Ok I will hammer punch them to be safe and make me feel better too also I swear there a bit to left so I can realign at same time.

 

I have 12" non knurled apes on mine and there's been 2 occasions that hard bumps made them roll down toward me and the clamps were still so tight I had to loosen them up to readjust. Jester's tip is a good 1. I just used a small grinding wheel on a Dremel and made a diagonal cross hatch pattern on mine's clamp area and no issues since.

I know a couple of guys who had the same issue and what they did was drill holes in the bottom of the bars in the clamp area and put ball bearings that were slightly bigger on the hole and clamped em down and they won't budge.

 

I don't know if I'd be happy with this. The grinder won't raise the metal like knurling or punching, you're just removing material. But, if it works then that's all the matters.

 

Follow Jester 08 advice,and be done with it.

 

I think what "another_victim" said might be the cure. It's bad enough having the feeling that they'll move even though they might not. I had 10" Z bars, no knurls, on before and I had that feeling myself. It didn't feel 100%. Now I've got knurled 14" Road 6 Customs apes on and they're tight as hell. So try some home cooked knurling...

 

Take a strip of 1 inch wide emery cloth. And wrap only once with no over lap. Position where you want then before completly torqued down. Carborundum emery cloth will work the best.

 

I wouldn't ride without knurling. Usually clamps are aluminum and bars are steel. Being that steel is harder I would use a punch to dimple the bars. Don't over tighten your clamp screws or your going to strip out the threads on the aluminum clamp.

 

By bars would move if I hit a big bump, or had to pull on them when getting ready to go over a hole that I saw at the last minute. I finaly put a quarter size star washer (after prebending it), I put it under the bars. I tightened them down in stages alowing time for it to form. Them haven't moved sense.

 

Just out tinkering on bike and pushed so hard on bars I nearly popped a hernia! Couldn't get them to move just front forks dunk down!
Will still use the hammer and puch method I think.

 

You can also use some corse grit sand paper wrapped around the bars for traction.
I rode with 16" non knurled apes for a while and they still moved no matter what i did. I got rid of those and only ride with knurled bars now. Not worth the chance of those bars coming down while doing 50mph and hitting a pothole (happened to me once and it sucked ***).