Seat post keeps dropping over time.

avalanche_expert
avalanche_expert Posts: 177
edited August 2015 in MTB workshop & tech
I've had my current bike for almost 3 months. Brand new GT, with the supplied GT seat post & GT QR lever. After a couple of rides I have to re adjust my post height, as it can drop as much as 5 - 8 mm depending on the length of my rides and the terrain.

I'm only 10 and a half stone, I've checked that it's not over greased and I've adjusted the quick release lever numerous times. If I had it any tighter I wouldn't be able to operate it by hand.

Any tips? Perhaps a complete de grease and re grease with something else? Or could the GT quick release lever be a bit pants? I don't want to go buying fancy QR levers unless I know it's that to blame.

Thanks!

Comments

  • codfather
    codfather Posts: 359
    Measure the diameter of the seatpost with a vernier, could be fractionally below the stated diameter.
    Current fleet
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  • avalanche_expert
    avalanche_expert Posts: 177
    I haven't got access to a vernier today but with a ruler it measures 31mm, the post has 30.9mm stamped on it. I'd say it's probably within tolerance.
  • heez29
    heez29 Posts: 612
    Use copper grease or fibre grip. Both will act like an anti seize as well as provide friction for the seatpost.
  • The Rookie
    The Rookie Posts: 27,812
    edited July 2015
    Copper grease is guaranteed to make it worse, carbon gripper paste will help a lot, also lube the cam face on the QR, if that is dry and gritty it pushes lever effort right up so you can't close it and create the right clamp load.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • avalanche_expert
    avalanche_expert Posts: 177
    I'll look into carbon gripper paste thanks and I'll re grease the QR. I have cleaned and greased the QR a couple of times, but in no time it's covered in crud again.

    I'll get some carbon paste and report back.
  • youeee
    youeee Posts: 6
    I had the same issue with my post slipping. I simply replaced the QR and all is fine
  • The Rookie
    The Rookie Posts: 27,812
    Don't use grease, it attracts dirt, clean and a little drop of oil, wiping off the excess.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    If you have an external cam QR pop a little grease on there and it'll take much more force more easily
  • The Rookie
    The Rookie Posts: 27,812
    Of course, if the bushing the cam bears on is shot, nothing will now save it!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • avalanche_expert
    avalanche_expert Posts: 177
    Just thought I'd update on my seat post issue. I've replaced the the QR clamp with a bolt through type. I have no need to keep on adjusting seat height. I'm not a DH rider so once seat height is set I like to keep it that way, so QR seems pretty pointless to me I guess.

    Anyway with the new clamp I've had no slippage issues, so the original clamp must of been pants.

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