure for
bicycle tires is 40 pounds.) Tire manufacturers will positively not
replace tires which have been over or underinflated."
http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+36%2Ejpg
Andrew Muzi reportedly has a man on his staff who does nothing but
purse his lips, shake his head, and say, "Sorry, sir, but Yellow
Jersey positively cannot honor your tire's warranty, since it was
clearly over--or perhaps under--inflated. You would have been wiser to
spend the $1.50 to purchase the necessary instrument for your tire's
proper inflation and salvation."
(Mike Jacoubowsky is said to have offered this specialist lavish sums
to quit Andrew's employ and ply his lucrative trade in California, but
Andrew retains his services by letting him keep the valve caps from
the customers' tires, an untaxed windfall that rivals the oil
depletion allowance.)
Your only possible excuse is that you own one of those modern degraded
bi-cycles equipped with the mysterious foreign "Presta" air valves, to
which no known pressure gauge can be fitted, so you are making a
dubious virtue of a painful necessity.
Should I discover a pre-1920 Presta valve tire gauge, I shall
immediately inform you, but I've looked through quite a few
catalogues so far without finding one.
Cheers,
Carl Fogel
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Date: 09 Oct 2007 13:17:33
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<carlfogel@comcast.net > wrote in message
news:hilng3l4kkr7mt2rkmn8j3sqgqp27bvhok@4ax.com...
> On Tue, 09 Oct 2007 19:42:40 +0100, Zog The Undeniable
>
> Your only possible excuse is that you own one of those modern degraded
> bi-cycles equipped with the mysterious foreign "Presta" air valves, to
> which no known pressure gauge can be fitted, so you are making a
> dubious virtue of a painful necessity.
>
> Should I discover a pre-1920 Presta valve tire gauge, I shall
> immediately inform you, but I've looked through quite a few
> catalogues so far without finding one.
> Cheers,
> Carl Fogel
What's wrong with using the tried & true, thumb gauge?
-tom
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Date: 09 Oct 2007 20:33:56
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Tue, 9 Oct 2007 13:17:33 -0700, "Tom Nakashima"
<tom@slac.stanford.edu > wrote:
>
><carlfogel@comcast.net> wrote in message
>news:hilng3l4kkr7mt2rkmn8j3sqgqp27bvhok@4ax.com...
>> On Tue, 09 Oct 2007 19:42:40 +0100, Zog The Undeniable
>>
>> Your only possible excuse is that you own one of those modern degraded
>> bi-cycles equipped with the mysterious foreign "Presta" air valves, to
>> which no known pressure gauge can be fitted, so you are making a
>> dubious virtue of a painful necessity.
>>
>> Should I discover a pre-1920 Presta valve tire gauge, I shall
>> immediately inform you, but I've looked through quite a few
>> catalogues so far without finding one.
>> Cheers,
>> Carl Fogel
>
>What's wrong with using the tried & true, thumb gauge?
>-tom
Dear Tom,
Thanks to Bishop Ussher, we know that your preferred instrument has
been in use for 6,011 years.
Inquiring minds may want to know how long more advanced methods have
been used by, say, Tour de France riders.
Even more inquiring minds sometimes long for a true blind test of the
venerable tire-pressure testing methods (thumbs, bouncing, seat of the
pants, and so forth).
I may be more interested than some posters because my Slime tubes and
goatheads give me more room for slow-leak tests.
My version of the thumb-test is to look at my mileage after my daily
ride. When it creeps up to 15.120 miles or 15.123 from a normal 15.095
to 15.105 on my trusty $10 Schwinn cyclocomputer, I know that my front
tire is losing air, probably from tiny pinholes semi-sealed by Slime,
enough to add about a dozen extra wheel revolutions to my daily ride.
(Talk about cheap, ridiculous accuracy!)
With no cyclocomputer attached to it, my rear tire is sneakier and
harder to guesstimate. I usually just slap the pump heead onto it,
pump it up until the Presta valve breaks free, and glumly note that
the needle is getting closer to 90 psi than the 110 psi that I put in
last weekend.
Thumb tests and bouncing probably work well enough for practical
bicycling purposes. But for those who enjoy blind-testing tales . . .
"Another example of a listening test (again, single-blind) was
arranged and broadcast in the mid-1970s by the BBC (see
http://www.abcviolins.com/fidfad.html [the live recording of the
braodcast] ). In this case the quality of the judging panel was high -
Charles Beare, Isaac Stern and Pinchas Zukerman. The instruments
played were a Stradivari, a Guarneri del Gèsu, a Vuillaume and a
Ronald Praill that was barely a year old. Two excerpts were played by
Manoug Parikian: the start of the Bruch G minor Concerto and a segment
of the Bach Chaconne."
"Before giving their answers, the judging panel spent some time
pointing out many of the deficiencies in the testing procedure. [Odd
how often experts do that!] The two excerpts played were too short and
limited in tonal possibilities, there was no chance to revisit each
instrument for extended comparisons, the studio represented only one
of many possible listening environments, and so on; all very valid
comments as the test was undoubtedly far too limited. However, the
good-natured panel proceeded to give out their judgements, many of
which proved to be incorrect [A polite way to say no better than
random guessing!] - the Praill was mistaken for both the Strad and the
Guarneri (Beare and Stern did the best with two out of four correct)."
http://www.abcviolins.com/blindlistening.html
Stuff like that makes me wonder what results a real blind test of
thumbs and bounce would produce.
Hmmm . . . I have a bike, an air pump with a gauge, and a concrete
floor to bounce it off. I wonder what the actual difference is between
a tire with 110 psi, 100, 90, and 80? Or how far a thumb-shaped pad
with a heavy weight will sink into a 700x25 tire at those pressures,
as measured by a dial gauge?
Cheers,
Carl Fogel
|
| | | | | |
Date: 10 Oct 2007 06:44:52
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<carlfogel@comcast.net > wrote in message
news:mscog3lt7rpk4tcq3uq36p87ckbf9narj7@4ax.com...
> On Tue, 9 Oct 2007 13:17:33 -0700, "Tom Nakashima"
> <tom@slac.stanford.edu> wrote:
>>
>>What's wrong with using the tried & true, thumb gauge?
>>-tom
>
> Dear Tom,
>
> My version of the thumb-test is to look at my mileage after my daily
> ride. When it creeps up to 15.120 miles or 15.123 from a normal 15.095
> to 15.105 on my trusty $10 Schwinn cyclocomputer, I know that my front
> tire is losing air, probably from tiny pinholes semi-sealed by Slime,
> enough to add about a dozen extra wheel revolutions to my daily ride.
>
> (Talk about cheap, ridiculous accuracy!)
>
>
> Hmmm . . . I have a bike, an air pump with a gauge, and a concrete
> floor to bounce it off. I wonder what the actual difference is between
> a tire with 110 psi, 100, 90, and 80? Or how far a thumb-shaped pad
> with a heavy weight will sink into a 700x25 tire at those pressures,
> as measured by a dial gauge?
>
> Cheers,
>
> Carl Fogel
Oh please Carl,
You ride with Slime in your tires, in a 53/11 on the flats for your daily
under 16 miles. And you have pumped up your tires.....how many times in your
lifespan???
By now you would think one would get a thumb gauge feel of psi between
90-100 lbs. Or as JB says; bounce the tire on the ground.
So let me guess, when you get a flat on the road, after you make the
repair, you whip out your trusty tire gauge and measure the pressure,
because you're worried that your mileage may vary between .05 and .2 miles?
Where is my plastic goblet for a shot of morning bourbon.
If we ever ride together someday Carl, I'm not waiting no more than
an hour at the summit.
-tom
|
| | | | | | |
Date: 10 Oct 2007 14:41:05
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Wed, 10 Oct 2007 06:44:52 -0700, "Tom Nakashima"
<tom@slac.stanford.edu > wrote:
>
><carlfogel@comcast.net> wrote in message
>news:mscog3lt7rpk4tcq3uq36p87ckbf9narj7@4ax.com...
>> On Tue, 9 Oct 2007 13:17:33 -0700, "Tom Nakashima"
>> <tom@slac.stanford.edu> wrote:
>>>
>>>What's wrong with using the tried & true, thumb gauge?
>>>-tom
>>
>> Dear Tom,
>>
>> My version of the thumb-test is to look at my mileage after my daily
>> ride. When it creeps up to 15.120 miles or 15.123 from a normal 15.095
>> to 15.105 on my trusty $10 Schwinn cyclocomputer, I know that my front
>> tire is losing air, probably from tiny pinholes semi-sealed by Slime,
>> enough to add about a dozen extra wheel revolutions to my daily ride.
