I can’t seem to be able to keep my saddle from slipping on the rails from moving backwards when I ride. I tighten the nuts as tight as I can, and if I “strike” the saddle while I’m off of it just to see if it moves, it doesn’t. So, I go on a ride, and then notice it slips about 1/2 - 1cm backwards. I know because I marked the position with a pen. Then I have to re-position the seat after every ride.
It’s an aluminum stock cervelo post with a adamo saddle if that matters.
Most problems on a bike can be fixed with either tub tape, insulation tape, duct tape or a small piece of Coke can!
In this case, I’d try wrapping a small bit of tub tape around the saddle rail to give it some extra grip.
Might also be worth getting your position checked out too. Sounds like you’re putting plenty of horizontal force on the saddle?
Thanks for the tips for the extra grip. Can you elaborate on the possible problem on the “horizontal force” idea?
Most problems on a bike can be fixed with either tub tape, insulation tape, duct tape or a small piece of Coke can!
In this case, I’d try wrapping a small bit of tub tape around the saddle rail to give it some extra grip.
Might also be worth getting your position checked out too. Sounds like you’re putting plenty of horizontal force on the saddle?
Without seeing your position or seeing you ride it’s hard to say, but you normally need a fair bit of force to shift a saddle in the seat clamp.
Either your seat clamp just isn’t up to the job (unlikely as there are gazillions of Cervelo owners in the world and if there was a problem with Cervelo seat clamps the whole world would have heard about it by now from forums just like this one) or something about your position or riding style is putting plenty plenty backwards force onto the saddle when you ride (more likely I would have thought).
Huh…I’ll have my positioned checked out again. Thanks again for the info.
+1 on the tape. Electrical or otherwise, tape will help with grip AND make the rail fatter (is it too skinny for the saddle clamp??)
Tighten the saddle clamp bolt until it breaks…then back it off half a turn.
All joking aside, is the screw loose when you experience this? If so use locktite. You could also roughen the finish of the contact surfaces with sandpaper (i also have an Adamo and the rails are highly polished).
The screw is not loose. I’ll try the tape and/or sandpaper idea. I think maybe like itcaesar said, maybe the rail is too skinny for the clamp.
I cut a small strip of beer can and used it as a shim. Problem solved. Careful, its sharp.
I don’t get it. You wrapped the beer can around the saddle rail?
That’s my kind of fix, 'cause I have to empty the beer can first…! Woo hoo! 
That is exactly what I did. Cut a small strip out of the can, wrapped it around the saddle rail, then tightened the seatpost clamp. Took care of the problem, and yes, the best part was emptying the can first.
Cool, that might be more stable than the tape idea, plus I get a beer at the same time.
It could be that you’ve stripped the piece of crap seatpost head. Don’t ask how I know that this is easily possible. So you crank and crank and think it’s tight. But it’s really not getting any tighter…
Now that I think about the last time I tried tightening it, I thought it did keep turning. But then all of a sudden, it did “catch.” I’m going to check it out right now. I can just get a nut if this is the case, right?
Tighten the saddle clamp bolt until it breaks…then back it off half a turn.
All joking aside, is the screw loose when you experience this? If so use locktite. You could also roughen the finish of the contact surfaces with sandpaper (i also have an Adamo and the rails are highly polished).
I know you were joking but I’ll be damned if this didn’t happen to me today.
I was 3 mi. into my ride when it felt like the seat tongue was tipping down. I pulled over and, sure enough, the bolt was loose. I re-adjusted the seat and tightened the bolt until SNAP! I didn’t put that much torque on it, either. Had to walk back.
I’ve had problems with this seat/post set up since last year. I think it may have cost me a podium spot when it came loose during a race. >-|
I went out for a 30 miler today and mine didn’t snap but the adding something to stop it from slipping, didn’t work. I think I might have a stripped bolt or stripped “where the other bolt goes into” area. Mine just kept sliding until it was way back and I came home with a sore lower back.
I wonder if the “newer” model is any better. I just saw the description on excelsports saying it’s a newer model but not sure if it addresses our problem or what it means by “more secure.” Maybe there’s another seatpost we can use but I think we might be sol on this one to have to buy OEM parts.
Actually, I was on my Spec. Allez today. It’s the bike I raced last year and had the problem with. The seat post on my 2007 Cervelo appears to be the same as the one you found online. It has the PD TriStryke seat and I have not had a problem with it coming loose. But, I also only have about 200 miles on the bike.
I did notice that if I pushed the seat on the Allez too far forward that the clamp would bind in the bend on the seat rails. Make sure you don’t have it jammed too far forward.
Just in case someone does a search later on, I’m going to put what finally worked for me. The tape and beer can “wrap” did not work for me. Though for the can, I used a coke zero can instead so not sure if that was why it didn’t work Anyways, what eventually worked was I sprayed some hairspray on the rails and tightened the bolt and waited overnight. I rode the next day and it seems to work. The weekend will be the big test as I’ll go for a long ride but it seems to hold for now.
I have basically all the vintage Cervelo clamps.
One particular model needed some material taken from the sides to create more clearance. My guess if you can tighten all you want…or put in a shim, but those won’t create the necessary space.
Take a look around your set-up and I bet you’ll find the clamp is bottoming out on itself.