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Date: 15 Aug 2007 18:23:28
From: Gooserider
Subject: Do complete bikes come with uncut steerers?
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I've only bought one complete bike. I bought it from an internet bike
company, and it came with the steer tube cut. I have carpal tunnel syndrome,
so I need the bars up. My last two purchases have been framesets I had built
up, so I was able to keep the steerers long. However, Raleigh has a couple
of bikes coming out that look promising---but if they're going to come with
the steer tube cut it makes dialing in my fit more expensive(meaning I'll
have to spring for a new stem). Anybody know?
Mike
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Date: 19 Aug 2007 05:00:42
From: Mike Jacoubowsky
Subject: Re: Do complete bikes come with uncut steerers?
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> I've only bought one complete bike. I bought it from an internet bike
> company, and it came with the steer tube cut. I have carpal tunnel
> syndrome, so I need the bars up. My last two purchases have been framesets
> I had built up, so I was able to keep the steerers long. However, Raleigh
> has a couple of bikes coming out that look promising---but if they're
> going to come with the steer tube cut it makes dialing in my fit more
> expensive(meaning I'll have to spring for a new stem). Anybody know?
>
> Mike
All bikes I know of from major bike companies have the steer tubes pre-cut
to a length their engineers figure to be the maximum safe height allowed.
I've spoken with engineers at Trek regarding customers with special needs
who would like to have a longer fork column; invariably, they say no, it's
not safe to have more than 4cm of exposed (acutally covered by spacers) fork
column beneath the stem.
What I don't understand is why it's OK to have a stem with a very steep
upward angle, positioning the bar quite a bit higher than normal... but it's
not OK to use a taller fork column with a lower stem (to achieve the same
position). Don't think I've asked that exact question; I'll try to remember
to next time.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
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Date: 19 Aug 2007 15:13:22
From: Dan Becker
Subject: Re: Do complete bikes come with uncut steerers?
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In article <_7Qxi.28369$RX.26898@newssvr11.news.prodigy.net >, Mike
Jacoubowsky <mikej1@ix.netcom.com > wrote:
> What I don't understand is why it's OK to have a stem with a very steep
> upward angle, positioning the bar quite a bit higher than normal... but it's
> not OK to use a taller fork column with a lower stem (to achieve the same
> position).
My instinctual reaction is that it has to do with the bending moment of
the length of steerer tube exposed above the top of the head tube. The
length of steerer tube within the head tube is restrained at both ends,
therefore there are no internal bending forces to resist. From the head
tube up, the steerer tube is acting as a vertical cantilever. Force is
applied to the stem from the weight of the rider on the handlebars
which creates a bending moment in the steerer tube.
Your former instance has a shorter cantilever to the point of applied
force, therefore less bending moment. If the length of steerer tube
exposed in the latter instance became too great, I can even see the
internal portion of the steerer tube bowing because the connection at
the top of the head tube really isn't rigid, and at some point would
begin to act as a fulcrum.
But the difference in lengths being discussed in your example is so
minimal compared to the diameter of the tube that this is probably just
a theoretical pile of crap.
FWIW,
Dan
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Date: 19 Aug 2007 08:05:07
From: Gooserider
Subject: Re: Do complete bikes come with uncut steerers?
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"Mike Jacoubowsky" <mikej1@ix.netcom.com > wrote in message
news:_7Qxi.28369$RX.26898@newssvr11.news.prodigy.net...
>> I've only bought one complete bike. I bought it from an internet bike
>> company, and it came with the steer tube cut. I have carpal tunnel
>> syndrome, so I need the bars up. My last two purchases have been
>> framesets I had built up, so I was able to keep the steerers long.
>> However, Raleigh has a couple of bikes coming out that look
>> promising---but if they're going to come with the steer tube cut it makes
>> dialing in my fit more expensive(meaning I'll have to spring for a new
>> stem). Anybody know?
>>
>> Mike
>
> All bikes I know of from major bike companies have the steer tubes pre-cut
> to a length their engineers figure to be the maximum safe height allowed.
> I've spoken with engineers at Trek regarding customers with special needs
> who would like to have a longer fork column; invariably, they say no, it's
> not safe to have more than 4cm of exposed (acutally covered by spacers)
> fork column beneath the stem.
>
> What I don't understand is why it's OK to have a stem with a very steep
> upward angle, positioning the bar quite a bit higher than normal... but
> it's not OK to use a taller fork column with a lower stem (to achieve the
> same position). Don't think I've asked that exact question; I'll try to
> remember to next time.
Thanks, Mike. I can almost understand their concern, if it's a carbon
steerer. But the two bikes I have now have steel forks and I don't think I
could bend the steerers with a hammer and a vice. :-)
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Date: 19 Aug 2007 09:11:21
From: Mike Jacoubowsky
Subject: Re: Do complete bikes come with uncut steerers?
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>> All bikes I know of from major bike companies have the steer tubes
>> pre-cut to a length their engineers figure to be the maximum safe height
>> allowed. I've spoken with engineers at Trek regarding customers with
>> special needs who would like to have a longer fork column; invariably,
>> they say no, it's not safe to have more than 4cm of exposed (acutally
>> covered by spacers) fork column beneath the stem.
