has anyone ever clamped a 26mm drop bar with a 25.4mm stem? the 26 seems like a rare find, i hate that i have it. stems with 1" clamps are so much easier to find. i can see danger in clamping a thin bar with a fat stem, but the other way around seems doable. am i asking for trouble?

it won't work.

26mm stems should be fairly easy to find, so you might not be looking in the right places.

Less than $50 bucks for the right stem is cheaper than a trip to the hospital. So why ask for trouble?

Your bike shop should be able to order from the Quality Bike Parts catalog, which will have 26mm stems in various rises and lengths made by Dimension or Profile. Here's a sampling from Harris Cyclery

I've tried this once, but will not again. It doesn't seem like that much of a difference between 25.4 & 26.0, but trying to pry a 25.4 stem open enough to accept a 26.0 bar will work, but generally damage to the stem in the form of gouges to the soft metal in the process is the result. My conclusion is to get a 26.0 stem for a 26.0 bar.

A set of shims, is how a smaller bar fits in a lager 26mm stem,
there are shims down from oversize type stems, now, as well
To both, 1" and 26mm ..

the shims would solve my problem, and i'll have a look at that harris site, too. thanks for all the replies!

I may be confused, but if I read the OP correctly, the bar is 26.0 and the stem is 25.4. Which is to say that the stem is made to take a thinner bar than you have. If this is true, then adding a shim won't help; it will make things worse. If the situation were reversed -- i.e. you were trying to fit a 25.4 bar into a 26.0 stem -- then the shim would solve your problem.

^^^^This

Dimension makes a stem that your looking for.

+1, the stem , being smaller in diameter, than the bar, that the Poster
wishes to fit , that 0.6mm is huge, in machine terms, a No-Go fit.
Get the right stem.
you can get one of the new oversize stems, and future-proof, the bar choice.

Eccolo.
0.2mm diameter smaller would work and there are 25.8mm clamp stems for this reason, but with 0.6mm smaller clamp diameter it just won't work. It might break the clamp, you might get it on but not be able to get the screw to engage, you might get it on but the deformation in the clamp would be so extreme that it wouldn't have a purchase on the bars, or you might deform the bar at the clamping location ... which I'm sure you can see would be dangerous.

You're not asking for trouble, you're asking for the impossible.

You can shim a small bar for a larger stem, but you can't shim a large bar smaller. So it's strictly a no-go. If you have the resources most 1" stems can safely be reamed out to 26.0mm but be sure you know how to do it, and stay on size.

If you're having problems finding 26.0 stems, I have a decent assortment from Thomson and Oval Concepts stems in stock, so if that's of interest you can PM me what you need, and I'll give you the choices.

How is a 26.0 stem hard to find?

I could go to my LBS and find stockpiles of them.

the websites i normally use stock 25.4 and 31.8. there are precious few 26mm, none with the length or rise i need. i've had eight bikes, which is a small sample size compared to some of you guys, but only one handlebar has been 26mm. between that and my fruitless searches, i figured i was hosed. i dunno, maybe they are mtn bike websites. anyway, i've found what i need at harris cyclery (thanks, tmat!), but FB i'll PM you.

@ strock, you're right, i read it as him advising me to shim down an OS stem.

26mm is a normal road bar, but may be superseded,
(after Cinelli, rounded off their 0.4mm, that made their stem/bar-set mutually exclusive)
quill stems for classic road bikes, used this standard ..

threadless seems to be convening around oversize, threadless, now,
at the high performance/cost sector,
but the other types are still in the supply chain, for the Lumpen masses.


Dude! , there are real bike shops , Even in Memphis , get out more.

Agreed. 26.0mm stems and handlebars were the old road "standard". Back in my day they were as common as dirt. Local used-bike-parts emporiums have zillions of them.

Shimming down a 31.8mm stem would be the way I'd go if a 26.0mm stem was not readily available. I would never use the 25.4mm stem for those bars.

FB, the stem arrived today, that was a quick delivery. i wish i had time to install it and take a test drive tonite! thanks for the help.