Correct Top Tube vs. Correct Frame Size

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In article ,
Ryan Cousineau wrote:

Jasper: have you ever seen a rider on a conventional road or MTB frame
actually using an 8" riser stem, threaded or threadless? What was their
excuse?


_ Just to throw fuel on the fire, I've got one on my 80's MTB
that I converted to a drop bar touring bike. It's the apparently
no longer made SOMA threadless converter that is about 12 inches
long. Here's a picture

http://www.bti-usa.com/item.asp?item...ch=&showS ec=


Of the many differently-sized regulars on this newsgroup, the only one I
can imagine who would have call for an 8" stem, even in the worst
compact-frame-in-three-sizes circumstances, would be 6'lotsa" Chalo, and
he would probably break an 8" threaded stem. He is a great breaker of
parts and a fan of threadless stems, you know...

At some point, the frame doesn't actually fit,


_ Well, it fit me when I bought it and with the original steel
riser stem and flat bars it fits me. The length of that extension
worries me a bit, but the bike is really comfortable to ride.
I am not petite, but I am hardly Chola sized.

_BTW, I've seen this part around on a few other converted old
MTB bikes. You can get a similar amount of rise with a Nitto
Periscope stem.

_ Booker C. Bense



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In article ,
(PeteCresswell) wrote:
Per Booker C. Bense:
There are worse things, but either a very short or very long
stem will make the bike handling "different".

I have a custom hard tail that I specified an extra-long top tube on - expecting
it to help keep the front wheel down.

_ Well, I meant road bike handling, but I'm not sure why
you thought an extra long top tube would keep the front wheel
down on climbs.


It did, but my FS - which has an effective top tube over an inch shorter - is
even better in that respect.

_ My intiution would be that the longer the rear chainstay, the
easier to keep the front wheel down. However, that leads to
poorer traction on the rear wheel, if you stand to climb.

_ Booker C. Bense





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Jasper: have you ever seen a rider on a conventional road or MTB frame
actually using an 8" riser stem, threaded or threadless? What was their
excuse?

Booker C. Bense wrote:
_ Just to throw fuel on the fire, I've got one on my 80's MTB
that I converted to a drop bar touring bike. It's the apparently
no longer made SOMA threadless converter that is about 12 inches
long. Here's a picture
http://www.bti-usa.com/item.asp?item...ch=&showS ec=

Ryan Cousineau wrote:
Of the many differently-sized regulars on this newsgroup, the only one I
can imagine who would have call for an 8" stem, even in the worst
compact-frame-in-three-sizes circumstances, would be 6'lotsa" Chalo, and
he would probably break an 8" threaded stem. He is a great breaker of
parts and a fan of threadless stems, you know...
At some point, the frame doesn't actually fit,

Booker C. Bense wrote:
_ Well, it fit me when I bought it and with the original steel
riser stem and flat bars it fits me. The length of that extension
worries me a bit, but the bike is really comfortable to ride.
I am not petite, but I am hardly Chola sized.
_BTW, I've seen this part around on a few other converted old
MTB bikes. You can get a similar amount of rise with a Nitto
Periscope stem.

I'm entering this discussion late but IMHO if a dork stem
gets a guy out on his bike more often that's a good thing
right there.

Your (or my) aesthetic opinion of his bike is of secondary
import. Distant second.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

In article ,
Booker C. Bense
. stanford.edu wrote:

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In article ,
Ryan Cousineau wrote:

Jasper: have you ever seen a rider on a conventional road or MTB frame
actually using an 8" riser stem, threaded or threadless? What was their
excuse?


_ Just to throw fuel on the fire, I've got one on my 80's MTB
that I converted to a drop bar touring bike. It's the apparently
no longer made SOMA threadless converter that is about 12 inches
long. Here's a picture

http://www.bti-usa.com/item.asp?item...ch=&showS ec=

Fire away.

At some point, the frame doesn't actually fit,


_ Well, it fit me when I bought it and with the original steel
riser stem and flat bars it fits me. The length of that extension
worries me a bit, but the bike is really comfortable to ride.
I am not petite, but I am hardly Chola sized.

I may be too churlish in pointing this out, but such a change is a
pretty dramatic conversion of a bike from one use to another. So, I will
concede this: if you own an old mountain bike with the intention of
converting it to a road bike, best to have chosen one with a quill stem
.

-RjC.

--
Ryan Cousineau http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

RP10128 wrote:
I need a bike with a top tube of about 50.5 cm. To get a top tube of
that length, I need to get a frame that is one or two sizes too small.
That is, I would have to get a 49 cm. frame, whereas my inseam would
indicate a 52 cm. frame.

Stock frames from various manufacturers have various top tube lengths.
Find a stock frame with the right top tube length you want and the
right standover height.


My LBS says that it doesn't matter that the
frame is so small, but this strikes me as being counter-intuitive. Is
the LBS right?

No. The LBS is not right. No properly fitting frame requires an extra
short stem or an extra long stem to fit the rider correctly. I am
pretty sure the true reasoning of the LBS is they do not represent any
frame manufacturers with the proper length top tube in the frame size
you want. So they will try to sell you the wrong frame size and
pretend to make it fit you with an inappropriately long or short stem
and seatpost.

Should I get the correct size frame and install a very
short stem?