>>
>> (Talk about cheap, ridiculous accuracy!)
>>
>>
>> Hmmm . . . I have a bike, an air pump with a gauge, and a concrete
>> floor to bounce it off. I wonder what the actual difference is between
>> a tire with 110 psi, 100, 90, and 80? Or how far a thumb-shaped pad
>> with a heavy weight will sink into a 700x25 tire at those pressures,
>> as measured by a dial gauge?
>>
>> Cheers,
>>
>> Carl Fogel
>
>Oh please Carl,
>You ride with Slime in your tires, in a 53/11 on the flats for your daily
>under 16 miles. And you have pumped up your tires.....how many times in your
>lifespan???
>By now you would think one would get a thumb gauge feel of psi between
>90-100 lbs. Or as JB says; bounce the tire on the ground.
> So let me guess, when you get a flat on the road, after you make the
>repair, you whip out your trusty tire gauge and measure the pressure,
>because you're worried that your mileage may vary between .05 and .2 miles?
>Where is my plastic goblet for a shot of morning bourbon.
>If we ever ride together someday Carl, I'm not waiting no more than
>an hour at the summit.
>-tom
Dear Tom,
Sorry, but I haven't developed the ability to detect the pressure
dropping 10 psi from slow leaks with my thumb or by bouncing.
Think about it. If you press your thumb on the same tire every day for
a week and it loses only a pound or two of pressure every day, are you
going to notice each tiny drop, or just get used to the gradual
change?
I suspect that a lot of seat-of-the-pants folks owe their success more
to having reliable tires that stay at the same pressure than to any
ability to detect slow leaks of the kind that I deal with all the
time.
In other words, I probably face the problem more often than you do.
So far, I've had 38 flats in 248 rides this year (I missed about 30
rides with unusually bad weather in January and February).
About half of them were slow leaks. My absurdly accurate mileage gives
me a hint about the front tire, but not about the rear.
So I pop the pump head onto the tires about once a week, pump them up
until the Presta valve pops open, look at the dial gauge, and get
suspicious when Slime tubes have lost 10 psi (or more) in a week.
It's more fun to pull the tube, see the slow leak, and replace it at
home, than to notice out on my ride.
In any case, I'm having fun wondering how to test the claims about
bouncing and thumbing and enjoying the reactions.
Cheers,
Carl Fogel
|
| | | | | | | |
Date: 11 Oct 2007 06:46:36
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<carlfogel@comcast.net > wrote in message
news:hddqg31uq039gd6h8pkeke03taifsq8q8l@4ax.com...
> On Wed, 10 Oct 2007 06:44:52 -0700, "Tom Nakashima"
>
> In any case, I'm having fun wondering how to test the claims about
> bouncing and thumbing and enjoying the reactions.
> Cheers,
> Carl Fogel
Carl,
Believe it or not, I can tell pressure of my tires from just the feel of the
ride. I've been riding the Mavic MA2 rims with the Avocet 28's, now the
25's with the same bike for many years. I've pumped up my tires at the same
tire pressure,100psi and got used to the feel, where I can detect pressure
change. I also have two older Silca floor pump with the pop-off pressure
valves. I haven't look at a tire pressure gauge for quite awhile.
What's funny, the two Silca floor pumps are off by a few psi between the
two. I can actually feel the difference on the ride.
When I flatten, I use a full size frame pump (not those mini things) for the
repair, and my thumb to gauge when the pressure is right. Most of the time I
can tell I'm slightly under pressure, but enough to get me home. Takes me
about 3- minutes to repair a flat and be back on the road pedaling, and
that's at a comfortable pace.
At the Great Western Bike Rally tire challenge, I was timed well under a
minute, but not even close to the winner.
-tom
|
| | | | | | | | |
Date: 11 Oct 2007 14:19:28
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Thu, 11 Oct 2007 06:46:36 -0700, "Tom Nakashima"
<tom@slac.stanford.edu > wrote:
>
><carlfogel@comcast.net> wrote in message
>news:hddqg31uq039gd6h8pkeke03taifsq8q8l@4ax.com...
>> On Wed, 10 Oct 2007 06:44:52 -0700, "Tom Nakashima"
>>
>> In any case, I'm having fun wondering how to test the claims about
>> bouncing and thumbing and enjoying the reactions.
>> Cheers,
>> Carl Fogel
>
>Carl,
>Believe it or not, I can tell pressure of my tires from just the feel of the
>ride. I've been riding the Mavic MA2 rims with the Avocet 28's, now the
>25's with the same bike for many years. I've pumped up my tires at the same
>tire pressure,100psi and got used to the feel, where I can detect pressure
>change. I also have two older Silca floor pump with the pop-off pressure
>valves. I haven't look at a tire pressure gauge for quite awhile.
>What's funny, the two Silca floor pumps are off by a few psi between the
>two. I can actually feel the difference on the ride.
>
>When I flatten, I use a full size frame pump (not those mini things) for the
>repair, and my thumb to gauge when the pressure is right. Most of the time I
>can tell I'm slightly under pressure, but enough to get me home. Takes me
>about 3- minutes to repair a flat and be back on the road pedaling, and
>that's at a comfortable pace.
>At the Great Western Bike Rally tire challenge, I was timed well under a
>minute, but not even close to the winner.
>-tom
Dear Tom,
I believe you, but I'm not sure what I'm believing.
For example, you may be able to feel the objective difference when you
inflate the tires with the two different pop-off pumps.
Or you may just be feeling the difference because you know which pump
you used and can't help expecting to feel the difference.
Similarly, you may be able to tell the objective low pressure of the
frame pump with your thumb after you fix a flat on the road. (Why
leave it lower than 100 psi?)
Or you may just be feeling the low pressure because you know that you
never to pump the tire up very high with your frame pump because the
pump resistance is more trouble than it's worth.
As for the ride feel, the same sort of things apply.
Sometimes I wonder why no one ever mentions detecting _over_ inflated
tires with their thumbs. It's as if they unconsciously detect the
right pressure while they pump and then press their thumb to the tire
and declare victory.
A really good test would probably involve the same tire presented to
the thumb (or bounced) once a day for two weeks, with the pressure
randomly varied by a helper between say 90, 95, 100, 105, and 110 psi
(That is, 5 and 10 psi either way from whatever pressure the tester
wants it to be. You can't have the pressures too close, but you can't
have them too far apart. And you want a realistic time lapse of a day
and no idea of the pump action, so there's no question of comparing
different pressures or of knowing that the pressure _must_ be rising
because the tire was pumped another stroke or two.)
Have the helper set the pressure without the thumber in the room and
leave or at least stand behind the thumber, so there's no question
about the helper unconsciously giving away the setting.
(If you think that's silly, remember that clever Hans could do simple
arithmetic flawlessly, but only when spectators were visible to
unconsciously cue him by relaxing slightly when Hans reached the right
number of hoof taps--not bad for a horse.)
http://en.wikipedia.org/wiki/Clever_Hans
(Ignoring tire-testing, be sure to read down to the Lisa Simpson
section and the comment near the end about the psychologist being
bitten.)
A thumber and helper test would show whether _one_ person really can
tell the difference. If he can, it seems reasonable that others can,
too. If he can't, it doesn't mean that no one can.
It would be an interesting experiment and not much trouble, just a few
minutes a day for two weeks with a helper with a pump, a piece of
paper with the pre-selected random pressures, and another piece of
paper to record what the thumber or bouncer indicated.
At least four posters have indicated here and elsewhere that they
think that their thumbs are pretty good at checking pressure, so it
seems to me that it may be possible. I'm just curious what real
testing would show.
Back to looking for really old air gauges in bike catalogues. I still
can't find a hint of an early Presta valve, much less a Presta gauge,
but I'm looking in U.S. literature. That may indicate that Europeans
have always known how to tell pressure with a thumb, at least well
enough for racing.
Cheers,
Carl Fogel
|
| | | | | | | | | |
Date: 11 Oct 2007 22:58:03
From: M-gineering
Subject: Re: Oldest use of tire gauges on bicycles?
|
carlfogel@comcast.net wrote:
>
> Back to looking for really old air gauges in bike catalogues. I still
> can't find a hint of an early Presta valve, much less a Presta gauge,
> but I'm looking in U.S. literature. That may indicate that Europeans
> have always known how to tell pressure with a thumb, at least well
> enough for racing.
