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Main
Date: 28 Oct 2007 13:02:27
From: Marian
Subject: Making it fit
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About a week ago I asked "will it fit" about a badly abused road
road bike I saw by the side of the road in Haikou.
The answer is "no."
My requirements:
1) lugged steel
2) clearance sufficient for wide tires _and_ mud fenders
3) ability to mount downtube shifters
4) long chainstays for carrying luggage
5) handlebars level or nearly level with saddle
6) rack eyelets front
7) rack eyelets back
While it looked good at a glance this bike fails on 3 and 6 and is
more rusty than I originally thought. While I think it's probably
only superficial rust, I'd rather not take the chance.
I can find 1, 2, 4, 5, and 7 easy. But, if they have the necessary
stuff for shifters they rarely come with 3 and almost never come with
6.
A frame ordered from the bike shop can give me 2 through 7 but only
in tig welded steel.
But all is not lost!
There's a framebuilder in Shenzhen. Jan Kole. Who works in steel.
Who has lugged steel as an option. And who, compared to every other
custom steel frame I've seen anywhere on the internet, has a
ridiculously low price for in-country customers. We're talking not
all that significantly more expensive than the frame my wrench thinks
he might be able to get for me.
I've got a choice between CrMo and Columbus Spirit tubing but no
explanation of what the difference would be.
Can someone explain?
I've also been asked to clarify how long I want the longer chainstays
to be. But I don't really know.
Long enough so I don't have heel strike with big panniers. Long
enough so I have a long wheelbase for a cushy ride. But I can't
really figure out how to figure out what the minimum number should
be. Any suggestions?
The other decision is height of bottom bracket.
I want the handlebars about equal with the saddle. To get this I
have to have a longer top tube. Longer top tube helps with making a
longer wheelbase. I know if I have the bottom bracket on this bike
higher than on my race bike then the saddle will be higher off the
ground, so the bars will have to be higher, so the top tube will have
to be longer, so I'll have a longer wheelbase which is good, right?
But Rivendell have lower than normal bottom brackets. And brag
about it. So which is better for sport touring, higher or lower?
Another thing, I've never seen a full length frame pump on a modern
bike. Is it worth my while asking for pump pegs?
-M
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Date: 30 Oct 2007 14:27:38
From: Marian
Subject: Re: Making it fit
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On Oct 30, 11:05 am, A Muzi <a...@yellowjersey.org > wrote:
> >>> A Muzi <a...@yellowjersey.org> wrote:
> >>>> A consultation with the framebuilder is your best course.
> >>>> A lower BB height is usually desirable on a touring bike.
> >> Marian wrote:
> >>> Doing that too. In fact I got an email from him about 8 hours after
> >>> starting this thread.
> >>> But consulting with rec.bicycles.tech means I _might_ get some answers
> >>> to the questions I already have but am far more likely to end up with
> >>> NEW questions that I never even thought of and which will be good to
> >>> run by the builder.
> > A Muzi <a...@yellowjersey.org> wrote:
> >> I was hinting at a 'custom frame protocol'.
> >> You can either tell him how it oughta fit, what it needs to do, how you
> >> want it to handle, _or_ you can tell him what dimensions you want. I'd
> >> suggest the former. Especially if you are able to visit and ask him to
> >> critique your present riding position on your present bike.
> Marian wrote:
> > It is unlikely I'll be able to visit him in the near future and, being
> > as it was in a race, I really doubt he was paying much attention to my
> > posture the one time we rode together.
> > So far as I'm concerned my race bike (which is also custom) is
> > everything I want in a race bike. Every geometry change I have made
> > in the last two years has been under pressure from someone else and I
> > haven't wanted to do it because the current bike was perfectly
> > comfortable. Every time I have finally caved in to changing the
> > geometry I have been amazed at how much more comfortable the new way
> > of riding is.
> > A Muzi <a...@yellowjersey.org> wrote:
> >> Yes, some general ideas, even from r.b.t., are a good start. IMHO, if
> >> you trust him enough to build the thing you should trust his judgment
> >> based on your expectations/ physique and not second guess the exact
> >> dimensions. I think you can easily envision a set of numbers that are
> >> not physically attainable together in a closed figure!
> Marian wrote:
> > I gave some general guidelines and was specifically asked a question
> > about what I meant by longer chainstays.
> > Then when I was futzing around on the internet I found some
> > information about bottom bracket height and figured I'd check with the
> > rbt experts regarding what I'd originally said in my general
> > guidelines.
