Seat sliding down

[PamNY]

The seatpost on my bike will not stay where I put it. I had a Pinhead security thingie put on it, and I assume that might be the problem. I've had people with stronger hands than mine tighten it, and it still slides down.

I'm going to check with the LBS that sold me the Pinhead, but wondered if there's anything else that might cause this problem. I weigh 110 pounds so I don't think I'm putting undue pressure on it.

[Blueberry]

The seatpost on my bike will not stay where I put it. I had a Pinhead security thingie put on it, and I assume that might be the problem. I've had people with stronger hands than mine tighten it, and it still slides down.

I'm going to check with the LBS that sold me the Pinhead, but wondered if there's anything else that might cause this problem. I weigh 110 pounds so I don't think I'm putting undue pressure on it.

What is your seatpost made out of? How about your frame? Sometimes seat tubes are slightly oversized and seatposts are slightly undersized. A bit of carbon based on the seatpost (where you would normally put grease) can help.

Did you have this problem at all before the new collar? If not, it's probably a clamp problem. Are you sure it's the right size?

I have had this problem on a bike - but a new collar, new seatpost, and by LBS tightening it seems to have resolved the problem.

Good Luck!!

[oxysback]

I had this problem with the seatpost on my commuter. Since it's made of aluminum, my LBS fitter guy used some fine sandpaper to roughen it up a bit, the he put some kind of gel stuff on it. Hasn't budged since!

Of course, this is a BIG no-no with a carbon seatpost. The fitter said sometimes the post is just too smooth and it happens no matter how little you weigh.

[Thorn]

I'm sure the previous postings are more logical, but in the spirit of Paris-Roubaix this weekend....two years ago, Garmin solved the problem with a trip to the hardware store...

http://velonews.competitor.com/2008/04/photos/insurance-against-seatpost-slippage_74584

Full article...
http://velonews.competitor.com/2008/04/road/team-slipstream-chipotle-hits-paris-roubaix-on-special-felt-bikes_74577

[pumpkinpony]

Mine was doing that - I took it to the LBS and he 'roughed' up the seat tube and put a friction compound on it. Worked well!

[PamNY]

I really wanted the hose clamp to work, but I have a classic NYC antitheft chain on my saddle. Can't take the saddle off and I couldn't get the hose clamp back together after I opened it up.

So I had no choice but to go the the LBS. This will forever be the mystery problem with a mystery solution. The very busy LBS fixed it while I waited (on a sunny Sunday afternoon). The mechanic speaks little English, and I speak little Spanish so we couldn't really communicate. They didn't charge me, so I didn't press the point, and hightailed it for Central Park.

Bike is fine now, and thanks for the suggestions. At least I know what they might have done.

[W15]

I had that isssue with a carbon seatpost and hairspray solved the problem! I borrowed hairspray from a woman in my office, sprayed it on, let it mostly dry then set the post to the appropriate height and let it dry completely and have not had an issue since.