>
> Cheers,
>
> Carl Fogel
have a look at the 1900 edition of the guide Michelin. Don't know if it
is online, but it was reprinted. Precursors to presta valves are shown
(missing locknut), advice is given to frequently pump new tyres to
compensate for growth, etc. Cardrivers are advised to pack a 'pompe a
manometre', cyclist should just pump their tyres hard
--
/Marten
info(apestaartje)m-gineering(punt)nl
|
| | | | | | | | | | |
Date: 20 Oct 2007 00:32:16
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Thu, 11 Oct 2007 22:58:03 +0200, M-gineering
<ikmotgeenspam@m-gineering.nl > wrote:
>carlfogel@comcast.net wrote:
>
>>
>> Back to looking for really old air gauges in bike catalogues. I still
>> can't find a hint of an early Presta valve, much less a Presta gauge,
>> but I'm looking in U.S. literature. That may indicate that Europeans
>> have always known how to tell pressure with a thumb, at least well
>> enough for racing.
>>
>> Cheers,
>>
>> Carl Fogel
>
>have a look at the 1900 edition of the guide Michelin. Don't know if it
>is online, but it was reprinted. Precursors to presta valves are shown
>(missing locknut), advice is given to frequently pump new tyres to
>compensate for growth, etc. Cardrivers are advised to pack a 'pompe a
>manometre', cyclist should just pump their tyres hard
Dear Marten,
It is shameful to prey upon the helpless lust of a bibliophile, so I
started a new thread to expose your wickedness to a wider audience.
Thanks!
Cheers,
Carl Fogel
|
| | | | | | | | | | | |
Date: 20 Oct 2007 08:53:02
From: M-gineering
Subject: Re: Oldest use of tire gauges on bicycles?
|
carlfogel@comcast.net wrote:
> On Thu, 11 Oct 2007 22:58:03 +0200, M-gineering
> <ikmotgeenspam@m-gineering.nl> wrote:
>
>> carlfogel@comcast.net wrote:
>>
>>> Back to looking for really old air gauges in bike catalogues. I still
>>> can't find a hint of an early Presta valve, much less a Presta gauge,
>>> but I'm looking in U.S. literature. That may indicate that Europeans
>>> have always known how to tell pressure with a thumb, at least well
>>> enough for racing.
>>>
>>> Cheers,
>>>
>>> Carl Fogel
>> have a look at the 1900 edition of the guide Michelin. Don't know if it
>> is online, but it was reprinted. Precursors to presta valves are shown
>> (missing locknut), advice is given to frequently pump new tyres to
>> compensate for growth, etc. Cardrivers are advised to pack a 'pompe a
>> manometre', cyclist should just pump their tyres hard
>
> Dear Marten,
>
> It is shameful to prey upon the helpless lust of a bibliophile, so I
> started a new thread to expose your wickedness to a wider audience.
>
> Thanks!
>
> Cheers,
>
> Carl Fogel
Coming from a family where, the moment my mother turned her back, every
cm of spare wall was covered with books 3 rows deep, I'll have to plead
for mitigating circumstances ;)
--
/Marten
info(apestaartje)m-gineering(punt)nl
|
| | | | | | | | | |
Date: 11 Oct 2007 14:06:20
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<carlfogel@comcast.net > wrote in message
news:39usg353pudo5e88kvbsskgd7ecm6euqd3@4ax.com...
>
> At least four posters have indicated here and elsewhere that they
> think that their thumbs are pretty good at checking pressure, so it
> seems to me that it may be possible. I'm just curious what real
> testing would show.
> Cheers,
> Carl Fogel
Carl, Carl,
we're talking air in the tires...on a bicycle, psi not millibars.
How accurate do you want to be?
Geeze, I've been using the space bar quite a lot today, hope I can
check my tires when I get home.
-tom
|
| | | | | | | | | | |
Date: 11 Oct 2007 19:01:45
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Thu, 11 Oct 2007 14:06:20 -0700, "Tom Nakashima"
<tom@slac.stanford.edu > wrote:
>
><carlfogel@comcast.net> wrote in message
>news:39usg353pudo5e88kvbsskgd7ecm6euqd3@4ax.com...
>>
>> At least four posters have indicated here and elsewhere that they
>> think that their thumbs are pretty good at checking pressure, so it
>> seems to me that it may be possible. I'm just curious what real
>> testing would show.
>> Cheers,
>> Carl Fogel
>
>Carl, Carl,
>we're talking air in the tires...on a bicycle, psi not millibars.
>How accurate do you want to be?
>Geeze, I've been using the space bar quite a lot today, hope I can
>check my tires when I get home.
>-tom
Dear Tom,
Er, probably more accurate than somewhere between 90 and 110 psi?
As a sidelight, I've been wondering about tire bouncers. For some
reason, I suspect that they bounce only the front tire.
If not, they've developed the ability to distinguish how a rear tire
with 55% to 60% of the bike's weight bounces, as opposed to how a
front tire bounces with 45% to 40% of the weight.
How they'd judge rear tire bounces with and without their well-filled
touring bag behind the saddle is beyond me, but maybe it can be done.
Maybe different weights bounce just as high off the same inflation?
For those curious about the physics, here's a nice, short, clear
description of air pressure versus bouncing in one common object:
http://www.usc.edu/CSSF/History/2005/Projects/J0220.pdf
I may track down a dad with a video cam, but 700c tires bounce so
little when dropped from typical heights that differences due to air
pressure may not show up even at 30 frames per second. Maybe bouncers
judge more by the noise?
I expect that your tires (and the tires of other thumbers and
bouncers) work fine. I'm just curious whether the accuracy is as good
as usually implied.
Cheers,
Carl Fogel
|
| | | | | | | | | | | |
Date: 12 Oct 2007 01:54:55
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
Carl Fogel writes:
>>> At least four posters have indicated here and elsewhere that they
>>> think that their thumbs are pretty good at checking pressure, so it
>>> seems to me that it may be possible. I'm just curious what real
>>> testing would show.
>>> Cheers,
>> Carl, Carl, we're talking air in the tires...on a bicycle, psi not
>> millibars. How accurate do you want to be? Geeze, I've been using
>> the space bar quite a lot today, hope I can check my tires when I
>> get home.
> Dear Tom,
> Er, probably more accurate than somewhere between 90 and 110 psi?
> As a sidelight, I've been wondering about tire bouncers. For some
> reason, I suspect that they bounce only the front tire.
"they" come right out and say it, you think I am lying, a term that
seems to escape it's severity when you apply it. If you think I like
to ride on a soft rear tire, you are mistaken. I bounce first the
front and then the rear of my bicycle when I head out the door. The
rebound speed and sound of the wooden floor makes inflation level
apparent.
> If not, they've developed the ability to distinguish how a rear tire
> with 55% to 60% of the bike's weight bounces, as opposed to how a
> front tire bounces with 45% to 40% of the weight.
You're trying hard, but no cigar. Bouncing the front and rear of my
bicycle is not alike but I can tell the difference and know what it
means.
> How they'd judge rear tire bounces with and without their
> well-filled touring bag behind the saddle is beyond me, but maybe it
> can be done.
I think you can imagine the difference between the thud of a flat tire
with no rebound and the multiple rebounds of a hard tire, if you tried
it. This sounds like the folks who insisted that I can't measure
chain wear with a wooden "free sample" yardstick from the hardware
store.
> Maybe different weights bounce just as high off the same inflation?
...and MAYBE the moon is really made of green cheese.
Try it before you explain how it doesn't work.
> For those curious about the physics, here's a nice, short, clear
> description of air pressure versus bouncing in one common object:
http://www.usc.edu/CSSF/History/2005/Projects/J0220.pdf
> I may track down a dad with a video cam, but 700c tires bounce so
> little when dropped from typical heights that differences due to air
> pressure may not show up even at 30 frames per second. Maybe
> bouncers judge more by the noise?
Back off. All that web searching doesn't make any difference to those
who test tire pressure by thumb or by bounce. You're dodging the
bullets of doubt with apparent data searches.
> I expect that your tires (and the tires of other thumbers and
> bouncers) work fine. I'm just curious whether the accuracy is as
> good as usually implied.
Implied is that it's good enough for those who practice it.
Jobst Brandt
|
| | | | | | | | | | | | |
Date: 12 Oct 2007 06:47:27
From: Tom Nakashima
Subject: Re: Oldest use of tire gauges on bicycles?
|
<jobst.brandt@stanfordalumni.org > wrote in message
news:470ed3ef$0$14108$742ec2ed@news.sonic.net...
