Re: Simple and easy bike handlebar mounts! (Image intensive.)
Surprisingly, I haven't found much of a difference with or without rubber shims. They tighten down pretty well on their own. I haven't had them move at all after going over rough terrain... But if you're using a particularly long or heavy light I'd imagine that they might loosen up a little. Though while riding tonight I did realize that they could be dipped in some of that liquid rubber grip coating for tools. That might be even better than rubber shims!
wasBlinded: Hm... Well, I've earned enough lumps on a bike that I'm not too worried at this point. Of course, one could always just flip them over so the light is beneath the handlebars. Or, now that I think about it, one could just take off the top hanger and wrap an elastic velcro strap around the light. I like the adjustability and solidity of my setup, though.