[aka brad]

Well since I had to pry my last seatpost out of my bike, I made sure the new one was well greased. So far this has been a problem. I have not been able to keep the seatpost at the right height and have been steadly removing grease without any luck. Today I tried silicon grease and forgot my muti-tool (I don't have QR on my seatpost). One/half hour into a 2 1/2 hour ride the seat had dropped about 3/4 inch low, a couple more hits and it was 1 1/2 inches low. After that the ride became very tiring and painful. It would seem I keep my seat quite high and use a small range of motion when I'm grinding up a hill. With the seat so much lower I was using a different range of motion and my knees were screaming out in protest. I ended up standing a lot more than usual. Lesson learned.

I think my old seatpost stuck to the Framesaver in the seatpost tube. I have now cleaned both the tube and post and coated the post with chalk. I figure as long as I can remember to pull out the post once in a while to keep it clean I should be okay.

Still, I can't imagine those slalom/downhill guys riding around with their low seats.

1G1G, Brad

 

[Brandon]

Sounds like the new post is undersized, somtimes a seattube can be a little on the loose side and a post on the small side and you end up with slipping.

 

[wooglin]

When I first started riding my 1x1 with the Surly seat post binder I didn't grease the bolt and getting enough torque on it to hold the post was hard. Once I greased the binder bolt threads all was well. So that's another possibility.

I really dislike putting a seatpost in without grease. Makes me very nervous.

 

[Ziggy-Stardust]

I've had that happen before, pain in the arse. And then my alum seatpost got FUSED into the seat tube of my steel (old Trek) frame. And when I say fused I mean WELDED for good! It wouldn't come out, so I had to use an oxy/acet torch to melt the aluminum away and burn it out. Right now all I'm riding are alum bikes, so the seizing seatpost thing hasn't been a problem (yet anyway). But for whenever I ride steel again I've wondered what the best antiseize stuff is. I tried beeswax for awhile, which seemed to help some, but still led to some slippage.

I've often wondered if the ordinary copper based automotive antiseize compound used for exhaust manifold bolts would work. I'm sure it would prevent seizing, but not sure if it would stop the slippage (many of them are petroleum based).

 

[Guitar Ted]

Poor tolerances!

Usually all this seatpost slippage is due to poor tolerances right from the manufacturers. A poor combination will be especially troublesome. ( usually "cheap" seat posts) A really well made seatpost like a Thompson would be ideal, but not always affordable. One could use a little sandpaper on the inserted portion of the seatpost, lightly grease it, and tighten the binder as tight as you dare. Another remedy I've seen used is to mix in a small amount of dirt in with the grease used to put on the post. It works, but I really do not like that technique. My steel rigs require mondo tightness on the qr lever to hold my gravity loving carcass up! On the Surly, I have to tighten the binder bolt to 25 ft./lbs before it won't slip! Crazy, but it's been working for three years now!