>
> To get a better feel for the numbers, compare geometry for both race
> models and genuine touring bikes in your size (note that cross bikes are
> not touring bikes!). Long chainstays help with tire clearance, mudguard
> clearance, pannier/heel clearance and shift wide range gearing better,
> altogether a Good Thing on a tourer. Examples:http://www.yellowjersey.org/POSD7G.JPGhttp://waterfordbikes.com/site/designs/t_geo.php
The easiest thing to see is that the chainstays are a lot longer, the
top tube is a lot longer, and the bottom bracket is higher. Hmm...
sounds rather a lot like my mental image of what needed to be done to
make my perfect race bike into a perfect touring bike.
Waterford doesn't use 700c tires on a touring bike in my size.
However, seeing as I already have a pair of very nice 700c wheels with
105 hubs I think I'll stick to that wheel size.
-M
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Date: 30 Oct 2007 13:55:31
From: A Muzi
Subject: Re: Making it fit
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>>>>> A Muzi <a...@yellowjersey.org> wrote:
>>>>>> A consultation with the framebuilder is your best course.
>>>>>> A lower BB height is usually desirable on a touring bike.
>>>> Marian wrote:
>>>>> Doing that too. In fact I got an email from him about 8 hours after
>>>>> starting this thread.
>>>>> But consulting with rec.bicycles.tech means I _might_ get some answers
>>>>> to the questions I already have but am far more likely to end up with
>>>>> NEW questions that I never even thought of and which will be good to
>>>>> run by the builder.
>>> A Muzi <a...@yellowjersey.org> wrote:
>>>> I was hinting at a 'custom frame protocol'.
>>>> You can either tell him how it oughta fit, what it needs to do, how you
>>>> want it to handle, _or_ you can tell him what dimensions you want. I'd
>>>> suggest the former. Especially if you are able to visit and ask him to
>>>> critique your present riding position on your present bike.
>> Marian wrote:
>>> It is unlikely I'll be able to visit him in the near future and, being
>>> as it was in a race, I really doubt he was paying much attention to my
>>> posture the one time we rode together.
>>> So far as I'm concerned my race bike (which is also custom) is
>>> everything I want in a race bike. Every geometry change I have made
>>> in the last two years has been under pressure from someone else and I
>>> haven't wanted to do it because the current bike was perfectly
>>> comfortable. Every time I have finally caved in to changing the
>>> geometry I have been amazed at how much more comfortable the new way
>>> of riding is.
>>> A Muzi <a...@yellowjersey.org> wrote:
>>>> Yes, some general ideas, even from r.b.t., are a good start. IMHO, if
>>>> you trust him enough to build the thing you should trust his judgment
>>>> based on your expectations/ physique and not second guess the exact
>>>> dimensions. I think you can easily envision a set of numbers that are
>>>> not physically attainable together in a closed figure!
>> Marian wrote:
>>> I gave some general guidelines and was specifically asked a question
>>> about what I meant by longer chainstays.
>>> Then when I was futzing around on the internet I found some
>>> information about bottom bracket height and figured I'd check with the
>>> rbt experts regarding what I'd originally said in my general
>>> guidelines.
> A Muzi <a...@yellowjersey.org> wrote:
>> To get a better feel for the numbers, compare geometry for both race
>> models and genuine touring bikes in your size (note that cross bikes are
>> not touring bikes!). Long chainstays help with tire clearance, mudguard
>> clearance, pannier/heel clearance and shift wide range gearing better,
>> altogether a Good Thing on a tourer. Examples:
>> http://www.yellowjersey.org/POSD7G.JPG
>> http://waterfordbikes.com/site/designs/t_geo.php
Marian wrote:
> The easiest thing to see is that the chainstays are a lot longer, the
> top tube is a lot longer, and the bottom bracket is higher. Hmm...
> sounds rather a lot like my mental image of what needed to be done to
> make my perfect race bike into a perfect touring bike.
>
> Waterford doesn't use 700c tires on a touring bike in my size.
> However, seeing as I already have a pair of very nice 700c wheels with
> 105 hubs I think I'll stick to that wheel size.
Waterford's _suggested_ geometry uses small wheels in small sizes. Since
each is a custom for one rider it can be as you desire.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 29 Oct 2007 13:51:54
From: Marian
Subject: Re: Making it fit
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On Oct 29, 9:21 am, A Muzi <a...@yellowjersey.org > wrote:
> > A Muzi <a...@yellowjersey.org> wrote:
> >> A consultation with the framebuilder is your best course.
> >> A lower BB height is usually desirable on a touring bike.
> Marian wrote:
> > Doing that too. In fact I got an email from him about 8 hours after
> > starting this thread.
>
> > But consulting with rec.bicycles.tech means I _might_ get some answers
> > to the questions I already have but am far more likely to end up with
> > NEW questions that I never even thought of and which will be good to
> > run by the builder.
>
> I was hinting at a 'custom frame protocol'.
