brian3069

I have a Cinelli quill stem with a 26.4 clamp. The previous owner mounted it to a set of 26.0 handlebars. Will this be safe to use, or do I have a nice paper weight.

Mad Honk 

Brian,
If you are talking about the handlebar clamp it is only compressed about 1/16" inch over the circumference of the clamp and should not be anything to worry about breaking if you move back to the correct bar size. If it is the stem that has been shaved down to fit an undersized steerer tube then yes, it is a paperweight. HTH, MH

Crankycrank

Probably nothing to worry about but I would get a .2mm shim for the bars just to ease my mind.

jideta

I seem to remember seeing stems with stress cracks from using smaller bars.
A half a mm may not seem like much but apparently over time it makes a difference.
Cinelli makes a couple of different stem types that tighten differently also and I don't remember what type I saw the cracks. Some even have a colored shim/spacer that may or may not help.
I run Giro d'Italia bars (Cinelli) and if I remember correctly they come in two widths: 26.0 and 26.4 the latter being I believe proprietary to Cinelli.
When I was swapping out Cinelli stems and different bars I tried to make sure they always matched.
YMMV

brian3069

It's a very nice 1A from the early 80's. If it were to be used I'd find the proper sized handlebars, but think it will go on a shelf for now.

Thanks for the replies.

bikemig 

I have a bike I picked up with a 3T stem and cinelli bars, sort of the opposite of your problem. I'd like to use that stem but maybe it's better to be safe than sorry. When fixing up old bikes, I tend to run new stem and bars on bikes I ride a lot. What the heck, that is not a place you want a failure.

jideta

Finding the right Cinelli stem was pretty frustrating. Once you found one in good condition, it would be the wrong size! Finally I just got two bars, one 26.0 the other 26.4 since you gotta take everything off anyways. I think I paid like a hunski for a NOS Giro bar, right before Cinelli decides to reissue it and sell it for $40!
I think I went from stem length 100mm to 70mm and all the sizes in-between before settling on an 85 (which now feels small).
It's one those things that feels good to get right:

Eric S.

On Sheldon's site, he talks about the (odd) size of 25.8mm, saying that it was intended to be used with 25.8mm, 26.0mm and 25.4mm stems. That tells me that .4mm is not really worth worrying about.