My seat post keeps slipping into the frame as I ride (my seat keeps getting lower). This never used to happen and just started about a week ago. I have a CroMo frame with quick-release for the seat. I really want to leave the quick-release because I have a nice Selle Italia that attracts attention to my bike when I leave it on, and I leave it locked outside in downtown Toronto. Any suggestions?
And yes, I have tried tightening the quick release.
05 Specialized Rockhopper. mid 90's Gary Fisher Wahoo
i had an old bike with the same problem, once i use some dirt and soil to "lube" the seatpost, i know its not right to do that but stopped the problem for me, y have read that using grease for the seatpost instalation is the best way to go so might try that
My bike came with one of those quick release seat post clamps. It seams I could never get it tight enough to where the seat post didn't shrink into the frame of the bike. So, I installed a hose clamp over top of the seat post clamp as sort of a 'stop'. It's ugly, but it works.
I had the same problem with my post. I just went ahead and took tin snips and cut up a bunch of rectangular pieces from a coke can. I then wrapped one around the seatpost and tried to tighten, no luck so tried anther one and it tightened up perfectly.
I had the same problem on my bike, and the issue was easy to resolve once the mechanic at the LBS gave me advice. Because it sounds like yours used to be OK, but now started slipping, it could be your problem too.
If there is a shim, ensure that the slot in the shim lines up with the slot in the seat tube. Mine didn't, and once I twisted the shim the seat holds position quite well.