Seat post slipping

[sup4012]

I have noticed that my seatpost has been slipping. I contacted Trek and my local bike shop for details. Two replies: (1) seat post is not the correct post diameter (2) seat post clamp is not tight enough.

My worry on the easiest solution is if I tighten the seat post clamp I may crack the carbon frame. Trek would not admit the proper tourque which confussed me. I have spoke with the local bike shop (not a trek dealer due to personal choice) and they could only give me a range. My manual as I could see did not spec this.

Can anyone help me with the tourque spec before I have to go to the distasteful trek dealer!

 

[friedmikey]

I've been researching this issue, because my seatpost on my TCR has been slipping as well. It seems to be a fairly common problem when using a carbon frame and post. I'm also afraid of over-torquing. Here's some tips I've discovered or seen so far that may or may not help:

Clean every trace of grease off of the post and/or inside of the frame.
Very lightly scuff the seat post with sandpaper to remove the glossy surface.
Use some cheap hairspray (like Aqua Net) on the seat post. Let it set overnight.
Turn your seat post clamp around, so that the bolt is towards the front of the bike.
Use the Campagnolo Asymmetrical Seat Post Clamp. I'm picking mine up Thursday. Hopefully it works!

 

[JohnO]

Might want to check your diameters to be sure they are correct, and look for any form of lubricant on the seatpost or inside the frame.

I have a Trek carbon frame (Foil) and Campy carbon seatpost. Never had a problem with the seatpost being loose. I didn't need a torque wrench, just the hex wrench, snug it down firmly but not super tight, and it holds just fine. If the diameters are correct, you shouldn't have a problem.

 

[sup4012]

Go the info, thanks. I will try the solutions.

 

[friedmikey]

FYI, the Campagnolo seat post clamp I just got indicates to torque it to 7.4 lb-ft. I have no idea if that's the proper torque for your frame and post.

 

[Cheesy]

Scuff the surfaces in contact up a bit. I don't really have any experience with carbon bike bits, but when I used to put together the occasional carbon kayak paddle, I had to scuff & put some cuts in the contact surfaces when glueing the blade onto the shaft, otherwise the blade would move under force.