Road Bars (26mm) in a Mountain (25.4mm) Stem = Problem?

On Sat, 02 Apr 2005 20:38:12 -0500, Steve Sr.
wrote:

Is this small diameter difference likely to cause a problem in real
life?

You bet.

I am trying to put a high angle (130 degree) stem on my road
bike to improve the fit and the high angle stems seem to only
available for Mountain bars.

Add a layer of cola can as a shim. That generally takes care of the
misfit. Make your first ride leaning hard on the hoods along a bumpy
run *expecting* the bars to pitch forward and down at any time, and if
the bars don't rotate under those conditions, you should be safe.
--
Typoes are a feature, not a bug.
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In article , Steve Sr. says...

Is this small diameter difference likely to cause a problem in real
life? I am trying to put a high angle (130 degree) stem on my road
bike to improve the fit and the high angle stems seem to only
available for Mountain bars.

Thanks,

Steve
I did this for the same reason. If the stem does not have a removable face
plate the bends in the road bar will not fit through the hole in the stem. Get
a one inch ******* (half round) file and enlarge the hole. The radius of the
file and the radius of the hole match closely so it is easy to enlarge the hole
evenly. Check you work by trying to put the bar into position in the stem. If
the stem head is aluminum you should be done in 15 minutes. Steel may take much
longer.

I was amazed that the 0.6mm difference in diameter is enough to prevent the
bends in the road bar from passing through the hole in the stem.

On Mon, 04 Apr 2005 21:49:48 -0400, Steve Sr.
wrote:

Sorry, I don't believe they make negative shims as others have already
pointed out. The bars are already bigger than the stem.

Oops, yes, that's correct. Your best bet, then, will be to find a set
of 25.4mm drop bars to fit the mtb stem. Although it would be
possible to resize the bar clamp to fit the larger diameter, this is a
tricky process when the clamp must be honed or machined with a fixed
gap retained to ensure that the clamping is successful afterwards.
It's been a good many years since I had access to the type of hone
that would do this easily, and I'd be hesitant to trust the task to
someone unfamiliar with the requirements. Accordingly, the more
rational approach is to match the sizes of the components.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Werehatrack wrote:
On Mon, 04 Apr 2005 21:49:48 -0400, Steve Sr.
wrote:

Sorry, I don't believe they make negative shims as others have
already
pointed out. The bars are already bigger than the stem.

Oops, yes, that's correct. Your best bet, then, will be to find a
set
of 25.4mm drop bars to fit the mtb stem. Although it would be
possible to resize the bar clamp to fit the larger diameter, this is
a
tricky process when the clamp must be honed or machined with a fixed
gap retained to ensure that the clamping is successful afterwards.
It's been a good many years since I had access to the type of hone
that would do this easily, and I'd be hesitant to trust the task to
someone unfamiliar with the requirements. Accordingly, the more
rational approach is to match the sizes of the components.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.



In the "old days" my friend, Bicycle Bob, put a 26.4 Cinelli bar
through a 25.4 SR road stem by prying the clamp apart a little. He rode
it many hard miles without a problem. Your mileage may vary.

Dano
Lopez Island WA

"Ed" wrote in message
...
In article , Steve Sr. says...

Is this small diameter difference likely to cause a problem in real
life? I am trying to put a high angle (130 degree) stem on my road
bike to improve the fit and the high angle stems seem to only
available for Mountain bars.

Thanks,

Steve
I did this for the same reason. If the stem does not have a removable
face
plate the bends in the road bar will not fit through the hole in the stem.
Get
a one inch ******* (half round) file and enlarge the hole. The radius of
the
file and the radius of the hole match closely so it is easy to enlarge the
hole
evenly. Check you work by trying to put the bar into position in the
stem. If
the stem head is aluminum you should be done in 15 minutes. Steel may
take much
longer.

I was amazed that the 0.6mm difference in diameter is enough to prevent
the
bends in the road bar from passing through the hole in the stem.


0.6 mm is huge in this kind of work. Try to fit a bearing in a hole that is
0.6 mm to small. Boy, that would be a press fitting,

Lou

In article , Lou Holtman says...


"Ed" wrote in message
...
In article , Steve Sr. says...

Is this small diameter difference likely to cause a problem in real
life? I am trying to put a high angle (130 degree) stem on my road
bike to improve the fit and the high angle stems seem to only
available for Mountain bars.

Thanks,

Steve
I did this for the same reason. If the stem does not have a removable
face
plate the bends in the road bar will not fit through the hole in the stem.
Get
a one inch ******* (half round) file and enlarge the hole. The radius of
the
file and the radius of the hole match closely so it is easy to enlarge the
hole
evenly. Check you work by trying to put the bar into position in the
stem. If
the stem head is aluminum you should be done in 15 minutes. Steel may
take much
longer.

I was amazed that the 0.6mm difference in diameter is enough to prevent
the
bends in the road bar from passing through the hole in the stem.


0.6 mm is huge in this kind of work. Try to fit a bearing in a hole that is
0.6 mm to small. Boy, that would be a press fitting,

Lou


True. But the part of the handlebar where the bends are is less than 25.4mm.
The bends will not fit through 25.4 hole but will fit through a 26mm hole.