Bicycle Mechanics - Hoping this is a real simple question? -Handlebar shims..?

I replaced the bar on my Trek 7.0. However the new aluminum bar is a bit narrower, and some older Performance extension-bar add-ons I have will no longer clamp down tight on this bar! The bar measures about 2.1mm dia, but so do the extension clamps, giving me no room to tighten them! :notamused:

So, does anyone know where I can get two handlebar shims (about 1" wide ea) to increase the bar's fatness? Tape wouldn't be strong enough, I need something in metal or very tough plastic I think.

Thanks..

2.1cm or mm? I assume cm, but I'm still a bit confused.

Standard mtn handlebars are 7/8" (22.2mm) in diameter at the working ends, regardless of material. All grips and bar ends are sized for that, otherwise we'd all go nuts dealing with compatibility in grips, bar ends, and whatnot. Check your measurement again. It's also possible that your end wont clamp tight because you have a thin walled bar, which needs an internal support to keep it from shrinking a bit when clamped.

Aluminum beer/soda can, cut into shims.
Careful, the edges are sharp.

Aluminum beer/soda can, cut into shims.
Careful, the edges are sharp.

+1 ... beer can aluminum can be cut with sharp scissors.

2.1cm or mm? I assume cm, but I'm still a bit confused.

Standard mtn handlebars are 7/8" (22.2mm) in diameter at the working ends, regardless of material. All grips and bar ends are sized for that, otherwise we'd all go nuts dealing with compatibility in grips, bar ends, and whatnot. Check your measurement again. It's also possible that your end wont clamp tight because you have a thin walled bar, which needs an internal support to keep it from shrinking a bit when clamped.

Ahhh, but I don't have standard mtn bike bars... I had the flatter bars on my Trek hybrid replaced with some moderately curved pullbacks. This new pullback bar was a spare part for a shaft drive automatic hub bike; it's dull silver-colored aluminum and it's definitely smaller in dia than the previous stock bar was!

And I'm not talking about bar end extensions here either, I'm talking about curved, forward riser extensions, that have opening clamps so they can be screwed down together around any section of the handlebar. These extensions fit okay on several of my previous stock and chromed bars, but on my new aluminum ones they will not tighten down far enough to hold, because the bar is thinner!

I don't think beer or soda can aluminum will work here either... One thickness of it would be too thin; I'd need possibly 3 or 4 thicknesses, and so the possibilities of it sliding around and not holding are fairly good...

162668 How about this? JB Weld and aluminum shim .You might find a shim at a LBS or hardware store. Jack

When you say "...because the bar is thinner!", do you mean it is smaller in diameter, or the walls of the tubing are thinner (as FBinNY suggested)? If they are smaller in diameter, then you could come up with something for a shim. If, however, the walls of the tubing are thinner, then the strengthener that FBinNY suggested might be the only way to make them work. If you are trying to mount in an area that is inaccessable for a strengthener, you may be in for more trouble than these bars are worth. Only you can decide how much trouble is TO MUCH trouble.

Okay, found the problem... It wasn't with the bars but with the one of the extension clamps. Evidently it had stretched open a bit because of repeated tightening..? I put a piece of plumber's pipe wrap inside the clamp, and now it wraps around the bar firmly enough!

Thanks for all the suggestions guys, ">**)