I am using bullhorn handlebars and do standing sprints away from traffic lights, so it's conceivable that I'm putting more force than was intended to be handled by the design. I have less than 1500 miles on my handlepost in the current configuration, and only about 500 miles on it before with a flat handlebar. I did saw about an inch off both ends of the handlepost to make it shorter (bottom of the inner, top of the outer), but I'm confident that this particular modification is not a direct cause of the wear.


well..... ??
That seems to be a different post than I am used to... does the picture show some kind of shim ? or is that the part you cut off ? The clamp is at a strategic position and if you cut the top off, it might not work as intended....

The above copied sentence from you..
Standing sprints with a bullhorn bar... did that Bullhorn bar came standard ? As far as I know all Bullhorn bar equipped bikes have T - onepiece tops and are not adjustable in height ... well a little with the syntace double clamps... I am sure that is the reason for your handlebar turning ...

The slot and the knob are there that the handlebar if it is loosened not turn all over the place, and to guide it somewhat in a general correct position when you close it again, after it has been folded, but not to keep the handlebar from rotating when the quick release is closed properly.

You should invest in a Jetstream one piece stem. that will get you down in front, and will eliminate the rotating all together. And I do have them back in stock as well.


http://www.thorusa.com/images/dahon/...es/jetstem.jpg

Best Thor