>>
>> What I don't understand is why it's OK to have a stem with a very steep
>> upward angle, positioning the bar quite a bit higher than normal... but
>> it's not OK to use a taller fork column with a lower stem (to achieve the
>> same position). Don't think I've asked that exact question; I'll try to
>> remember to next time.
>
>
> Thanks, Mike. I can almost understand their concern, if it's a carbon
> steerer. But the two bikes I have now have steel forks and I don't think I
> could bend the steerers with a hammer and a vice. :-)
The steer tubes in question have been aluminum, since Trek has been
reluctant to use carbon steer tubes (they're concerned people are going to
crank down on them too hard during stem installation and cause damage). A
steel steer tube is still of concern, since they're substantially thinner
than aluminum. When we went from 1" steel to 1 1/8" aluminum, we gained
strength & overall durability (less likely to bend in a crash). Leveraging
out a 1" steer tube beyond its design, even if steel, could still result in
bad consequences. My feeling is that it's more likely to be an issue for a
bike ridden off-road though.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
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Date: 19 Aug 2007 11:16:06
From: Just A User
Subject: Re: Do complete bikes come with uncut steerers?
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Gooserider wrote:
> "Mike Jacoubowsky" <mikej1@ix.netcom.com> wrote in message
> news:_7Qxi.28369$RX.26898@newssvr11.news.prodigy.net...
>>> I've only bought one complete bike. I bought it from an internet bike
>>> company, and it came with the steer tube cut. I have carpal tunnel
>>> syndrome, so I need the bars up. My last two purchases have been
>>> framesets I had built up, so I was able to keep the steerers long.
>>> However, Raleigh has a couple of bikes coming out that look
>>> promising---but if they're going to come with the steer tube cut it makes
>>> dialing in my fit more expensive(meaning I'll have to spring for a new
>>> stem). Anybody know?
>>>
>>> Mike
>> All bikes I know of from major bike companies have the steer tubes pre-cut
>> to a length their engineers figure to be the maximum safe height allowed.
>> I've spoken with engineers at Trek regarding customers with special needs
>> who would like to have a longer fork column; invariably, they say no, it's
>> not safe to have more than 4cm of exposed (acutally covered by spacers)
>> fork column beneath the stem.
>>
>> What I don't understand is why it's OK to have a stem with a very steep
>> upward angle, positioning the bar quite a bit higher than normal... but
>> it's not OK to use a taller fork column with a lower stem (to achieve the
>> same position). Don't think I've asked that exact question; I'll try to
>> remember to next time.
>
>
> Thanks, Mike. I can almost understand their concern, if it's a carbon
> steerer. But the two bikes I have now have steel forks and I don't think I
> could bend the steerers with a hammer and a vice. :-)
>
>
Why would you TRY to bend them?
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Date: 19 Aug 2007 01:20:27
From: Tom \Johnny Sunset\ Sherman
Subject: Re: Do complete bikes come with uncut steerers?
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Mike Jacoubowsky wrote:
>> I've only bought one complete bike. I bought it from an internet bike
>> company, and it came with the steer tube cut. I have carpal tunnel
>> syndrome, so I need the bars up. My last two purchases have been framesets
>> I had built up, so I was able to keep the steerers long. However, Raleigh
>> has a couple of bikes coming out that look promising---but if they're
>> going to come with the steer tube cut it makes dialing in my fit more
>> expensive(meaning I'll have to spring for a new stem). Anybody know?
>>
>> Mike
>
> All bikes I know of from major bike companies have the steer tubes pre-cut
> to a length their engineers figure to be the maximum safe height allowed.
> I've spoken with engineers at Trek regarding customers with special needs
> who would like to have a longer fork column; invariably, they say no, it's
> not safe to have more than 4cm of exposed (acutally covered by spacers) fork
> column beneath the stem.
Is this not an argument for larger diameter steerer tubes?
> What I don't understand is why it's OK to have a stem with a very steep
> upward angle, positioning the bar quite a bit higher than normal... but it's
> not OK to use a taller fork column with a lower stem (to achieve the same
> position). Don't think I've asked that exact question; I'll try to remember
> to next time.
Hmmm..., the bike in my bedroom has a 38-cm tall stem. Of course, I do
not apply much force to it while riding.
--
Tom Sherman - Holstein-Friesland Bovinia
--
Posted via a free Usenet account from http://www.teranews.com
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Date: 15 Aug 2007 23:03:58
From: landotter
Subject: Re: Do complete bikes come with uncut steerers?
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On Aug 15, 5:23 pm, "Gooserider" <Gooseri...@mouse-potato.com > wrote:
> I've only bought one complete bike. I bought it from an internet bike
> company, and it came with the steer tube cut. I have carpal tunnel syndrome,
> so I need the bars up. My last two purchases have been framesets I had built
> up, so I was able to keep the steerers long. However, Raleigh has a couple
> of bikes coming out that look promising---but if they're going to come with
> the steer tube cut it makes dialing in my fit more expensive(meaning I'll
> have to spring for a new stem). Anybody know?
>
Most are cut AFAIK. Just get a stem raiser for $20. Not pretty, but
they work great.
http://www.deltacycle.com/product.php?g=9
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