>> Carl Fogel writes:
>> I expect that your tires (and the tires of other thumbers and
>> bouncers) work fine. I'm just curious whether the accuracy is as
>> good as usually implied.
>
> Back off. All that web searching doesn't make any difference to those
> who test tire pressure by thumb or by bounce. You're dodging the
> bullets of doubt with apparent data searches.
> Implied is that it's good enough for those who practice it.
> Jobst Brandt
Carl,
I love reading some of your data searches, but sometimes it's overwhelming
or overkill for some of the simple things related to the bicycle.
I once met an accurate piano tuner who could tune a piano with just a tuning
fork, a bamboo fly-rod maker who could pick up a rod blank, swish it in the
air and tell if it would be a good casting rod. A master violin bow maker
who could do the same. A brick layer who used just string to make
alignments. A chef who uses a pinch to measure. A lot of these things are
through experience, just as bouncing a tire on the floor or using your thumb
to check air pressure in the tires. I do admire these people who could do
that, tells me they've been through the mill. I once asked JB how he was
able to measure brake rim wear while riding in the Alps. He told me he used
the straight-edge of a card.
You too can teach yourself these things if you allow yourself to.
-tom
|
| | | | | | | | | | | | | |
Date: 12 Oct 2007 14:29:01
From: _
Subject: Re: Oldest use of tire gauges on bicycles?
|
On Fri, 12 Oct 2007 06:47:27 -0700, Tom Nakashima wrote:
> I once asked JB how he was
> able to measure brake rim wear while riding in the Alps. He told me he used
> the straight-edge of a card.
That's an excellent idea. All you have to do is adjust your brakes so that
the pads hit the rim in the centre of the track, and measure against the
edges. Any careful cyclist can do that, and the gap will be easily visible
- and with practice you can guage the thickness. So simple, really...
|
| | | | | | | | | | | | | | |
Date: 12 Oct 2007 16:39:17
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
Jay Taylor writes:
>> I once asked JB how he was able to measure brake rim wear while
>> riding in the Alps. He told me he used the straight-edge of a
>> card.
> That's an excellent idea. All you have to do is adjust your brakes
> so that the pads hit the rim in the centre of the track, and measure
> against the edges. Any careful cyclist can do that, and the gap
> will be easily visible - and with practice you can gauge the
> thickness. So simple, really...
Oops, that doesn't work with the right side of a front rim with dual
pivot brakes because that brake arm has significant cosine error that
sweeps it up into the tire and therefore wears off the upper edge of
the rim. Be careful to use that method on the right side only, it
having a center pivoted brake arm.
Actually, using thumb and forefinger as a caliper, wiped across the
brake track gives a good feel of rim wear. I have been fortunate
these last few years to not descend in the rain on my summer tour and
have therefore ridden the same rims for many miles. I can thank Kool
Stop salmon red pads for not gratuitously developing embedded aluminum
oxide cutting tools from particles of road grit. I cringe when I hear
the grating sound of a rider descending with embedded metal in the
brake pads, visualizing the damage to the rim.
Jobst Brandt
|
| | | | | | | | | | | | | |
Date: 12 Oct 2007 06:59:11
From: jim beam
Subject: Re: Oldest use of tire gauges on bicycles?
|
Tom Nakashima wrote:
> <jobst.brandt@stanfordalumni.org> wrote in message
> news:470ed3ef$0$14108$742ec2ed@news.sonic.net...
>
>>> Carl Fogel writes:
>>> I expect that your tires (and the tires of other thumbers and
>>> bouncers) work fine. I'm just curious whether the accuracy is as
>>> good as usually implied.
>
>
>> Back off. All that web searching doesn't make any difference to those
>> who test tire pressure by thumb or by bounce. You're dodging the
>> bullets of doubt with apparent data searches.
>> Implied is that it's good enough for those who practice it.
>> Jobst Brandt
>
> Carl,
> I love reading some of your data searches, but sometimes it's overwhelming
> or overkill for some of the simple things related to the bicycle.
> I once met an accurate piano tuner who could tune a piano with just a tuning
> fork, a bamboo fly-rod maker who could pick up a rod blank, swish it in the
> air and tell if it would be a good casting rod. A master violin bow maker
> who could do the same. A brick layer who used just string to make
> alignments. A chef who uses a pinch to measure. A lot of these things are
> through experience, just as bouncing a tire on the floor or using your thumb
> to check air pressure in the tires. I do admire these people who could do
> that, tells me they've been through the mill. I once asked JB how he was
> able to measure brake rim wear while riding in the Alps. He told me he used
> the straight-edge of a card.
that's flawed methodology - it assumes that there are portions that
don't wear and that the worn part can be assessed against them. if the
"reference" is itself worn, there is no comparison possible.
> You too can teach yourself these things if you allow yourself to.
> -tom
>
>
|
| | | | | | | | | | | | |
Date: 12 Oct 2007 04:36:02
From: Ryan Cousineau
Subject: Re: Oldest use of tire gauges on bicycles?
|
In article <470ed3ef$0$14108$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> Carl Fogel writes:
>
> >>> At least four posters have indicated here and elsewhere that they
> >>> think that their thumbs are pretty good at checking pressure, so it
> >>> seems to me that it may be possible. I'm just curious what real
> >>> testing would show.
> >>> Cheers,
>
> >> Carl, Carl, we're talking air in the tires...on a bicycle, psi not
> >> millibars. How accurate do you want to be? Geeze, I've been using
> >> the space bar quite a lot today, hope I can check my tires when I
> >> get home.
>
> > Dear Tom,
>
> > Er, probably more accurate than somewhere between 90 and 110 psi?
>
> > As a sidelight, I've been wondering about tire bouncers. For some
> > reason, I suspect that they bounce only the front tire.
>
> "they" come right out and say it, you think I am lying, a term that
> seems to escape it's severity when you apply it. If you think I like
> to ride on a soft rear tire, you are mistaken. I bounce first the
> front and then the rear of my bicycle when I head out the door. The
> rebound speed and sound of the wooden floor makes inflation level
> apparent.
Jobst: there's a big difference between "lying" and "mistaken."
> > If not, they've developed the ability to distinguish how a rear tire
> > with 55% to 60% of the bike's weight bounces, as opposed to how a
> > front tire bounces with 45% to 40% of the weight.
>
> You're trying hard, but no cigar. Bouncing the front and rear of my
> bicycle is not alike but I can tell the difference and know what it
> means.
At the risk of verging from mediation to taunting, I need some numbers
here: how many PSI does the tire have to be down before it's detectable?
Could you pass Carl's proposed double-blind pressure-testing-test?
> > I expect that your tires (and the tires of other thumbers and
> > bouncers) work fine. I'm just curious whether the accuracy is as
> > good as usually implied.
>
> Implied is that it's good enough for those who practice it.
This may be the missing link. Tire pressures don't matter that much for
a lot of riding.
On my commuter, I really don't care what the tire pressures are. When
they dip below 60 psi, I usually notice and pump them back to about 90.
I use the gauge on my pump. These are, I don't know, 27x1-1/4 tires, I
think.
If I'm being diligent, I catch them at 65 psi.
Cyclocross and MTB disciplines, now there's where the blackest arts of
tire pressure choices come to the fore.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing
|
| | | | | | | | | | | | | |
Date: 12 Oct 2007 11:22:18
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
Ryan Cousineau <rcousine@sfu.ca > writes:
>>>>> At least four posters have indicated here and elsewhere that
>>>>> they think that their thumbs are pretty good at checking
>>>>> pressure, so it seems to me that it may be possible. I'm just
>>>>> curious what real testing would show.
>>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
>>>> not millibars. How accurate do you want to be? Geeze, I've been
>>>> using the space bar quite a lot today, hope I can check my tires
>>>> when I get home.
>>> Dear Tom,
>>> Er, probably more accurate than somewhere between 90 and 110 psi?
>>> As a sidelight, I've been wondering about tire bouncers. For some
>>> reason, I suspect that they bounce only the front tire.
>> "they" come right out and say it, you think I am lying, a term that
>> seems to escape it's severity when you apply it. If you think I
>> like to ride on a soft rear tire, you are mistaken. I bounce first
>> the front and then the rear of my bicycle when I head out the door.
>> The rebound speed and sound of the wooden floor makes inflation
>> level apparent.
> Jobst: there's a big difference between "lying" and "mistaken."
