Broken seat post bolts- help
Results 1 to 5 of 5
  1. #1
    RoadBikeReview Member
    Join Date
    Nov 2005

    Broken seat post bolts- help

    I have a 2010 Trek 5.2 Madone with the integrated seat mast with female seat post. Over the last 1.5 years I have been having problems with the seat post bolt snapping off at the bolt head. 3 times now. Quite annoying to get home. I have been using SS bolts and a torque wrench to put new ones in place.
    Is this a known issue ?
    Solutions ?
    Go to non-SS bolts to get stronger 12.2 steel ?

    I am not a big person. 145 lbs, 6' 1". Ride hills in Northern CA about 3500 miles a year and 350K ft climbing. Corrosion not an issue from water.

    Thanks for inputs !

  2. #2
    tlg is offline
    RoadBikeReview Member
    Reputation: tlg's Avatar
    Join Date
    May 2011
    How much torque are you using?

    Where are you getting your SS bolts from? Maybe they're poor quality.

    A 12.2 steel bolt would be more that 2x stronger. But you have to worry about it seizing from rust. And I'd be concerned that a 12.2 bolt will be so strong, that whatever is causing your bolts to break is going to cause something else to break instead.
    Custom Di2 & Garmin/GoPro mounts 2013 SuperSix EVO Hi-MOD Team * 2004 Klein Aura V

  3. #3
    RoadBikeReview Member
    Reputation: Tlaloc's Avatar
    Join Date
    May 2005
    If you lightly grease the threads it will help it tighten to the required torque and it won't seize. Or, since you shouldn't be removing this again, you could use blue locktite.

    The torque spec for this is only something like 60 inch pounds so it is surprising that the bolt would fail. Beware of over-tightening bolts on your carbon frame - you could damage the frame.

    Carbon assembly paste will keep the post from slipping.

  4. #4
    'brifter' is a lame word.
    Reputation: cxwrench's Avatar
    Join Date
    Nov 2004
    Carbon paste, grease the crap outta the bolt. Go 12.2 if you want. Why are you adjusting it so
    I work for some bike racers
    I've got some bikes, some guns,
    and a bunch of skateboards

  5. #5
    RoadBikeReview Member
    Join Date
    Nov 2005
    I torque to spec with torque wrench from bike shop.
    Bolts came from bike shop
    Not adjusting it often at all, the only time I have adjusted the bolt is when it has broken and had to put in new one.
    The bike shop has not been any help on defining a solution so that's why I thought I would try here.

Similar Threads

  1. Length of bolts on Vector Seat Post clamp
    By Italianrider76 in forum Giant
    Replies: 3
    Last Post: 05-24-2015, 02:02 PM
  2. Seat post bolts snapping
    By d64 in forum Components, Wrenching
    Replies: 14
    Last Post: 08-31-2009, 09:40 AM
  3. where to buy smaller seat post clamp bolts (old style)
    By StillKeen in forum Bikes, Frames and Forks
    Replies: 1
    Last Post: 11-23-2007, 05:26 AM
  4. seat-post clamp bolts - to grease or not?
    By acid_rider in forum Components, Wrenching
    Replies: 5
    Last Post: 06-04-2007, 03:42 PM
  5. anodized bolts/Ti bolts... bolts in general...
    By Cruzer2424 in forum Components, Wrenching
    Replies: 7
    Last Post: 02-16-2007, 06:56 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts




© Copyright 2019 VerticalScope Inc. All rights reserved.