This is my setup. The bullhorn handlebars have a 25.4 mm stem clamp section and I had to relocate the grip shifter to a computer mount accessory bar.


The "shim" that you see is actually the top edge of the outer piece. It's bright at the top because that's where I sawed through. The clamp is still sort of in its original position with the screw attaching it to the dimple, but it's now closer to the handlebar by about an inch. I've read many of the posts about moving the clamp, and I don't understand the vague claims about there being an effect on the torsional rigidity. Are you saying that it's because I've removed some of the clamping surface above the clamp and that if it were still there, the post wouldn't be worn and twisting this much?

I'm aware that I fall outside of Dahon's intended use case and that my modifications really muddy the issue. But I still believe that the adjustable handlepost design is far from over-engineered and foolproof (maybe that makes me a fool). I just want to understand whether this is a typical failure mode and whether the solution is just to buy another post once the dimple is worn down.

Thanks for the comments, Thor. I'll probably be buying the Jetstream handlepost from you soon!