I don't know how much closer you can get to putting words in someone's
mouth than Carl's suspicions about tire bouncers. I clearly stated
that I check my tires by bouncing them (plural) and that considering
that they might have a slow leak or some other anomaly, they should
bounce as they did when freshly inflated.
For example, on my 2000mi tour of the Alps in the summer, taking about
three weeks, I don't pump the tires at all after leaving home in the
USA but test to see if everything is OK by bouncing the wheels before
taking off in the morning, just as I do at home. Saying that I
probably only bounce the front wheel is a stretch of the imagination.
>>> If not, they've developed the ability to distinguish how a rear
>>> tire with 55% to 60% of the bike's weight bounces, as opposed to
>>> how a front tire bounces with 45% to 40% of the weight.
>> You're trying hard, but no cigar. Bouncing the front and rear of
>> my bicycle is not alike but I can tell the difference and know what
>> it means.
> At the risk of verging from mediation to taunting, I need some
> numbers here: how many PSI does the tire have to be down before it's
> detectable? Could you pass Carl's proposed double-blind
> pressure-testing-test?
I usually inflate to 100psi with my floor pump and find less than
90psi detectably softer. I don't care if it is between 85 and 100.
That's good enough.
>>> I expect that your tires (and the tires of other thumbers and
>>> bouncers) work fine. I'm just curious whether the accuracy is as
>>> good as usually implied.
>> Implied is that it's good enough for those who practice it.
> This may be the missing link. Tire pressures don't matter that much
> for a lot of riding.
So why make such an analytical fuss about it and impute the motives of
those who don't test and keep records of exact inflation numbers?
> On my commuter, I really don't care what the tire pressures are.
> When they dip below 60 psi, I usually notice and pump them back to
> about 90. I use the gauge on my pump. These are, I don't know,
> 27x1-1/4 tires, I think.
> If I'm being diligent, I catch them at 65 psi.
> Cyclocross and MTB disciplines, now there's where the blackest arts
> of tire pressure choices come to the fore.
That depends on how soft the average terrain is. The softer, the
softer the tire and the more careful one must be with snake bites.
Jobst Brandt
|
| | | | | | | | | | | | | | |
Date: 13 Oct 2007 02:49:09
From: Ryan Cousineau
Subject: Re: Oldest use of tire gauges on bicycles?
|
In article <470f58ea$0$14122$742ec2ed@news.sonic.net >,
jobst.brandt@stanfordalumni.org wrote:
> Ryan Cousineau <rcousine@sfu.ca> writes:
>
> >>>>> At least four posters have indicated here and elsewhere that
> >>>>> they think that their thumbs are pretty good at checking
> >>>>> pressure, so it seems to me that it may be possible. I'm just
> >>>>> curious what real testing would show.
>
> >>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
> >>>> not millibars. How accurate do you want to be? Geeze, I've been
> >>>> using the space bar quite a lot today, hope I can check my tires
> >>>> when I get home.
>
> >>> Dear Tom,
>
> >>> Er, probably more accurate than somewhere between 90 and 110 psi?
>
> >>> As a sidelight, I've been wondering about tire bouncers. For some
> >>> reason, I suspect that they bounce only the front tire.
>
> >> "they" come right out and say it, you think I am lying, a term that
> >> seems to escape it's severity when you apply it. If you think I
> >> like to ride on a soft rear tire, you are mistaken. I bounce first
> >> the front and then the rear of my bicycle when I head out the door.
> >> The rebound speed and sound of the wooden floor makes inflation
> >> level apparent.
>
> > Jobst: there's a big difference between "lying" and "mistaken."
>
> I don't know how much closer you can get to putting words in someone's
> mouth than Carl's suspicions about tire bouncers. I clearly stated
> that I check my tires by bouncing them (plural) and that considering
> that they might have a slow leak or some other anomaly, they should
> bounce as they did when freshly inflated.
Carl isn't saying you don't do that. He's saying that test does not give
you as high a degree of accuracy as you think it does. He's accusing
you, at worst, of unconscious self-deception. That's not lying, that's
being mistaken.
> I usually inflate to 100psi with my floor pump and find less than
> 90psi detectably softer. I don't care if it is between 85 and 100.
> That's good enough.
>
> >>> I expect that your tires (and the tires of other thumbers and
> >>> bouncers) work fine. I'm just curious whether the accuracy is as
> >>> good as usually implied.
>
> >> Implied is that it's good enough for those who practice it.
This discussion started not with the question of whether the method was
good enough. It certainly seems to be! But whether it was as accurate as
some people thought (some claims were in the range of 5 psi, which to
your favour, is less accuracy than you have asserted in this post).
> > This may be the missing link. Tire pressures don't matter that much
> > for a lot of riding.
>
> So why make such an analytical fuss about it and impute the motives of
> those who don't test and keep records of exact inflation numbers?
Jobst, I'm being charitable! And so is Carl. He's not imputing your
motives, only your accuracy. And less than you yourself imputed!
> > Cyclocross and MTB disciplines, now there's where the blackest arts
> > of tire pressure choices come to the fore.
>
> That depends on how soft the average terrain is. The softer, the
> softer the tire and the more careful one must be with snake bites.
But of course. My typical dilemma is that a course will have a bunch of
soft terrain and a few hard obstacles. I want to set my pressure for the
soft terrain, but may end up leaning harder to avoid snakebites. Curb
hops are a dilemma-inducing obstacle on courses where they crop up.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing
|
| | | | | | | | | | | | | | | |
Date: 13 Oct 2007 19:24:18
From: Tom Sherman
Subject: Re: Oldest use of tire gauges on bicycles?
|
Ryan Cousineau wrote:
> In article <470f58ea$0$14122$742ec2ed@news.sonic.net>,
> jobst.brandt@stanfordalumni.org wrote:
>
>> Ryan Cousineau <rcousine@sfu.ca> writes:
>>
>>>>>>> At least four posters have indicated here and elsewhere that
>>>>>>> they think that their thumbs are pretty good at checking
>>>>>>> pressure, so it seems to me that it may be possible. I'm just
>>>>>>> curious what real testing would show.
>>>>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
>>>>>> not millibars. How accurate do you want to be? Geeze, I've been
>>>>>> using the space bar quite a lot today, hope I can check my tires
>>>>>> when I get home.
>>>>> Dear Tom,
>>>>> Er, probably more accurate than somewhere between 90 and 110 psi?
>>>>> As a sidelight, I've been wondering about tire bouncers. For some
>>>>> reason, I suspect that they bounce only the front tire.
>>>> "they" come right out and say it, you think I am lying, a term that
>>>> seems to escape it's severity when you apply it. If you think I
>>>> like to ride on a soft rear tire, you are mistaken. I bounce first
>>>> the front and then the rear of my bicycle when I head out the door.
>>>> The rebound speed and sound of the wooden floor makes inflation
>>>> level apparent.
>>> Jobst: there's a big difference between "lying" and "mistaken."
>> I don't know how much closer you can get to putting words in someone's
>> mouth than Carl's suspicions about tire bouncers. I clearly stated
>> that I check my tires by bouncing them (plural) and that considering
>> that they might have a slow leak or some other anomaly, they should
>> bounce as they did when freshly inflated.
>
> Carl isn't saying you don't do that. He's saying that test does not give
> you as high a degree of accuracy as you think it does. He's accusing
> you, at worst, of unconscious self-deception. That's not lying, that's
> being mistaken.
>
>> I usually inflate to 100psi with my floor pump and find less than
>> 90psi detectably softer. I don't care if it is between 85 and 100.
>> That's good enough.
>>
>>>>> I expect that your tires (and the tires of other thumbers and
>>>>> bouncers) work fine. I'm just curious whether the accuracy is as
>>>>> good as usually implied.
>>>> Implied is that it's good enough for those who practice it.
>
> This discussion started not with the question of whether the method was
> good enough. It certainly seems to be! But whether it was as accurate as
> some people thought (some claims were in the range of 5 psi, which to
> your favour, is less accuracy than you have asserted in this post).
>
>>> This may be the missing link. Tire pressures don't matter that much
>>> for a lot of riding.
>> So why make such an analytical fuss about it and impute the motives of
>> those who don't test and keep records of exact inflation numbers?
>
> Jobst, I'm being charitable! And so is Carl. He's not imputing your
> motives, only your accuracy. And less than you yourself imputed!
Yes, "Dear Carl" would NEVER do that [1]. [end sarcasm]
[1] Intentional indefinite pronoun - "that" refers to "Impute the
motives of another".
