Trek semi-integrated single bolt seat post slipping?

[Machoman121]

Anyone having any issues with the single bolt type of seat post on your carbon seat post? I imagine the single bolt to tighten the seat rails and hold it at the desired angle would not be strong enough to do the job - if you sit on the nose of the seat it will leverage the seat to angle down as the weight leveraged is too much for the friction/single bolt to work properly. Do you agree?

I've noticed this single bolt type of seat post is now very popular among TREK and Giant. I've got a Giant Defy 2015 SL1 which uses this type of seat post and my initial findings are that my saddle is not being able to be kept perfectly horizontal - the seat dips or angles down no matter how much i tighten the bolt. This is really bad as there's no option to change to another type of seatpost - it's an integrated type of seat post.

[wgc138]

you may not want to tighten it too much, since its semi integrated once its cracked...well its gone. Have you used carbon assembly lube? How has it gone down by?

[vindlecrag]

I have that post on my Boone and Emonda. Neither has ever slipped despite plenty of heavy cyclocross remounts.

Use carbon assembly past
Buy a torque wrench and use it.

From memory that bolt is 16nm. That's really tight. You're unlikely to go that tight without a torque wrench as you feel like it's going to break.

[bianchi928]

Hi Machoman,

Just to be clear, are you referring to the clamp that holds the saddle rails, not the actual post itself (both use one bolt for tightening)?

The sections that move in my Trek post and helps with the angle of the saddle are are plastic, not carbon, so not sure of carbon paste would help, although there are more educated guys than me on here in that regard.

If anything, my clamp wont move enough to make adjusting easy and definetly no slippage.

Cheers

[SEQrider]

I have a 2015 Domane and I also had the saddle come lose one day. It was after I had fitted a new saddle, actually I removed the Race saddle and fitted my old one. I tightened it back up on the road and then did it again with a torque wrench when I got home. Once tightened to the correct torque it hasn't moved. When I fitted the saddle I used a torque wrench but probably went a bit less than the reccomended torque, thinking it probably didn't need to be that tight but obviously it needs to set at the nominated torque. You really need a torque wrench these days, well worth the $ and you can get one for $70 or $80 that will last a life time.