No. Just buy the correctly sized frame with the correct top tube
length and seat tube. You are buying new. You are not trying to make
a frame you already own fit you. You don't have to use odd stem and
seatpost lengths or rises or angles. Just find a frame with the right
top tube length and seat tube length and head tube length. Then put on
the right length stem and seatpost.

a sizing analysis based on mistakes in sizing is appropriate and useful.

In article 1n ,
A Muzi wrote:

Jasper: have you ever seen a rider on a conventional road or MTB frame
actually using an 8" riser stem, threaded or threadless? What was their
excuse?

Booker C. Bense wrote:
_ Just to throw fuel on the fire, I've got one on my 80's MTB
that I converted to a drop bar touring bike. It's the apparently
no longer made SOMA threadless converter that is about 12 inches
long. Here's a picture
http://www.bti-usa.com/item.asp?item...ch=&showS ec=

Ryan Cousineau wrote:
Of the many differently-sized regulars on this newsgroup, the only one I
can imagine who would have call for an 8" stem, even in the worst
compact-frame-in-three-sizes circumstances, would be 6'lotsa" Chalo, and
he would probably break an 8" threaded stem. He is a great breaker of
parts and a fan of threadless stems, you know...
At some point, the frame doesn't actually fit,

Booker C. Bense wrote:
_ Well, it fit me when I bought it and with the original steel
riser stem and flat bars it fits me. The length of that extension
worries me a bit, but the bike is really comfortable to ride.
I am not petite, but I am hardly Chola sized.
_BTW, I've seen this part around on a few other converted old
MTB bikes. You can get a similar amount of rise with a Nitto
Periscope stem.

I'm entering this discussion late but IMHO if a dork stem
gets a guy out on his bike more often that's a good thing
right there.

Your (or my) aesthetic opinion of his bike is of secondary
import. Distant second.

Absolutely. Heaven help us all if my aesthetic senses determined bike
usage.

My point was that threadless stems were unlikely to be an impediment to
proper bike fit. The example I was fighting against was the idea that
someone might need an 8" stem rise.

I reiterate: if you had a bike in your possession which would only fit
you by using an 8" riser stem, then go for it. But under normal
circumstances, you aren't very likely--no, you're in the territory of
being a dramatic outlier, or (as Booker suggested) you're creatively
adapting a bike outside of its usual use.

I'm not against outlandish stems per se; they're great for certain
projects. But I don't think the failure of the market to make 8"
threadless stems widely available is a serious knock against the
threadless headset.

Actually, the same site that Booker references provides me with this
nifty item:

http://www.bti-usa.com/list.asp?cat=...=&reuse=1&show
Sec=0&filter=&searchtype=&showGrp=AZ011#open

3+" threadless riser. Bolt on the mutant threadless stem of your choice
from my last posting, and you're golden.

Note again that all this references the _worst_ case scenario for a
threadless setup: a close-cut fork with no spacers. Given a long enough
uncut fork, a creative person could get a threadless stem up to whatever
ridiculous height struck their fancy.

--
Ryan Cousineau http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

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In article ,
Ryan Cousineau wrote:
In article ,
Booker C. Bense
. stanford.edu wrote:

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In article ,
Ryan Cousineau wrote:

Jasper: have you ever seen a rider on a conventional road or MTB frame
actually using an 8" riser stem, threaded or threadless? What was their
excuse?


_ Just to throw fuel on the fire, I've got one on my 80's MTB
that I converted to a drop bar touring bike. It's the apparently
no longer made SOMA threadless converter that is about 12 inches
long. Here's a picture

http://www.bti-usa.com/item.asp?item...ch=&showS ec=

Fire away.

_ In poking around, I get the impression this part was actually
made as a side effect of the short lived SOMA folding bike, which
is considered by some to be one of the better attempts at
building this kind of bike. Being able to drop the bars a
foot would certainly help in making a folding bike compact.


At some point, the frame doesn't actually fit,


_ Well, it fit me when I bought it and with the original steel
riser stem and flat bars it fits me. The length of that extension
worries me a bit, but the bike is really comfortable to ride.
I am not petite, but I am hardly Chola sized.

I may be too churlish in pointing this out, but such a change is a
pretty dramatic conversion of a bike from one use to another. So, I will
concede this: if you own an old mountain bike with the intention of
converting it to a road bike, best to have chosen one with a quill stem
.


_ Actually, if I could get a 1 inch threadless 559mm( 26" ) fork, I would
seriously consider spending the parts to switch. However, it
would likely be cheaper just to buy a Long Haul trucker frame and
move the parts over.

_ Booker C. Bense

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On Sat, 30 Jul 2005 21:27:25 GMT, Ryan Cousineau wrote:

Once you are building a non-BMX bike with an 8" rise, you are into
serious freak-show territory, threadless or not. Indeed, For a flat-bar
road or MTB that, for some reason, needed 20 cm of rise, I probably
would recommend a BMX bar.

Okay, look, most people tend to want their bar at the height of their
saddle or a little above. Then, the problem of finding people who need 8"
stems reduces to finding people with 4-5 or so inches of exposed seatpost
(given a horizontal top tube frame, of course). That's not that hard.

Also, consider the English Roadster model: those were generally sold with
stems of 6" or so even when properly sized. Now, in a country where the
average person believes the English Roadster model is the typical bike
(and who often ride undersized versions because they're the fastest
growing nation, so secondhand bikes are all too small), try to sell
threadless-stemmed bikes. It's damned hard.

Jasper

Jasper Janssen wrote:

Okay, look, most people tend to want their bar at the height of their
saddle or a little above.

???