--
Tom Sherman - Holstein-Friesland Bovinia
Beer - It's not just for breakfast anymore!
|
| | | | | | | | | | | | | | | |
Date: 13 Oct 2007 03:06:25
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
Ryan Cousineau writes:
>>>>>>> At least four posters have indicated here and elsewhere that
>>>>>>> they think that their thumbs are pretty good at checking
>>>>>>> pressure, so it seems to me that it may be possible. I'm just
>>>>>>> curious what real testing would show.
>>>>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
>>>>>> not millibars. How accurate do you want to be? Geeze, I've been
>>>>>> using the space bar quite a lot today, hope I can check my tires
>>>>>> when I get home.
>>>>> Dear Tom,
>>>>> Er, probably more accurate than somewhere between 90 and 110 psi?
>>>>> As a sidelight, I've been wondering about tire bouncers. For some
>>>>> reason, I suspect that they bounce only the front tire.
>>>> "they" come right out and say it, you think I am lying, a term that
>>>> seems to escape it's severity when you apply it. If you think I
>>>> like to ride on a soft rear tire, you are mistaken. I bounce first
>>>> the front and then the rear of my bicycle when I head out the door.
>>>> The rebound speed and sound of the wooden floor makes inflation
>>>> level apparent.
He said "I suspect that they bounce only the front tire" in contrast
to what I said and then built up his thread on that.
>>> Jobst: there's a big difference between "lying" and "mistaken."
There was no mention of "mistaken".
>> I don't know how much closer you can get to putting words in
>> someone's mouth than Carl's suspicions about tire bouncers. I
>> clearly stated that I check my tires by bouncing them (plural) and
>> that considering that they might have a slow leak or some other
>> anomaly, they should bounce as they did when freshly inflated.
> Carl isn't saying you don't do that. He's saying that test does not
> give you as high a degree of accuracy as you think it does. He's
> accusing you, at worst, of unconscious self-deception. That's not
> lying, that's being mistaken.
He is too. Just read what he said. You fell for his style of
insinuations as thought they weren't what they are.
Jobst Brandt
|
| | | | | | | | | | | | | | | | |
Date: 12 Oct 2007 20:21:50
From: jim beam
Subject: Re: Oldest use of tire gauges on bicycles?
|
jobst.brandt@stanfordalumni.org wrote:
> Ryan Cousineau writes:
>
>>>>>>>> At least four posters have indicated here and elsewhere that
>>>>>>>> they think that their thumbs are pretty good at checking
>>>>>>>> pressure, so it seems to me that it may be possible. I'm just
>>>>>>>> curious what real testing would show.
>
>>>>>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
>>>>>>> not millibars. How accurate do you want to be? Geeze, I've been
>>>>>>> using the space bar quite a lot today, hope I can check my tires
>>>>>>> when I get home.
>
>>>>>> Dear Tom,
>
>>>>>> Er, probably more accurate than somewhere between 90 and 110 psi?
>
>>>>>> As a sidelight, I've been wondering about tire bouncers. For some
>>>>>> reason, I suspect that they bounce only the front tire.
>
>>>>> "they" come right out and say it, you think I am lying, a term that
>>>>> seems to escape it's severity when you apply it. If you think I
>>>>> like to ride on a soft rear tire, you are mistaken. I bounce first
>>>>> the front and then the rear of my bicycle when I head out the door.
>>>>> The rebound speed and sound of the wooden floor makes inflation
>>>>> level apparent.
>
> He said "I suspect that they bounce only the front tire" in contrast
> to what I said and then built up his thread on that.
>
>>>> Jobst: there's a big difference between "lying" and "mistaken."
>
> There was no mention of "mistaken".
>
>>> I don't know how much closer you can get to putting words in
>>> someone's mouth than Carl's suspicions about tire bouncers. I
>>> clearly stated that I check my tires by bouncing them (plural) and
>>> that considering that they might have a slow leak or some other
>>> anomaly, they should bounce as they did when freshly inflated.
>
>> Carl isn't saying you don't do that. He's saying that test does not
>> give you as high a degree of accuracy as you think it does. He's
>> accusing you, at worst, of unconscious self-deception. That's not
>> lying, that's being mistaken.
>
> He is too. Just read what he said. You fell for his style of
> insinuations as thought they weren't what they are.
>
you sound like the shade tree mechanic trying to say it's not necessary
to use a torque wrench. fact: even the most experienced mechanic can
rarely achieve within 30% accuracy on his "expert" and "practiced"
guesswork, and with huge results variance from instance to instance. a
good torque wrench otoh gets to within 1% accuracy every single time.
given that any decent floor pump has a pressure gauge in it, and that
they work, i really can't see why you have to make out like there's some
justification for not using one and dress it up like it's a defense
against a lie accusation.
|
| | | | | | | | | | | | | | |
Date: 12 Oct 2007 12:57:58
From:
Subject: Re: Oldest use of tire gauges on bicycles?
|
On 12 Oct 2007 11:22:18 GMT, jobst.brandt@stanfordalumni.org wrote:
>Ryan Cousineau <rcousine@sfu.ca> writes:
[snip]
>> At the risk of verging from mediation to taunting, I need some
>> numbers here: how many PSI does the tire have to be down before it's
>> detectable? Could you pass Carl's proposed double-blind
>> pressure-testing-test?
>
>I usually inflate to 100psi with my floor pump and find less than
>90psi detectably softer. I don't care if it is between 85 and 100.
>That's good enough.
[snip]
Dear Jobst,
Boy, that 85-100 psi range would have made things a lot clearer!
I wonder if Tom is talking about the same 85~100 psi ballpark?
For what it's worth, when my weekly pump check shows that my 110 psi
Slime tubes have dropped 10-15 psi, I pull them out and patch their
slow leaks. Down at 85 psi, I expect impact flats on my 25 mm tires,
but that's due to the way that I ride and a few sharp bumps on my
route.
Of course, tire pressure changes much more often for me than for many
posters because I ride where goathead thorns often cause slow leaks:
http://i24.tinypic.com/de5nao.jpg
That's my box of 21 spare Slime tubes, with my most recent flat
showing 6 patches. Some patches are close together, but that's just
luck--the punctures came on separate rides.
Two more patched Slime tubes are in my tires, plus two more in my
frame bag, and I just cycle through the 25 tubes. I originally had 36
tubes, but I've thrown 11 away because they were too badly torn in
non-goathead flats involving Russian olive thorns or bead blow-offs:
http://i19.tinypic.com/53r4dp0.jpg
Or I threw them away because they were punctured too high up next to
the valve. Imagine this goathead next to the valve:
http://i18.tinypic.com/2gtpxd2.jpg
The plastic baggies make the tubes much easier to slide in and out of
the frame-bag, which I do often enough to make the convenience
attractive.
My other two frame-bag spare tubes are deep-rim long-valve non-Slime
tubes, partly to save space and partly in case I meet a gorgeous woman
with a deep aero rim and a flat tire. I haven't met her yet, but I
have used all four spare tubes and a glueless Park patch on a single
ride.
Cheers,
Carl Fogel
|
| | | | | | | | | | | | | | |
Date: 12 Oct 2007 09:33:18
From: Bill Sornson
Subject: Re: Oldest use of tire gauges on bicycles?
|
jobst.brandt@stanfordalumni.org wrote:
> Ryan Cousineau <rcousine@sfu.ca> writes:
>
>>>>>> At least four posters have indicated here and elsewhere that
>>>>>> they think that their thumbs are pretty good at checking
>>>>>> pressure, so it seems to me that it may be possible. I'm just
>>>>>> curious what real testing would show.
>
>>>>> Carl, Carl, we're talking air in the tires...on a bicycle, psi
>>>>> not millibars. How accurate do you want to be? Geeze, I've been
>>>>> using the space bar quite a lot today, hope I can check my tires
>>>>> when I get home.
>
>>>> Dear Tom,
>
>>>> Er, probably more accurate than somewhere between 90 and 110 psi?
>
>>>> As a sidelight, I've been wondering about tire bouncers. For some
>>>> reason, I suspect that they bounce only the front tire.
>
>>> "they" come right out and say it, you think I am lying, a term that
>>> seems to escape it's severity when you apply it. If you think I
>>> like to ride on a soft rear tire, you are mistaken. I bounce first
>>> the front and then the rear of my bicycle when I head out the door.
>>> The rebound speed and sound of the wooden floor makes inflation
>>> level apparent.