> You can either tell him how it oughta fit, what it needs to do, how you
> want it to handle, _or_ you can tell him what dimensions you want. I'd
> suggest the former. Especially if you are able to visit and ask him to
> critique your present riding position on your present bike.
It is unlikely I'll be able to visit him in the near future and, being
as it was in a race, I really doubt he was paying much attention to my
posture the one time we rode together.
So far as I'm concerned my race bike (which is also custom) is
everything I want in a race bike. Every geometry change I have made
in the last two years has been under pressure from someone else and I
haven't wanted to do it because the current bike was perfectly
comfortable. Every time I have finally caved in to changing the
geometry I have been amazed at how much more comfortable the new way
of riding is.
> Yes, some general ideas, even from r.b.t., are a good start. IMHO, if
> you trust him enough to build the thing you should trust his judgment
> based on your expectations/ physique and not second guess the exact
> dimensions. I think you can easily envision a set of numbers that are
> not physically attainable together in a closed figure!
I gave some general guidelines and was specifically asked a question
about what I meant by longer chainstays.
Then when I was futzing around on the internet I found some
information about bottom bracket height and figured I'd check with the
rbt experts regarding what I'd originally said in my general
guidelines.
-M
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Date: 29 Oct 2007 21:05:41
From: A Muzi
Subject: Re: Making it fit
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>>> A Muzi <a...@yellowjersey.org> wrote:
>>>> A consultation with the framebuilder is your best course.
>>>> A lower BB height is usually desirable on a touring bike.
>> Marian wrote:
>>> Doing that too. In fact I got an email from him about 8 hours after
>>> starting this thread.
>>> But consulting with rec.bicycles.tech means I _might_ get some answers
>>> to the questions I already have but am far more likely to end up with
>>> NEW questions that I never even thought of and which will be good to
>>> run by the builder.
> A Muzi <a...@yellowjersey.org> wrote:
>> I was hinting at a 'custom frame protocol'.
>> You can either tell him how it oughta fit, what it needs to do, how you
>> want it to handle, _or_ you can tell him what dimensions you want. I'd
>> suggest the former. Especially if you are able to visit and ask him to
>> critique your present riding position on your present bike.
Marian wrote:
> It is unlikely I'll be able to visit him in the near future and, being
> as it was in a race, I really doubt he was paying much attention to my
> posture the one time we rode together.
> So far as I'm concerned my race bike (which is also custom) is
> everything I want in a race bike. Every geometry change I have made
> in the last two years has been under pressure from someone else and I
> haven't wanted to do it because the current bike was perfectly
> comfortable. Every time I have finally caved in to changing the
> geometry I have been amazed at how much more comfortable the new way
> of riding is.
> A Muzi <a...@yellowjersey.org> wrote:
>> Yes, some general ideas, even from r.b.t., are a good start. IMHO, if
>> you trust him enough to build the thing you should trust his judgment
>> based on your expectations/ physique and not second guess the exact
>> dimensions. I think you can easily envision a set of numbers that are
>> not physically attainable together in a closed figure!
Marian wrote:
> I gave some general guidelines and was specifically asked a question
> about what I meant by longer chainstays.
> Then when I was futzing around on the internet I found some
> information about bottom bracket height and figured I'd check with the
> rbt experts regarding what I'd originally said in my general
> guidelines.
To get a better feel for the numbers, compare geometry for both race
models and genuine touring bikes in your size (note that cross bikes are
not touring bikes!). Long chainstays help with tire clearance, mudguard
clearance, pannier/heel clearance and shift wide range gearing better,
altogether a Good Thing on a tourer. Examples:
http://www.yellowjersey.org/POSD7G.JPG
http://waterfordbikes.com/site/designs/t_geo.php
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 29 Oct 2007 04:50:15
From: Michael Press
Subject: Re: Making it fit
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In article
<1193576547.258300.45000@t8g2000prg.googlegroups.com >,
Marian <marian.rosenberg@gmail.com > wrote:
> I've also been asked to clarify how long I want the longer chainstays
> to be. But I don't really know.
> Long enough so I don't have heel strike with big panniers. Long
> enough so I have a long wheelbase for a cushy ride. But I can't
> really figure out how to figure out what the minimum number should
> be. Any suggestions?
450 mm
--
Michael Press
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Date: 28 Oct 2007 23:04:19
From: Marian
Subject: Re: Making it fit
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On Oct 29, 5:02 am, A Muzi <a...@yellowjersey.org > wrote:
> A consultation with the framebuilder is your best course.
> A lower BB height is usually desirable on a touring bike.
Doing that too. In fact I got an email from him about 8 hours after
starting this thread.
But consulting with rec.bicycles.tech means I _might_ get some answers
to the questions I already have but am far more likely to end up with
NEW questions that I never even thought of and which will be good to
run by the builder.
