My seatpost slips no matter how hard I try, After a few miles I have to stop and raise the seatpost at least 5-10 mm and it's pretty annoying. I've tried tightening the Turtleneck clamp as much as I can but to no avail It's seems like the clamp isn't strong enough. I've cleaned the shim and the seatpost but it doesn't do the trick... The seatpost and the shim are new by the way. I am trying to get to the point that it doesn't slip and you don't need to break a finger when tightening the clamp.
This problem was cured on my bike by greasing the contact area between shim and frame.
I have tried to put some lube between the frame and the shim.... Still doesn't work.
I have tried to replace the Turtleneck clamp and the shim but the seatpost still sinks.
I am loosing patience here, this is really bad since I weigh less than 120 lbs and I cannot understand what is wrong with the bike.
I am not riding hard at all, I ride mostly on the road and sidewalk, not even bike paths !
When I bought the bikes last month I was quite happy but since then I am having all kind of issues with both bikes. Overall I have spent more than 30 hours in total trying to solve this issue, I think I had enough.
When you tighten the clamp, does a gap remain in the slots of the shim, of the frame and of the clamp? If any of these close up, this would explain why you have a problem.
I am sorry but i am not sure i follow.... But if I did get it right, I do see a gap in the slot of the shim and of the frame.
The most ridiculous thing is the fact the I have received replacement parts from Dahon and they all act funny, the two clamps I got don't act the same, one feels much stronger and the other one is loose - even when removing the bolt, the 2 shims are different. but the bottom line is that I can tighten the clamp and the seatpost will feel very solid, I can't even twist it using some force, but when I ride less than a mile it will sink 5-10mm on me.