>
>> Jobst: there's a big difference between "lying" and "mistaken."
>
> I don't know how much closer you can get to putting words in someone's
> mouth than Carl's suspicions about tire bouncers. I clearly stated
> that I check my tires by bouncing them (plural) and that considering
> that they might have a slow leak or some other anomaly, they should
> bounce as they did when freshly inflated.
>
> For example, on my 2000mi tour of the Alps in the summer, taking about
> three weeks, I don't pump the tires at all after leaving home in the
> USA but test to see if everything is OK by bouncing the wheels before
> taking off in the morning, just as I do at home. Saying that I
> probably only bounce the front wheel is a stretch of the imagination.
>
>>>> If not, they've developed the ability to distinguish how a rear
>>>> tire with 55% to 60% of the bike's weight bounces, as opposed to
>>>> how a front tire bounces with 45% to 40% of the weight.
>
>>> You're trying hard, but no cigar. Bouncing the front and rear of
>>> my bicycle is not alike but I can tell the difference and know what
>>> it means.
>
>> At the risk of verging from mediation to taunting, I need some
>> numbers here: how many PSI does the tire have to be down before it's
>> detectable? Could you pass Carl's proposed double-blind
>> pressure-testing-test?
>
> I usually inflate to 100psi with my floor pump and find less than
> 90psi detectably softer. I don't care if it is between 85 and 100.
> That's good enough.
>
>>>> I expect that your tires (and the tires of other thumbers and
>>>> bouncers) work fine. I'm just curious whether the accuracy is as
>>>> good as usually implied.
>
>>> Implied is that it's good enough for those who practice it.
>
>> This may be the missing link. Tire pressures don't matter that much
>> for a lot of riding.
>
> So why make such an analytical fuss about it and impute the motives of
> those who don't test and keep records of exact inflation numbers?
>
>> On my commuter, I really don't care what the tire pressures are.
>> When they dip below 60 psi, I usually notice and pump them back to
>> about 90. I use the gauge on my pump. These are, I don't know,
>> 27x1-1/4 tires, I think.
>
>> If I'm being diligent, I catch them at 65 psi.
Am I the only person who tops off his or her tires before every ride?
Bill "minimalist aerobic warmup" S.
>
>> Cyclocross and MTB disciplines, now there's where the blackest arts
>> of tire pressure choices come to the fore.
>
> That depends on how soft the average terrain is. The softer, the
> softer the tire and the more careful one must be with snake bites.
>
>
> Jobst Brandt
|
| | | | | | | | | | | | | | | |
Date: 12 Oct 2007 11:58:54
From: Michael Press
Subject: Re: Oldest use of tire gauges on bicycles?
|
In article <470fa1cf$0$25704$4c368faf@roadrunner.com >,
"Bill Sornson" <askme@ask.me > wrote:
> Am I the only person who tops off his or her tires before every ride?
Yes. I put my 25 mm tires up to 115 psi,
and let them deflate to under 90 psi. I
inflate them when cornering first gets suspicious.
--
Michael Press
|
| | | | | | | | | | | | | | | |
Date: 12 Oct 2007 13:32:55
From: A Muzi
Subject: Re: Oldest use of tire gauges on bicycles?
|
> jobst.brandt@stanfordalumni.org wrote:
>> Ryan Cousineau <rcousine@sfu.ca> writes:
snip various tire inflation protocols & analyses-
Bill Sornson wrote:
> Am I the only person who tops off his or her tires before every ride?
> Bill "minimalist aerobic warmup" S.
Every ride? How much can it lose between arriving at work and going home?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| | | | | | | | | | | | | | | | |
Date: 12 Oct 2007 15:48:43
From: Bill Sornson
Subject: Re: Oldest use of tire gauges on bicycles?
|
A Muzi wrote:
> Bill Sornson wrote:
>> Am I the only person who tops off his or her tires before every ride?
>> Bill "minimalist aerobic warmup" S.
> Every ride? How much can it lose between arriving at work and going
> home?
Work? My office is about 50 feet from my bed. My bikes another 80-90 feet
from there. I ride to get AWAY from work :)
Bill "back from a windy 50...radial wire flat about 3 miles from home" S.
PS: Pump 'em up, top 'em off. Why not?
|
| | | | | |
Date: 10 Oct 2007 02:23:55
From: Ben C
Subject: Re: Oldest use of tire gauges on bicycles?
|
On 2007-10-10, carlfogel@comcast.net <carlfogel@comcast.net > wrote:
[...]
> My version of the thumb-test is to look at my mileage after my daily
> ride. When it creeps up to 15.120 miles or 15.123 from a normal 15.095
> to 15.105 on my trusty $10 Schwinn cyclocomputer, I know that my front
> tire is losing air, probably from tiny pinholes semi-sealed by Slime,
> enough to add about a dozen extra wheel revolutions to my daily ride.
>
> (Talk about cheap, ridiculous accuracy!)
Sorry to be dense, but are you pulling our legs? Surely you get more
variance than that anyway-- depending on how many snakes you have to
dodge for one thing.
And why would a soft tyre give you a higher apparent mileage anyway?
One might expect the opposite as the radius has been reduced.
[...]
> Hmmm . . . I have a bike, an air pump with a gauge, and a concrete
> floor to bounce it off. I wonder what the actual difference is between
> a tire with 110 psi, 100, 90, and 80? Or how far a thumb-shaped pad
> with a heavy weight will sink into a 700x25 tire at those pressures,
> as measured by a dial gauge?
You did some thumb-test tests before. I'm fairly sure (even more sure
now that I have a real pressure gauge as well) that fatter tyres feel
harder at lower pressures than thinner ones. So pump up all tyres until
they feel right to the thumb, and never mind about psi or what it says
on the sidewall.
I'll leave it at that for now rather than theorize about casing-tension.
http://groups.google.co.uk/group/rec.bicycles.tech/msg/1bf12937a4e9c33b
and
http://groups.google.co.uk/group/rec.bicycles.tech/msg/43dbe855b4e86e64
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Date: 10 Oct 2007 02:43:07
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Wed, 10 Oct 2007 02:23:55 -0500, Ben C <spamspam@spam.eggs > wrote:
>On 2007-10-10, carlfogel@comcast.net <carlfogel@comcast.net> wrote:
>[...]
>> My version of the thumb-test is to look at my mileage after my daily
>> ride. When it creeps up to 15.120 miles or 15.123 from a normal 15.095
>> to 15.105 on my trusty $10 Schwinn cyclocomputer, I know that my front
>> tire is losing air, probably from tiny pinholes semi-sealed by Slime,
>> enough to add about a dozen extra wheel revolutions to my daily ride.
>>
>> (Talk about cheap, ridiculous accuracy!)
>
>Sorry to be dense, but are you pulling our legs? Surely you get more
>variance than that anyway-- depending on how many snakes you have to
>dodge for one thing.
>
>And why would a soft tyre give you a higher apparent mileage anyway?
>One might expect the opposite as the radius has been reduced.
>
>[...]
>> Hmmm . . . I have a bike, an air pump with a gauge, and a concrete
>> floor to bounce it off. I wonder what the actual difference is between
>> a tire with 110 psi, 100, 90, and 80? Or how far a thumb-shaped pad
>> with a heavy weight will sink into a 700x25 tire at those pressures,
>> as measured by a dial gauge?
>
>You did some thumb-test tests before. I'm fairly sure (even more sure
>now that I have a real pressure gauge as well) that fatter tyres feel
>harder at lower pressures than thinner ones. So pump up all tyres until
>they feel right to the thumb, and never mind about psi or what it says
>on the sidewall.
>
>I'll leave it at that for now rather than theorize about casing-tension.
>
>http://groups.google.co.uk/group/rec.bicycles.tech/msg/1bf12937a4e9c33b
>
>and
>
>http://groups.google.co.uk/group/rec.bicycles.tech/msg/43dbe855b4e86e64
Dear Ben,
It certainly is ridiculous how little my mileage varies, but . . .
Daily mileage from September 1st (more available according to popular
demand), starting from second expansion joint in my driveway, magnet
just past sensor, u-turn at turnoff at top of hill west of town,
stopping at garage door crack:
15.097 September 1st pumped front tire
15.101
15.097
15.101
15.101
15.108
15.108
*15.125 !!!
15.104 pumped front before ride, seemed okay, too lazy to check
15.112
15.097 pumped front before ride, note reduction
15.102
15.108
*15.122 !!! false alarm, traffic at u-turn, so I went further
15.102
15.106
15.101
15.112 flat rear today
*15.128 !!!
