Originally Posted by
FBinNY
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...