-M
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Date: 28 Oct 2007 19:21:45
From: A Muzi
Subject: Re: Making it fit
|
> A Muzi <a...@yellowjersey.org> wrote:
>> A consultation with the framebuilder is your best course.
>> A lower BB height is usually desirable on a touring bike.
Marian wrote:
> Doing that too. In fact I got an email from him about 8 hours after
> starting this thread.
>
> But consulting with rec.bicycles.tech means I _might_ get some answers
> to the questions I already have but am far more likely to end up with
> NEW questions that I never even thought of and which will be good to
> run by the builder.
I was hinting at a 'custom frame protocol'.
You can either tell him how it oughta fit, what it needs to do, how you
want it to handle, _or_ you can tell him what dimensions you want. I'd
suggest the former. Especially if you are able to visit and ask him to
critique your present riding position on your present bike.
Yes, some general ideas, even from r.b.t., are a good start. IMHO, if
you trust him enough to build the thing you should trust his judgment
based on your expectations/ physique and not second guess the exact
dimensions. I think you can easily envision a set of numbers that are
not physically attainable together in a closed figure!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
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Date: 28 Oct 2007 16:48:19
From: Peter Cole
Subject: Re: Making it fit
|
Marian wrote:
> I've also been asked to clarify how long I want the longer chainstays
> to be. But I don't really know.
> Long enough so I don't have heel strike with big panniers. Long
> enough so I have a long wheelbase for a cushy ride. But I can't
> really figure out how to figure out what the minimum number should
> be. Any suggestions?
I think 45cm is a good number. There's no real danger in going a little
too long. Besides pannier clearance, you also want fender & tire
clearance. This usually also affects what kind of brakes you want, too.
>
> The other decision is height of bottom bracket.
> I want the handlebars about equal with the saddle. To get this I
> have to have a longer top tube. Longer top tube helps with making a
> longer wheelbase. I know if I have the bottom bracket on this bike
> higher than on my race bike then the saddle will be higher off the
> ground, so the bars will have to be higher, so the top tube will have
> to be longer, so I'll have a longer wheelbase which is good, right?
Long chain stays is the easier way to get a longer wheelbase.
> But Rivendell have lower than normal bottom brackets. And brag
> about it. So which is better for sport touring, higher or lower?
Generally lower. The trade off with BB height is the risk of pedal
strike vs. the ease of starting & stopping. Low BB makes it easier to
"dab" with one foot at a stop while sitting in the saddle. The pedal
strike issue is more of a concern with long cranks. Low BB's don't make
the bike more "stable", they actually make it a little less, though the
difference is trivial.
> Another thing, I've never seen a full length frame pump on a modern
> bike. Is it worth my while asking for pump pegs?
Sure, if you're doing a custom, I would. You might consider mounting the
pump behind the seat post (on the chain stay), although your frame might
be too small. I don't like under-top tube pump mounts because it can
make carrying the bike awkward.
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Date: 28 Oct 2007 13:14:16
From: Hank Wirtz
Subject: Re: Making it fit
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On Oct 28, 9:55 am, nmp <addr...@is.invalid > wrote:
> Marian wrote:
> > My requirements:
>
> > 1) lugged steel
> > 2) clearance sufficient for wide tires _and_ mud fenders 3) ability to
> > mount downtube shifters 4) long chainstays for carrying luggage 5)
> > handlebars level or nearly level with saddle 6) rack eyelets front
> > 7) rack eyelets back
>
> > While it looked good at a glance this bike fails on 3 and 6 and is
> > more rusty than I originally thought.
>
> WRT #3, you are aware that clamp-on shifters still exist?
True, but even among lugged steel frames, the 28.6 downtube is
endangered. Rivendell uses 32mm DTs, so does Richard Sachs, Soma,
Heron, and any other builder I can find specs for. Pacenti only makes
lugs for 32mm DTs.
If Marian is going to use this frame discussed above, then clamp-ons
are likely possible, but anything modern will require braze-on shifter
bosses to allow DT shifters.
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Date: 28 Oct 2007 16:55:59
From: nmp
Subject: Re: Making it fit
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Marian wrote:
> My requirements:
>
> 1) lugged steel
> 2) clearance sufficient for wide tires _and_ mud fenders 3) ability to
> mount downtube shifters 4) long chainstays for carrying luggage 5)
> handlebars level or nearly level with saddle 6) rack eyelets front
> 7) rack eyelets back
>
> While it looked good at a glance this bike fails on 3 and 6 and is
> more rusty than I originally thought.
WRT #3, you are aware that clamp-on shifters still exist?