15.1 replaced slow leak front before ride
15.105
15.11
*15.121 !!!
15.125 pumped instead of fixing, lazy
15.109
15.121 !!! flat rear today
15.116 replaced slow leak front before ride
*15.122 !!! worrisome, but couldn't find a new leak
15.11 pumped front again
15.088 overpumped front to 120 psi, note low distance
15.105
15.105
15.1
15.102
15.118
15.114
15.113
15.11
15.113 Tuesday Oct. 9th
As for why a softer tire gives a greater mileage, the tire squishes
more at the contact patch and gives an effectively smaller radius.
In crude terms, the contact patch takes a short-cut, a chord across
the inside of the normal tire. The larger the contact patch, the
greater the chord, and the more distance cut off each spin of the
tire.
Thus if the cyclometer is set so that a normal tire gives 1,000
revolutions for a real mile of road, the softer and effectively
smaller tire has to make 1,000+ revolutions to cover the same real
mile of road (more turns) and will claim that you rode a little more
than a mile.
The Schwinn $10 model reads in thousandths of a mile, which is no
tribute to a superior instrument--they just increased the normal
2-digit reading to 3 digits, so that it shows damned near 1 digit per
spin of the wheel. That is, it's set to show 5.28 feet per hundredth
of a mile on a tire circumference that I leave at the factory 2120 mm,
which is just under 7 feet. Any cyclometer could do the same thing,
since it just increments a number every time the wheel spins once and
then increments the display according to how many digits are allowed
on the screen.
There is some variation, probably due to weaving and cutting or
widening corners, but obviously not much. Former trials riders tend to
stick closer to their lines than normal people, and I'm appalled by
people who ride on the wrong side of the bike path.
As for bounce-testing for pressure, I'm curious about how to even
perform the test. I suspect that there will be very little difference
in bounce height between say 100 and 110 psi and haven't figured out
how to see how high the tire bounces when dropped from the same
height. There may be a clever trick, but most of the bounce tests that
I've seen (usually involving basketballs dropped from much greater
heights) involve a kid and a father with a video camera, so I'm
stymied.
A thumb-shaped dingus, a weight, and a dial indicator sound much
easier to measure against a tire pumped to 80-90-100-110-120 psi. I do
have a handy model of a thumb on each hand, weights, dial indicator,
and floor pump.
Cheers,
Carl Fogel
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Date: 09 Oct 2007 23:21:14
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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Tom Nakashima writes:
>> Your only possible excuse is that you own one of those modern
>> degraded bi-cycles equipped with the mysterious foreign "Presta"
>> air valves, to which no known pressure gauge can be fitted, so you
>> are making a dubious virtue of a painful necessity.
>> Should I discover a pre-1920 Presta valve tire gauge, I shall
>> immediately inform you, but I've looked through quite a few
>> catalogues so far without finding one.
> What's wrong with using the tried & true, thumb gauge?
...or for that matter bouncing the bicycle's front an rear tire on the
floor while wheeling it out the door for a ride. That's how I detect
whether a tire needs pumping, but because I have a double acting floor
pump on which the delivery stroke varies insignificantly with
pressure, I watch the gauge, something I don't need when using my
Silca frame pump on the road after fixing a flat.
In the days of yore we had only the Silca frame pump for Presta valves
and force required for 90-100psi was well known. Then reservoir floor
pumps came along that had a surge tank between pump and tire that
covered for the leaky connection to an externally threaded valve stem.
These pumps made a big popssss sound when disconnected from the valve
stem, a sound heard often at the velodrome where a frame pump didn't
suffice anyway.
Jobst Brandt
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Date: 09 Oct 2007 01:07:24
From:
Subject: Re: Oldest use of tire gauges on bicycles?
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On Mon, 08 Oct 2007 15:03:06 -0600, carlfogel@comcast.net wrote:
>I'm wondering when tire gauges became widely used for bicycles, which
>is an awfully vague question.
>
>After all, Frank Krygowski has pointed out that tire gauges may not be
>all that widely used even today.
>
>So I'm just looking for early references to bicyclists using tire
>gauges, recommended bicycle air pressures, pros using tire gauges, or
>bike catalogues trying to sell tire gauges.
>
>I got absolutely nowhere trying to find ancient Presta valve tire
>gauges. Everything around 1900 seems to be Schrader. Indeed, most of
>the antique gauges were made by Schader.
>
>Ebay turned out to have lots of old tire gauges with pictures. The
>dates are iffy, since they often mention two or three patents from
>1893 to 1923.
>
>The old gauges seem to come in two ranges, 10-50 psi for balloon tires
>versus 20-120 psi for more modern-style tires. As far as I can tell,
>both kinds of tires meant car tires.
>
>I grabbed these pictures from auctions:
>
>1909 Schrader pencil tire gauge and case:
> http://i21.tinypic.com/5xsgba.jpg
>
>1911 U.S. Gauge Company dial gauge to 50 psi marked for balloon tires:
> http://i21.tinypic.com/149cq2o.jpg
>
>Early Schrader 10-50 psi and Wein 20-120 psi pencil gauges:
> http://i20.tinypic.com/2eoy9me.jpg
>
>An early Schrader, at least 30-110 psi:
> http://i23.tinypic.com/11vk80k.jpg
>
>Here's a full-page 1926 Schrader tire gauge ad from the Saturday
>Evening Post:
> http://i21.tinypic.com/1jt5cl.jpg
>
>As a sidelight, Wikipedia suggests that we may be fooling ourselves on
>some gauges:
>
>"The accuracy of a typical mechanical gauge as shown is +/- 3 PSI.
>Higher accuracy gauges with +/- 1 PSI accuracy can also be obtained."
>
> http://en.wikipedia.org/wiki/Tire-pressure_gauge
>
>And for those who wonder about low-pressure motorcycle trials tire
>gauges, here's one from the early 1970's:
>
> http://i21.tinypic.com/15rlis4.jpg
>
>These low-pressure 0-20 psi gauges are popular nowadays for inflating
>huge low-pressure ATV tires.
>
>Drat! Now I'm wondering about the earliest use of tension gauges for
>bicycle, motorcycle, or car spokes! Jobst shows one in "The Bicycle
>Wheel" in 1981.
>
>Cheers,
>
>Carl Fogel
Aha! At least back to 1919!
http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+36%2Ejpg
Upper right, a Schrader tire pressure gauge appears in a bicycle
(well, bicycle and sewing machine) catalogue, along with the comment
that "Average pressure for bicycle tires is 40 pounds."
The Black Beauty Company of Philadelphia sold bikes with 28 inch
wheels and tires 1 & 3/8 inches wide to 1 & 5/8 inches wide:
"The Triangle Trusty Tread, as the name indicates, assurs safety and
comfort to riders on slippery and oily roads. The tread is so designed
that it is impossible for the tire to skid. The small pockets in the
triangle create a vacuum which holds the tire fast to the slippery
roads."
The picture of the other brand of tire on that page, the Securo, is
worth a look because the tread is an endless series of swastikas.
http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+22%2Ejpg
The company embodied almost every marketing excess imaginable, with
lots of models rising in $2 increments as more nonsense was added,
right up to the top-of-the-line $54 Champion with its blue tires,
fake-front-motorcycle-strut, and double-top-tube enclosing a
"motorcycle" tank for carrying tools:
http://www.nostalgic.net/index.asp?S=arc/ScannedLit/1919%20black%20beauty/Black+Beauty+pg+21%2Ejpg
As for tension gauges, searching the U.S. patents has revealed none
for bicycle spokes earlier than this 1976 design:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=3949604.PN.&OS=PN/3949604&RS=PN/3949604
The image is worth a look--it's nothing like modern designs.
Backtracking the references to other patents cited shows only tension
gauges for sailboat cables and guy wires.
I met the same dead ends with the later and different Hjertberg 1985
patent:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=25&p=1&f=G&l=50&d=PALL&S1=((((tension+AND+gauge)+AND+spoke)+AND+bicycle).BSUM.+or+(((tension+AND+gauge)+AND+spoke)+AND+bicycle).DETD.+or+(((tension+AND+gauge)+AND+spoke)+AND+bicycle).DRWD.)&OS=spec/(tension+and+gauge+and+spoke+and+bicycle)&RS=SPEC/(((tension+AND+gauge)+AND+spoke)+AND+bicycle)
Cheers,
Carl Fogel
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