I use it on my mountain bike over some fairly rough terrain - not jumps and mountains but trails and gravel roads and it holds well. My handlebars widen at one point so the clamp sometimes slips towards the narrower end of the handlebars but I can readjust it easily and it's good for hours at a time. The lock is very hard to flip the switch on and I can never remember which way to slide it to lock it as there is no indicator where you can see it. But it works and the price is right!