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Date: 28 Oct 2007 15:04:03
From: A Muzi
Subject: Re: Making it fit
|
> Marian wrote:
>> My requirements:
>> 1) lugged steel
>> 2) clearance sufficient for wide tires _and_ mud fenders 3) ability to
>> mount downtube shifters 4) long chainstays for carrying luggage 5)
>> handlebars level or nearly level with saddle 6) rack eyelets front
>> 7) rack eyelets back
>> While it looked good at a glance this bike fails on 3 and 6 and is
>> more rusty than I originally thought.
nmp wrote:
> WRT #3, you are aware that clamp-on shifters still exist?
They do, but for modern index systems a brazed mount on a custom tourer
would be ever so much simpler. And still easily adapted to BarCon or
integrated levers later.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 28 Oct 2007 15:56:06
From: Marian
Subject: Re: Making it fit
|
On Oct 28, 10:43 pm, "Jeff" <n...@nothingX.com > wrote:
> "Marian" <marian.rosenb...@gmail.com> wrote in message
>
> news:1193576547.258300.45000@t8g2000prg.googlegroups.com...
>
> > But all is not lost!
>
> > There's a framebuilder in Shenzhen. Jan Kole. Who works in steel.
> > Who has lugged steel as an option.
>
> Almost any framebuilder could do whatever you wanted along these lines. It
> isn't a bid deal.
Very true. But very few of them live in China.
I'm insanely happy with my Habanero race bike but I'm interested in
finding out what good steel rides like and a touring bike doesn't care
about weight so I don't want to go with Mark for this bike.
> > The other decision is height of bottom bracket.
> > I want the handlebars about equal with the saddle. To get this I
> > have to have a longer top tube. Longer top tube helps with making a
> > longer wheelbase.
>
> The bb bracket height doesn't have much to do with the handlebar height in
> relation to the saddle. It has to do with the stability of the bike (for
> touring) versus cornering clearance (for serious racing). ...sounds like you
> want more of a lower bb shell, which means more drop from the horizontal
> line between the dropouts.
>From the stem chart at http://www.habcycles.com/fitting.html I
understand that, if I wanted to keep the same saddle to bars reach as
I have on my race bike and I were to raise the handlebars 5cm I would
need to make the top tube 1.5cm longer to compensate.
Furthermore if I raise the bottom bracket higher than it is on the
race bike and keep the same saddle to bottom bracket ratio then the
saddle will be higher off the ground.
If the bottom bracket (and thus the saddle) were 2cm higher, the
handlebars would need to be 2cm higher and the top tube would need to
be another .6cm longer.
The compact geometry top tube on my race bike is 48.9cm for an
effective 48cm.
> Handlebar height - at least the maximum, especially for the newer aheadset
> type forks - is determined by combination of seattube length (yes, seattube
> length), the slope of the top-tube (in the past, horizontal, and now often
> sloping), and the height of the headtube over the top tube). For touring,
> you can get a slightly larger frame as traditionally measured by the
> seattube length. A higher seattube will place the headtube higher with a
> traditional horizontal toptube, and even higher with a sloping toptube. If
> the headtube extends a bit higher than normal above the top tube, you'll be
> able to get the bars even higher without the use of excessive spacers.
Umm yeah. What you said. That's basically what I want. A larger
frame with higher handlebars.
Also since it's an option and since I'm already doing the retro lugged
steel thing I was actually thinking of getting a threaded headset.
> Serotta, for example, makes their headtubes extend a bit higher (e.g., about
> 2 cm) than other frames for this reason. The lenght of the top tube has no
> direct effect on the bar height other than the fact that standard geometry
> will make all of the other measurements that I've mentioned also larger with
> a longer top tube. ...but the top tube length is likely the single most
> important measurement for bike comfort. For comfort, you really need the
> correct top tube lenght even if you have to compromise on the other
> measurements. If you are getting a custom frame made, get the builder or
> someone else to fit you.
I will be giving him my body measurements as well but since I already
have a custom bike which I am very satisfied with it seems logical to
start from that.
> You can only adjust the distance from the saddle to
> the bars a bit using different stem lengths - from about 90mm to 130 or
> 140mm. If your top tube is to short or long you might not be able to get the
> proper stem length to enable comfort. The wheelbase should be adjusted with
> things other than the toptube length.
Like chainstay length, right?
> >I know if I have the bottom bracket on this bike
> > higher than on my race bike then the saddle will be higher off the
> > ground, so the bars will have to be higher, so the top tube will have
> > to be longer, so I'll have a longer wheelbase which is good, right?
> > But Rivendell have lower than normal bottom brackets. And brag
> > about it. So which is better for sport touring, higher or lower?
>
> No, the saddle will be higher relative to the ground, but it doesn't matter.
