How to prevent Saddle slip. Need some advice here

[Bateleur1]

I am having a problem that lately my saddle slips gradually backwards.  So during a ride I notice that I am sitting much further backwards and eventually I will notice discomfort in my lower back.  Now I am tightening the bolts at the recommended torque (9Nm).  And I have tried applying carbon paste which did help to some extend but the moment when I do more climbs, I obviously push back a bit more on the saddle and it ever so slightly starts slipping backwards.  It is alliminium rails, not carbon.  Should I simply add a few Nm of torque?

[MudLark]

Odd. Are your seat rails  not too narrow for the channel width?

[David Marshall]

Some carbon rail saddles have a different shaped clamping mechanism to the alloy ones.  Check that you have the right rail/clamp combo.  If this is right then you can apply something gritty to the rail when clamping (like Vim).

[MrJacques]

I've had that as well... ended up bending / breaking the rails

 

Maybe some Loctite could help?

[Martin PJ]

I had a problem with a crankbrothers seat post clamp once, there was a piece missing in the center of the seat post clamp that applied lateral pressure to the rails.

 

On a carbon seat I couldn't clamp the rails very tight, so I cut small squares of sandpaper which I used between the clamp and the rail, not ideal, but it did work.

[Bateleur1]

Thanks for the info so far.  Just to re-itterate. It is not carbon rails but alliminium (or some alloy).  It is the original seat post / saddel combination that came with the bike.  Fizzik saddle.  Carbon seatpost.

[MORNE]

put some carbon assembly compound where it all comes together ? The grit might be enough to give it some friction not to move. Some do that to seat posts in metal frames too to limit clamping force needed, especially on droppers.

 

PS: you might end up with a creak or two though, why I hate the stuff

[Bateleur1]

put some carbon assembly compound where it all comes together ? The grit might be enough to give it some friction not to move. Some do that to seat posts in metal frames too to limit clamping force needed, especially on droppers.

 

PS: you might end up with a creak or two though, why I hate the stuff

 

I have tried that and have had some success with it as it did last quite bit before the slipping started. On Sunday I went for a long ride which included quite bit of a long climb and eventually on my return home I noticed the seat had moved somewhere along the way.  It is not a sudden slip it is very gradual.

[Bateleur1]

Has this only started happening recently or is some part new? Did it start by itself? I understand David's question. But answering the above may help. Did you disassemble it or something? 

 

Started fairly recently.  No new parts.  Started by itself.  No disassembling of any kind.

[Bateleur1]

Hells bells. That is weird then. I guess in my opinion I would just tighten the bolts a bit more. I would lend you a seat post but then you are not really around the corner.

 

Very.  That is why I posted the question.  I will propably end up tightening the bolts more but just wanted to throw it out there and see maybe someone has had a similar problem.  The sand paper idea might not be too bad as well.

[SwissVan]

Very. That is why I posted the question. I will propably end up tightening the bolts more but just wanted to throw it out there and see maybe someone has had a similar problem. The sand paper idea might not be too bad as well.

Alloy Seat rails should not need any kind of substance to prevent slipping. The contact surface of the clamp is large enough to stop slipping provided it is tight enough.

 

Just tighten them more, without the torque wrench.

[Thomo]

Now I am tightening the bolts at the recommended torque (9Nm).

Can the torque wrench be trusted.?

Maybe tighten a little bit more ...

[RobertWhitehead]

Here's my solution if the additional torque does not do the job: 

 

Put two strips of sponge tape (similar to double sided tape but only one-sided)  . on the contact points between the rails and clamp 

[SwissVan]

Alloy Seat rails should not need any kind of substance to prevent slipping. The contact surface of the clamp is large enough to stop slipping provided it is tight enough.

 

Just tighten them more, without the torque wrench.

Maybe the bolts are bottoming out on the shank when you tighten them, did you perhaps loose the washers that go under the bolt head?

 

In other words they feel tight but are not really tight

[Mongoose!]

What brand bike is it?

 

Will you be able to sit on the top tube if the saddle is out of position during a ride?

[dewaldsss]

maybe it needs to be epoxied in place....