Alright so I do alot of ledges and stuff like that. Most of them are about 3-4 feet high. Every time I land (I land the right way both tires on the ground) the bars sometimes go foward. I always have to go home loosen the headsets bolts. Put the bars back into place. And retighten the bolts (yes I`am adjusting them all evenly). I don`t think the bars are stripped. Can someone please help me?

Take the bars all the way off, clean out the metal shavings from the stem and clamp area of the bars. Whenever they slip it shaves metal off, and it gets stuck in there and makes the bars slip even if they are tight.

Thanks man is it gonna be like engraved to the metal the shavings. Or will it just come off with a little fileing.

Don't use a file, just clean it out with a cloth. It's no gurentee that your bars wont slip, you probably need a better stem. Carry an alan wrench for you bars with you when you ride, it's small so that shouldn't be a big deal. Also when you tighten your bars up, use the hole in the back of a wrench for torque, you will be able to get your bars way tighter. I don't really know how to explain it, but you should be able to figure it out if you don't already know.

basically, as fuzzyryder says, use something for leverage when you tighten your STEM (not headset by the way)

also, notice where the bars tend to end up after you ride a bit and yank on them and what-not. This is the position you should set them at. I tried setting my bars pitched a little forward because I'm old school and that's how we used to set them in the 80's. But no matter how tight I cranked them, they always ended up parallel with the forks or back slightly. So I gave up on the Stu Thompsen bar-forward look, and they havent slipped since.

An old seatpost works to give you leverage on your stem bolts.


And if you have done everything from cleaing it out, to tightening it and it still slips, look into a new stem...

or stop riding off ledges...

or stop riding off ledges...leave that to mountainbikers