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Question for Anvil(2 posts)

Question for AnvilAaronL
Mar 14, 2002 11:36 AM

I hope you can help me on this.

My seatpost is slipping and I'm not sure if I can can fix it.

First, I have a carbon post, 27.2 that was used on my previous bike, it never slipped before.

Second, the seat tube was checked by the shop and it's is 27.3, supposed to be 27.2.

I bought a Salsa liplock collar since it's supposed to have the most force and surface area.

I cleaned the seatube and there is no grease on the post.

Will .1 mm make a differnce? I've checked to make sure the collar is not touching the post or that the gap in the seat tube is not touching when it's clamped down.

Luckily the frame rep (Fort) is good and will get me a new frame. But I would like to keep this one, if at all possible.

Any tips, or is .1 mm going to haunt me? I was thinking of getting a Ritchey WCS post since the surface on it is a bit rougher, maybe give a bit more bite.

Thanks in advance.
re: Question for AnvilAnvil
Mar 14, 2002 3:16 PM
The problem you have is one of clamping pressure. Carbon and Ti posts are both known to slip in steel bikes, usually because they tend to have flexible walls and polished surfaces which is hard for a steel tube to grip well, especially if the seat tube has been honed (which smooths the ID of the seat tube and minimized marking/scratching seatposts). If you want to keep using your carbon post, lightly rough up the ID of your seattube with some 120 grit sandpaper. Don't go crazy, just rough up the ID with the paper as far as your finger will go. You can also flip the clamp around so that it is opposite the slit in the seattube. There's other things to do, but that's a start. Send me a note off list and let me know how it goes.