> and again, the top tube length doesn't matter for bar height unless it is
> sloped. Rivendell brags about it because they are correct for touring. You
> want it lower for stability - higher keeps the pedals up so that the bike
> can be leaned more without the pedals hitting the ground for very serious
> racing.
>
> What you likely want is a sloping top tube so that you can have a shorter
> seat tube for additional stand-over clearance and still have the bars equal
> to the saddle. Since you're only putting them at the height of the saddle
> and not several inches higher, you really don't need to worry about much
> because most geometry can accomodate this okay with spacers under the stem.
Currently the only point where I have been asked for any additional
input was regarding chainstay length.
I originally asked for a bottom bracket slightly higher than on my
race bike with the idea that I might use this bike for cyclocross and
with the memory of a mountain bike I got rid of about six months ago
that I quite liked (except for being waaaaay too large for me) which
had a very very high bottom bracket.
Reading the Rivendell website I saw the bit about lower than normal
bottom brackets and it got me thinking, "why?".
Musing on bottom brackets I was thinking (without knowing why a lower
one might or might not be good) that the main advantage to a high
bottom bracket is that it forces the other measurements to change for
the bigger and makes the wheelbase longer.
> Keep in mind that if the top tube does slope, then frame measurement are
> generally given in "virtual" measurements - what the seat tube and top tube
> lenght would be if the top tube were horizontal and the seat tube extended
> to that horizontal line of the now horizontal toptube. So discuss the
> geometry in "virtual terms" and then ask for a sloping top tube to increase
> standover clearance.
Of course.
> > Another thing, I've never seen a full length frame pump on a modern
> > bike. Is it worth my while asking for pump pegs?
>
> ...can't hurt, but those full length pumps aren't used that much anymore. I
> use a combination of small hand pump and co2.
It's going to be the tourer not the race bike. CO2 is silly for a
tour bike.
-M
|
| | |
Date: 29 Oct 2007 00:02:02
From: Jeff
Subject: Re: Making it fit
|
"Marian" <marian.rosenberg@gmail.com > wrote in message
news:1193586966.168502.64130@y27g2000pre.googlegroups.com...
> On Oct 28, 10:43 pm, "Jeff" <n...@nothingX.com> wrote:
>
>>From the stem chart at http://www.habcycles.com/fitting.html I
> understand that, if I wanted to keep the same saddle to bars reach as
> I have on my race bike and I were to raise the handlebars 5cm I would
> need to make the top tube 1.5cm longer to compensate.
Okay, I understand what you mean.
> Furthermore if I raise the bottom bracket higher than it is on the
> race bike and keep the same saddle to bottom bracket ratio then the
> saddle will be higher off the ground.
>
> If the bottom bracket (and thus the saddle) were 2cm higher, the
> handlebars would need to be 2cm higher and the top tube would need to
> be another .6cm longer.
Okay, but you normally don't measure such things from the ground. The
tradition has been to measure from the center of the bb shell.
So if you raised the bb, had the same seattube length (and angle), had a
horizontal top tube, you would get the same handlebar height with the same
amount of headset spacers and stem angle.
> If the headtube extends a bit higher than normal above the top tube,
> you'll be
>> able to get the bars even higher without the use of excessive spacers.
> Umm yeah. What you said. That's basically what I want. A larger frame
> with higher handlebars.
So the other option is to keep the seattube a slightly smaller size and put
a bit extra length to the headtube where it extends over the toptube. Again,
serotta does this (or at least used to before the compact geometry came
along). I just bought one of their used frames and the toptube was up about
2.5 cm over the toptube. I already had a frame size slightly large for me
since I have short legs compared to my upper body, so I had that excess
removed so I could drop the handlebars to where I wanted them.
...and another option is to buy a stem that can be flipped to rise instead
of drop and also buy one for the right rise/drop angle. As I understand it,
most frame function well with stems that are 90 to 130-140 mm long, with the
larger frames working slightly better with slightly longer stems.
...sound's like you are putting a great deal of emphasis on minute top tube
length differences and other measurements when the stem length and angle can
do much more about the bar height.
--
Posted via a free Usenet account from http://www.teranews.com
|
| | |
Date: 28 Oct 2007 15:02:02
From: A Muzi
Subject: Re: Making it fit
|
Marian wrote:
> On Oct 28, 10:43 pm, "Jeff" <n...@nothingX.com> wrote:
>> "Marian" <marian.rosenb...@gmail.com> wrote in message
>>
>> news:1193576547.258300.45000@t8g2000prg.googlegroups.com...
>>
>>> But all is not lost!
>>> There's a framebuilder in Shenzhen. Jan Kole. Who works in steel.
>>> Who has lugged steel as an option.
>> Almost any framebuilder could do whatever you wanted along these lines. It
>> isn't a bid deal.
