stem shim question
 

If you have a handlebar with a 25.4 diameter mount, do you get a stem with a 25.4 clamp, or do you use a stem with a 26.0 clamp with a shim?

How well do shims work on handlebars? Do they slip or stay pretty stable?

For me, the stem is dependent on the top tube and handlebar in order to achieve the desired fit. If the handlebar happens to have a 25.4mm clamp section I'd prefer to have a stem with a 25.4mm clamp, but if I don't easily find one I have no qualms using a shim. The brand (group), angle and finish are all things I consider. I have used both the Nitto and VO shims and they work as advertised and are plenty stable. You do need to take care when installing them not to scratch the engraving on your fancy handlebar, though.

A stem with a 25.4 clamp is preferred for 25.4 handlebars. I am using a Nitto Technomic quill stem (26.0 clamp) with my 1988 Fuji Pulsar's original handlebars (25.4). My shim is home-made from an empty solvent can (steel material). No slippage using the shim. Some use aluminum material from an empty pop can, but my choice is steel over aluminum. Whatever you choose, I see no reason to spend around $10 retail for a shim.

Nah. Ten bucks is ridiculous. I made mine out of brass shim stock. Works great.

I'll be the voice of dissent. Properly sized, finished and shaped shims are worth $10 to me.

That's a good point Colonel. I'm forgetting the OP might not have the tools and facilities, or materials, to properly size and finish a shim.

I recently had to deal with a 25.4mm bar too when I was building up a project bike with a 1990's ITM stem that had a clamshell hinged type handlebar clamp. I was really surpised to find out that the stem required a 25.4mm bar when I could not get the Mavic 350 26mm bar to fit in it's hinged clamp. Do most ITM stems require a 25.4 bar?? I thought they were mostly 26mm clamps on them. If that is the case, switching over to an ITM stem might also be a good solution, instead of shimming your bar.

Chombi

I agree. I the stem is the right fit, and you can't find the same thing in 25.4 got a shim. But spend the money for one don't just use a few old beer cans.

Sounds like reasonable advice to me. I think I'll just find a stem with a 25.4 clamp. Thanks, everyone.