Seat Post Slipping

[BigTone0777]

Hi, I have noticed that my seat post is slipping to the point that I have to heighten my seat after a few rides. When I bought the bike second hand they guy I bought it from had managed to strip the threads in the collar so I'm guessing he had the same problem. I'm not exactly a lightweight at over 16 stone but I'm sure this shouldn't happen as regular as it is. Id there anything I can do to remedy this?

 

[betty swollocks]

Replacement collar
Seatpost shim

 

[accountantpete]

There are various possible solutions - new seatpost, better clamp, or you can get a friction enhancer which is made for carbon products to save them from overtightening - see here for example

 

[BigTone0777]

Thanks for the replies, I'm wondering if it's a cheap misfitting seatpost as it moves extremely freely once I've released the clamp which I've already replaced

 

[screenman]

Can you or somebody else like the LBS measure it, I have seen 27mm post in a 27.2 tube and I also saw a Halfrauds guy hammering an oversized tube into a new bike once while the customer was waiting to pick it up.

 

[accountantpete]

Thanks for the replies, I'm wondering if it's a cheap misfitting seatpost as it moves extremely freely once I've released the clamp which I've already replaced

It shouldn't do that - the fit should be snug. I'd measure the seat post diameter accurately with a pair of calipers/adjustable spanners etc and then determine what size you need.

 

[Angelfishsolo]

Holy unlyrical lyrics rap man

Can you or somebody else like the LBS measure it, I have seen 27mm post in a 27.2 tube and I also saw a Halfrauds guy hammering an oversized tube into a new bike once while the customer was waiting to pick it up.

 

[BigTone0777]

It shouldn't do that - the fit should be snug. I'd measure the seat post diameter accurately with a pair of calipers/adjustable spanners etc and then determine what size you need.

Looks like a trip to the LBS as I haven't got anything accurate enough to measure .2 of a mm.

I don't have the greatest of confidence with it coming from Halfords when new!

 

[accountantpete]

You can always make a shim with a tin can - cut out a piece and wrap it around the existing seat post.

 

[BigTone0777]

I don't think it's out that much to actually fit anything in to shim it, it just moves very freely when loosened. I'll have a better look at it tonight and see if I can fit a feeler guage between the post and seat tube

 

[HelenD123]

Some of the friction enhancer stuff fixed my slipping seatpost. It already had a shim in and the next size up seatpost was too big.

 

[BigTone0777]

Well, I've just loosened my seatpost and removed the slippy shoot someone had put on it and the seatpost rocks in the seat tube even with the post most of the way in. Looks like a trip to my LBS to get them to try a different post in and get my wallet out!

 

[smokeysmoo]

Well, I've just loosened my seatpost and removed the slippy shoot someone had put on it and the seatpost rocks in the seat tube even with the post most of the way in. Looks like a trip to my LBS to get them to try a different post in and get my wallet out!

Definately got the wrong size post in it, even if the LBS can't measure it to 0.2mm, they'll have a selection of posts they can try. They'll know within the first few mm's which is right.

Good luck, I'm sure it will be sorted once you visit your LBS

 

[BigTone0777]

Definately got the wrong size post in it, even if the LBS can't measure it to 0.2mm, they'll have a selection of posts they can try. They'll know within the first few mm's which is right.

Good luck, I'm sure it will be sorted once you visit your LBS

That's what I was thinking, they could try some post's in and I'll buy the one that fits snug!

 

[e-rider]

sounds like the post diameter is too small - this could be for 3 reasons:


1. crap seatpost

2. wrong size seatpost

3. cheap frame bored out too much



I've had trouble in the past with correct size seatposts slipping - it was due to 2 things:



1. being fat

2. crap seatpost clamp



Didn't lose weight but did change the clamp - problem solved!

Buy a good quality chunky clamp with a large steel bolt