>
> Very true. But very few of them live in China.
>
> I'm insanely happy with my Habanero race bike but I'm interested in
> finding out what good steel rides like and a touring bike doesn't care
> about weight so I don't want to go with Mark for this bike.
>
>>> The other decision is height of bottom bracket.
>>> I want the handlebars about equal with the saddle. To get this I
>>> have to have a longer top tube. Longer top tube helps with making a
>>> longer wheelbase.
>> The bb bracket height doesn't have much to do with the handlebar height in
>> relation to the saddle. It has to do with the stability of the bike (for
>> touring) versus cornering clearance (for serious racing). ...sounds like you
>> want more of a lower bb shell, which means more drop from the horizontal
>> line between the dropouts.
>
>>From the stem chart at http://www.habcycles.com/fitting.html I
> understand that, if I wanted to keep the same saddle to bars reach as
> I have on my race bike and I were to raise the handlebars 5cm I would
> need to make the top tube 1.5cm longer to compensate.
>
> Furthermore if I raise the bottom bracket higher than it is on the
> race bike and keep the same saddle to bottom bracket ratio then the
> saddle will be higher off the ground.
>
> If the bottom bracket (and thus the saddle) were 2cm higher, the
> handlebars would need to be 2cm higher and the top tube would need to
> be another .6cm longer.
>
> The compact geometry top tube on my race bike is 48.9cm for an
> effective 48cm.
>
>> Handlebar height - at least the maximum, especially for the newer aheadset
>> type forks - is determined by combination of seattube length (yes, seattube
>> length), the slope of the top-tube (in the past, horizontal, and now often
>> sloping), and the height of the headtube over the top tube). For touring,
>> you can get a slightly larger frame as traditionally measured by the
>> seattube length. A higher seattube will place the headtube higher with a
>> traditional horizontal toptube, and even higher with a sloping toptube. If
>> the headtube extends a bit higher than normal above the top tube, you'll be
>> able to get the bars even higher without the use of excessive spacers.
>
> Umm yeah. What you said. That's basically what I want. A larger
> frame with higher handlebars.
>
> Also since it's an option and since I'm already doing the retro lugged
> steel thing I was actually thinking of getting a threaded headset.
>
>> Serotta, for example, makes their headtubes extend a bit higher (e.g., about
>> 2 cm) than other frames for this reason. The lenght of the top tube has no
>> direct effect on the bar height other than the fact that standard geometry
>> will make all of the other measurements that I've mentioned also larger with
>> a longer top tube. ...but the top tube length is likely the single most
>> important measurement for bike comfort. For comfort, you really need the
>> correct top tube lenght even if you have to compromise on the other
>> measurements. If you are getting a custom frame made, get the builder or
>> someone else to fit you.
>
> I will be giving him my body measurements as well but since I already
> have a custom bike which I am very satisfied with it seems logical to
> start from that.
>
>> You can only adjust the distance from the saddle to
>> the bars a bit using different stem lengths - from about 90mm to 130 or
>> 140mm. If your top tube is to short or long you might not be able to get the
>> proper stem length to enable comfort. The wheelbase should be adjusted with
>> things other than the toptube length.
>
> Like chainstay length, right?
>
>>> I know if I have the bottom bracket on this bike
>>> higher than on my race bike then the saddle will be higher off the
>>> ground, so the bars will have to be higher, so the top tube will have
>>> to be longer, so I'll have a longer wheelbase which is good, right?
>>> But Rivendell have lower than normal bottom brackets. And brag
>>> about it. So which is better for sport touring, higher or lower?
>> No, the saddle will be higher relative to the ground, but it doesn't matter.
>> and again, the top tube length doesn't matter for bar height unless it is
>> sloped. Rivendell brags about it because they are correct for touring. You
>> want it lower for stability - higher keeps the pedals up so that the bike
>> can be leaned more without the pedals hitting the ground for very serious
>> racing.
>>
>> What you likely want is a sloping top tube so that you can have a shorter
>> seat tube for additional stand-over clearance and still have the bars equal
>> to the saddle. Since you're only putting them at the height of the saddle
>> and not several inches higher, you really don't need to worry about much
>> because most geometry can accomodate this okay with spacers under the stem.
>
> Currently the only point where I have been asked for any additional
> input was regarding chainstay length.
>
> I originally asked for a bottom bracket slightly higher than on my
> race bike with the idea that I might use this bike for cyclocross and
> with the memory of a mountain bike I got rid of about six months ago
> that I quite liked (except for being waaaaay too large for me) which
> had a very very high bottom bracket.
>
> Reading the Rivendell website I saw the bit about lower than normal
> bottom brackets and it got me thinking, "why?".
