Slipping seatpost

[rpm]

So I got a new alloy Fizik Cyrano seatpost to replace the old beat-up ITM on my steel Serotta. Unfortunately it slips. It's nominally 27.2 but it went in a bit easier than the old one, and it sinks. It also creaked like crazy but I think I've settled that down with generous applications of lube.

Would carbon paste help, or should I just give up on it and find another post?

[oldpotatoe]

So I got a new alloy Fizik Cyrano seatpost to replace the old beat-up ITM on my steel Serotta. Unfortunately it slips. It's nominally 27.2 but it went in a bit easier than the old one, and it sinks. It also creaked like crazy but I think I've settled that down with generous applications of lube.

Would carbon paste help, or should I just give up on it and find another post?

Wouldn't hurt.
If it's alloy, knurl it..good bike shop has a knurling tool.

[tttsmm]

the alloy 27.2 seems to be slightly undersized, i had the same issue with mine & ended up selling it :p

[rpm]

the alloy 27.2 seems to be slightly undersized, i had the same issue with mine & ended up selling it :p

Hmm. What did you buy in its place?

[rpm]

Wouldn't hurt.
If it's alloy, knurl it..good bike shop has a knurling tool.

Thanks, OP. I'll ask my LBS.

[shovelhd]

Use a torque wrench on the clamp.

[mvrider]

Beer can shim?

[saab2000]

Paste and plenty of it.

[buddybikes]

You could break the seat binder or even bend the tube, just get a right sized seatpost since you know it is not your frame.

If the new post is that important to you, yes a very thin shim of some sort. Another option for last resort is a hose clamp on seatpost where it touches the frame. Had this for years on an old mtn bike, finally got smart and bought the right size seatpost.

[rpm]

I think I'm going to bite the bullet and get another seatpost. Fortunately I bought the Fizik on sale. i like an alloy two-bolt post with a healthy amount of setback--maybe the 3T Doric or a Paul Tall and Handsome. Anybody have feedback on how these fit? I don't want to repeat the problem again.

[ultraman6970]

If its the right size, just a lot of carbon paste.

Measure the seatpost with a good caliper, some manufacturers just have tolerances like c r a p.

[tch]

... you can wrap the post with something like electician's tape and then tighten up on that. I've done this w/lots of things, both on & off bike, and it's a decent solution if the issue is pretty small.

[bfd]

If its the right size, just a lot of carbon paste.

Measure the seatpost with a good caliper, some manufacturers just have tolerances like c r a p.

Actually, you should take it to a shop and have them measure the seat tube inner diameter. A good shop should have some of the tools you'll need:

1. a seat post sizing rod like this one to get the exact size you need:

http://www.universalcycles.com/shopping/product_details.php?id=40887

2. If the seat tube is too big, you need to knurl your seatpost, a good shop can do it with this tool:

http://www.universalcycles.com/shopping/product_details.php?id=27923

3. If the seat tube is too small, you can ream it out to fit the next larger size using something like this tool:

http://www.universalcycles.com/shopping/product_details.php?id=40359&category=4162

These are specialty tools that most good shops will have and should know how to use! :eek::banana::butt::confused:

[Tony T]

Make sure that the clamp bolt is staying put. I had this problem (same seat post, btw), torqued to 5nm, then after a few rides, I re-torqued and it was the clamp bolt that was loosening. Loctite on the clamp bolt fixed my problem.

[David Kirk]

You've gotten plenty of advice here so mine might not be value added but what the heck -

The Fizik alloy posts have a very hard and slippery anodized finish and this, combined with a no-doubt very smooth inner seat tube will make it tough to get things to bite. So.............

I'd put the post in the frame and using a piece of tape mark the post's height so that you know everything below the tape line will be buried in the frame. Take it out and using some 80 grit sandpaper scuff up the post were it will not show once it is in the frame. Do not bother doing it all the way to the bottom of the post as there is no clamping load there anyway. You don't need to go crazy with the sanding - just get rid of the shine in the area to be clamped.

Now clean the post well and remove all the grease. Next clean the inside of the seat tube of all grease. I like to use a wooden dowel and a rag with some simple green on it.

Once everything is clean and dry put carbon paste on both the post and on the inside of the frame.

Remove the frame's pinch bolt and make sure it is straight and well greased and then put the bolt back, place the post in the frame and tighten it down and you should be good to go.

Now - ride like the wind!!

dave

[PaulE]

My CSI had the same issue with a Thompson seat post slipping and to a lesser extent with a Nitto post. I didn't sand any of my post or use any degreaser inside my seat tube, just a rag, but carbon paste did the trick for me and the post no longer slips.

[rpm]

When DK speaks, I listen. I'll try the sandpaper and paste before I write off the post. Thanks!

[rpm]

Follow-up: I tried roughing the seatpost and using carbon paste, but the Fizik still slipped. So I got a Paul's Tall and Handsome post. Problems solved. No slip, no creak. Easy micro tilt adjustment. A tad heavy, but a very well-designed and well-made post.