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seatpost slippage

Old 07-25-14, 11:11 AM
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seatpost slippage

So I'm having an issue with seatpost slippage, the bolt seems tight enough and I've cleaned and regreased, but it goes down a few cm during a ride. kind of annoying, as I think it does mess with my technique a bit. Although I have the right size post for the opening, should I try some sort of shim or a specific type of grease?
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Old 07-25-14, 11:14 AM
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Try some carbon assembly paste- has some abrasive in it. Also, try a torque wrench to make sure that you are tightening the binder bolt properly.
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Old 07-25-14, 11:23 AM
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thanks, yeah, I've been meaning to pick up one of those wrenches for myself. I'll look for the carbon paste around my local shops here
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Old 07-25-14, 12:44 PM
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Make sure that the clamp (or clamping ears if integral to the seat tube) does not close fully when you tighten the bolt. If it closes up you are just clamping it against itself. This would happen if an undersized post is fitted, for example, or if the ears have been distorted from previous abuse.
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Old 07-25-14, 01:17 PM
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Measure the seatpost to make sure it is not undersized. I have had some 31.6 mm posts that were actually 31.45 mm and would constantly slip. Also if the post is the correct size carbon paste helps.
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Old 07-25-14, 02:17 PM
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Every thing was right & still slipped, so I added clamp on band directly around the seat post itself .. It sits atop the frame and its band clamp.

on My Brompton It is another QR. that i took the Lip off of so it slides over the 31.8 post... to fold the bike I open both levers.


Undersize post like above, I'd just get another one that was right.


Ive used an adjustable reamer and shaved seat tube ID till the next larger +0.2mm, post just slipped in . for a perfect fit.

Last edited by fietsbob; 07-25-14 at 02:20 PM.
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Old 07-25-14, 02:24 PM
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I had that issue with my previous bike (which had the original seatpost), so I finally took out the seatpost and using a file made several "abrasions" on the post. I also did the same, but to a lesser degree, inside the seat tube. This then allowed for more gripping surface -never had the problem again.

Best regards
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