>
> Musing on bottom brackets I was thinking (without knowing why a lower
> one might or might not be good) that the main advantage to a high
> bottom bracket is that it forces the other measurements to change for
> the bigger and makes the wheelbase longer.
>
>> Keep in mind that if the top tube does slope, then frame measurement are
>> generally given in "virtual" measurements - what the seat tube and top tube
>> lenght would be if the top tube were horizontal and the seat tube extended
>> to that horizontal line of the now horizontal toptube. So discuss the
>> geometry in "virtual terms" and then ask for a sloping top tube to increase
>> standover clearance.
>
> Of course.
>
>>> Another thing, I've never seen a full length frame pump on a modern
>>> bike. Is it worth my while asking for pump pegs?
>> ...can't hurt, but those full length pumps aren't used that much anymore. I
>> use a combination of small hand pump and co2.
>
> It's going to be the tourer not the race bike. CO2 is silly for a
> tour bike.
A consultation with the framebuilder is your best course.
A lower BB height is usually desirable on a touring bike.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
|
| |
Date: 28 Oct 2007 09:43:34
From: Jeff
Subject: Re: Making it fit
|
"Marian" <marian.rosenberg@gmail.com > wrote in message
news:1193576547.258300.45000@t8g2000prg.googlegroups.com...
> But all is not lost!
>
> There's a framebuilder in Shenzhen. Jan Kole. Who works in steel.
> Who has lugged steel as an option.
Almost any framebuilder could do whatever you wanted along these lines. It
isn't a bid deal.
> The other decision is height of bottom bracket.
> I want the handlebars about equal with the saddle. To get this I
> have to have a longer top tube. Longer top tube helps with making a
> longer wheelbase.
The bb bracket height doesn't have much to do with the handlebar height in
relation to the saddle. It has to do with the stability of the bike (for
touring) versus cornering clearance (for serious racing). ...sounds like you
want more of a lower bb shell, which means more drop from the horizontal
line between the dropouts.
Handlebar height - at least the maximum, especially for the newer aheadset
type forks - is determined by combination of seattube length (yes, seattube
length), the slope of the top-tube (in the past, horizontal, and now often
sloping), and the height of the headtube over the top tube). For touring,
you can get a slightly larger frame as traditionally measured by the
seattube length. A higher seattube will place the headtube higher with a
traditional horizontal toptube, and even higher with a sloping toptube. If
the headtube extends a bit higher than normal above the top tube, you'll be
able to get the bars even higher without the use of excessive spacers.
Serotta, for example, makes their headtubes extend a bit higher (e.g., about
2 cm) than other frames for this reason. The lenght of the top tube has no
direct effect on the bar height other than the fact that standard geometry
will make all of the other measurements that I've mentioned also larger with
a longer top tube. ...but the top tube length is likely the single most
important measurement for bike comfort. For comfort, you really need the
correct top tube lenght even if you have to compromise on the other
measurements. If you are getting a custom frame made, get the builder or
someone else to fit you. You can only adjust the distance from the saddle to
the bars a bit using different stem lengths - from about 90mm to 130 or
140mm. If your top tube is to short or long you might not be able to get the
proper stem length to enable comfort. The wheelbase should be adjusted with
things other than the toptube length.
>I know if I have the bottom bracket on this bike
> higher than on my race bike then the saddle will be higher off the
> ground, so the bars will have to be higher, so the top tube will have
> to be longer, so I'll have a longer wheelbase which is good, right?
> But Rivendell have lower than normal bottom brackets. And brag
> about it. So which is better for sport touring, higher or lower?
No, the saddle will be higher relative to the ground, but it doesn't matter.
and again, the top tube length doesn't matter for bar height unless it is
sloped. Rivendell brags about it because they are correct for touring. You
want it lower for stability - higher keeps the pedals up so that the bike
can be leaned more without the pedals hitting the ground for very serious
racing.
What you likely want is a sloping top tube so that you can have a shorter
seat tube for additional stand-over clearance and still have the bars equal
to the saddle. Since you're only putting them at the height of the saddle
and not several inches higher, you really don't need to worry about much
because most geometry can accomodate this okay with spacers under the stem.
Keep in mind that if the top tube does slope, then frame measurement are
generally given in "virtual" measurements - what the seat tube and top tube
lenght would be if the top tube were horizontal and the seat tube extended
to that horizontal line of the now horizontal toptube. So discuss the
geometry in "virtual terms" and then ask for a sloping top tube to increase
standover clearance.
> Another thing, I've never seen a full length frame pump on a modern
> bike. Is it worth my while asking for pump pegs?
...can't hurt, but those full length pumps aren't used that much anymore. I
use a combination of small hand pump and co2.
--
Posted via a free Usenet account from http://www.teranews.com
|
|
