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Slipping seatpost(6 posts)

Slipping seatpostKurt H
Jan 12, 2003 9:40 AM
Hi folks,
This one maybe should go to the components board, but I'll try it here first since it deals with vintage equipment. I'm using a Campy NR/SR era (not sure exactly what model, since I pulled it out of the LBS' parts bin a coupla years ago - single bolt fixing with the fluting up the sides) single bolt seatpost with a Brooks B-17 saddle. The seatpost always slipped a little, letting the saddle nose slowly come up over time. Since I added a Carradice to the saddle the other day, the added weight at the back of the saddle has caused the problem to get worse. As it is, I tighten the fixing bolt to the point that I'm afraid of damaging the rails. Anybody got a good idea for getting these not to slip, or should I just start shopping for one of the two bolt seat posts from that era?
Thanks,
Kurt H
The CLAMP is slipping?Silverback
Jan 13, 2003 8:48 AM
I still have a bunch of one-bolt posts (by the time I buy a new bike, the old one's not worth much, so I just hang it in the garage and use it as a beater and parts supply), and I've never had a clamp slip. Off the top of my head, I'd try greasing the bolt well so you can tighten it, REMOVING any grease from the clamp itself (I know, it bothers me,too, but...), and maybe a new bolt (they can stretch, although I'd be surprised it it has).
I can't quite picture that precise post, but if it has two smoothish surfaces (non-milled or otherwise grooved to engage each other), you could try putting a fine abrasive between them. They used to use automotive valve-grinding compound for stuff like that. Probably grind up the clamp eventually, but you can't use it the way it is anyway.
To clarify, yes...Kurt H
Jan 13, 2003 5:03 PM
the clamp is slipping by pivoting and letting the nose of the saddle rise. The two pieces that clamp the rails do a fine job of holding the saddle and keeping it from sliding back and forth. But the surfaces where the bottom of the clamp meets the seat post base are both smooth and are allowing rotation. I'll try the items above and see how it does. Thanks!!
Kurt H.
another place to put a dab of grease . . .micha
Jan 13, 2003 5:03 PM
. . . is the underside of the bolt head.

Sometimes the friction between the underside of a bolt head and whatever it makes contact with keeps the bolt from being tightened properly. It "bottoms out," so to speak, on it's own friction, instead of pulling the clamp tight.
Try turning the clamp assembly around?Dave Hickey
Jan 14, 2003 7:39 AM
Have you tried turning the whole clamp assembly around? Don't ask me why it works but it solved my slipping problem on an old Campy post.
I'll try that and let you know. Thanks! - nm.Kurt H
Jan 14, 2003 8:49 AM