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26.0 handlebars in 25.8 stem?(13 posts)

26.0 handlebars in 25.8 stem?Bolivarroads
Jul 4, 2002 2:59 PM
My stem (3 TTT Forgie) is made for 25.8 mm handlebars. Can I use 26.0 mm handlebars with it?
You sure?Spoke Wrench
Jul 4, 2002 3:19 PM
I can't imagine a Forgie stem not being 26.0mm.

The other sizes that are common today are 25.4mm and 31.8mm. If you actually do have a 25.4mm stem, no way would I try to scrunch a brand new 26.0mm handlebar into it.
he's correctDrD
Jul 4, 2002 3:44 PM
Pretty much all of the non-oversized TTT product (bars and stems) are 25.8 - check out
Interesting.Spoke Wrench
Jul 4, 2002 4:03 PM
My QBP catalogue, which I use as a reference for everything, and which I've always to be reliable up to now, lists both 3ttt stems and bars as 26.0mm. Now I wonder how much other stuff in there isn't exactly right.
I don't know how it works,TJeanloz
Jul 5, 2002 4:30 AM
QBP lists almost all 25.8 stems as 26.0- enough that I think there's a measurement issue there somewhere (like the stem measures 25.8 completely closed, but when you have a gap, as you will, between the faceplate and the stem, it's 26.0). For example, Ritchey stems come in a bag marked "26.0" but have a sticker on the inside of the faceplate that says "25.8".
and he can use it with 26.0 bars. i do.colker
Jul 5, 2002 3:41 AM
i have deda bars(26) on quill itm stem(25.8). no problem.
no problem...C-40
Jul 5, 2002 7:40 AM
As long as the stem is an open-face type, 25.8 and 26.0 sizes can be used interchangeably.
Jul 5, 2002 9:29 AM
But, but, but don't you realize that's .7% error! Egads! It will NEVER work. At least it will NEVER work well with that kind of error. Anybody who has said that this works for them is CLEARLY wrong. The numbers prove it...

I couldn't resist...
wrong again...C-40
Jul 5, 2002 12:13 PM
The numbers prove that it WILL work if you do a thorough analysis.

The open face design reduces the error to a much smaller percentage, since the face plate is free to move. The area of potential interference is at the gap between the face plate and the stem extension, where there is no material to cause any interference.

Handlebars aren't that rigid either. They will easily conform to a slightly out of round configuration (they are rarely round to start with).

You can even use a 25.4 diameter MTB stem with road bars, IF you chamfer the edges of the face plate and extension to increase the effective gap between the face plate and stem to about 5.5mm.

Couldn't resist.
Jul 8, 2002 4:10 AM
Why are tolerences on handlebars so imperfect, and yet, so perfect on derailluers?

FWIW, I know that it's perfectly o.k. to run a 25.8 stem with a 26.0 stem- works just about as well as a Campy9 derailluer with a Shimano9 cassette...
ignorance is bliss....C-40
Jul 8, 2002 8:17 AM
Someone once said.

You could use a good lesson in geometry and trigonometry and some practical experience in manufacturing.

Measure some handlebars with a micrometer sometime. You might be surprised how much they are out of round and smaller or larger than their advertised size. The reason is simple. Handlebars don't need to be that perfect to function. The processes used to form aluminum tubing aren't that accurate and don't need to be, since the tubing can readily conform to a slightly out of round shape.

The comparison of shimano/campy cassettes to handlebars is ludicrous. The bar/stem error is less than 1%. Compare that to the 20-40% accumulative positioning error that can occur when cassettes and derailleurs are mismatched.
Yes it is, isn't it?TJeanloz
Jul 8, 2002 8:21 AM
I'll get some lessons in geometry and trigonometry and some practical experience in manufacturing if you'll spend 5 years working as a bicycle shop mechanic. You and I might both be surprised at how much we'd learn.

"Handlebars don't need to be that perfect to function" is your assertion, which I agree with.

My point, over the years, is that derailluers don't need to be (and aren't) perfect either.
Jul 5, 2002 1:03 PM
that was SOOOOO evil .... but SOOOOO funny.