Old 11-06-13 | 09:01 PM
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5b00
Senior Member
 
Joined: Sep 2008
Posts: 68
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From: Maryland
Unwanted rotation in Dahon adjustable handlepost

Does anyone else have excessive play in Dahon adjustable handleposts? I'm aware that this was brought up in 2008, but I'd like to see whether current designs have solved the problem or whether I should give up and get a fixed handlepost.

Dahon - A potential SAFETY ISSUE

My handlepost rotates around the steering axis with just a light touch, even with the quick-release tightened as tight as I can get it (ludicrously so). I measured the play to be about 13 degrees, which means that it moves by more than an inch at the end of the handlebars. The play has gotten so bad that the steering is extremely imprecise: in leaning turns there's always a scary moment where the handlebar and the wheels decide that they want to go in opposite directions. I've almost bitten it trying to balance when nearly-stopped.

I'm pretty sure that the play results from wear on the inner and outer pieces of the handlepost, especially wear on the anti-rotation dimple. Here are some pictures:

This shows the pattern of wear around the dimple. Sorry for the weird shadows.


This shows some galling on the inner part, which may not be a direct cause of the play but gives some perspective on how tight the clamp has been. The wear also suggests that the clamping force is unevenly distributed. It also creaks like crazy unless I ride no hands. I am closely monitoring this area for cracks. The parts in the shadow are worn from rubbing against the dimple.


You can see that the inner part is damaged by resting on the bolts holding the clamping mechanism in place on the outer part. For a while, this was a good thing because it held my handlepost in a consistent position. Now the two indentations are wallowed out and also contributing to the creakiness.


Looking down into the outer part. The two circles in the middle are the bolts that bump against the inner part.


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.

Any other reports? Advice?
Attached Images
File Type: jpg
inner handlepost 1.jpg (35.2 KB, 59 views)
File Type: jpg
inner handlepost 2.jpg (38.8 KB, 50 views)
File Type: jpg
outer handlepost 1.jpg (30.8 KB, 58 views)
File Type: jpg
outer handlepost 2.jpg (34.4 KB, 48 views)
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