Advertise on Bikeforums.net



User Tag List

Results 1 to 16 of 16
  1. #1
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)

    Seat post sliding down in the seat tube... Any tips?

    Seat post sliding down in the seat tube... Any tips?
    Every several miles it goes down inch or so. I'm using QC clamp, cleaned all the old grease from seat post and tube... I can't tight clamp any harder ...
    I'm a pretty heavy rider ( 260 or so ) and this bike is used mostly on flat and not bumpy trails.
    Years ago, I remember that all seat posts were machined to file like finish. New ones are shiny and "slippery".
    I'm using older rockshox suspension seat post with very slippery finish...
    Any tips?
    Thanks!
    Attached Images Attached Images
    Last edited by lopek77; 11-18-11 at 07:59 PM.
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

  2. #2
    Senior Member Shimagnolo's Avatar
    Join Date
    May 2008
    Location
    Zang's Spur, CO
    Posts
    6,385
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You could try this: http://www.universalcycles.com/shopp...s.php?id=30551
    It contains a gritty component so you don't need as much torque on CF parts to keep them from slipping.
    I used it between the head/bar-mount a headlight that wouldn't stop slipping out position and it worked like a charm.

  3. #3
    Can'tre Member 3alarmer's Avatar
    Join Date
    Nov 2010
    Location
    ,location, location...
    My Bikes
    old ones
    Posts
    7,980
    Mentioned
    143 Post(s)
    Tagged
    4 Thread(s)
    Rough your post with coarse abrasive like 80 grit sandpaper?

    Are you certain you have the proper diameter post given
    your bicycle's tubing? If this is a replacement post, they
    are often sized wrong and will slip.
    Quote Originally Posted by Terrierman View Post
    No wonder everybody hates you.

  4. #4
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Shimagnolo View Post
    You could try this: http://www.universalcycles.com/shopp...s.php?id=30551
    It contains a gritty component so you don't need as much torque on CF parts to keep them from slipping.
    I used it between the head/bar-mount a headlight that wouldn't stop slipping out position and it worked like a charm.
    I will try it second... Thanks for the link! Looks like it works for other people with the same problem.

    Quote Originally Posted by 3alarmer View Post
    Rough your post with coarse abrasive like 80 grit sandpaper?

    Are you certain you have the proper diameter post given
    your bicycle's tubing? If this is a replacement post, they
    are often sized wrong and will slip.
    It started happening lately, it's the right diameter. I will try sandpaper on both post and tube first, before trying the paste from previous post.
    Thanks guys!
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

  5. #5
    Member
    Join Date
    Jul 2011
    Location
    Vancouver, BC
    Posts
    46
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Spray the post with hairspray, let it dry over night and put it in.

  6. #6
    Senior Member
    Join Date
    Apr 2009
    Location
    New Rochelle, NY
    My Bikes
    too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
    Posts
    21,532
    Mentioned
    51 Post(s)
    Tagged
    1 Thread(s)
    grit paste will help, but you shouldn't need it. Take a minute to try to figure out why normal clamping doesn't hold. The first place to check is the clamp collar. Check it for distortion, and see of the backs of the ears touch each other, or if the sides of the slot in the seat tube close until they touch. Also see if the bole has a damaged thread, or if the bolt is bent when tight.

    Any of the above, especially the seat tube closing may indicate that the post is undersized for the frame. Or that the clamp collar is damaged.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  7. #7
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by tomecki View Post
    Spray the post with hairspray, let it dry over night and put it in.
    I heard that before...I have to talk to my wife first I guess ;-)
    Dzieki! Thanks!
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

  8. #8
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by FBinNY View Post
    The first place to check is the clamp collar. Check it for distortion, and see of the backs of the ears touch each other, or if the sides of the slot in the seat tube close until they touch. Also see if the bole has a damaged thread, or if the bolt is bent when tight.
    Or that the clamp collar is damaged.
    Thanks, I'm embarrassed... I didn't even think about checking the clamp itself... Will do it tomorrow morning for sure!
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

  9. #9
    Senior Member
    Join Date
    Sep 2010
    Posts
    2,783
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)
    lopek77: If it used to work and doesn't any more I'd carefully examine the clamp for cracking or deformation; a sudden failure could have unpleasant consequences. Be certain that there is a gap at the clamp opening so that the screw is applying tension to clamp the seat tube and not just closing the clamp on itself. You might also try cleaning and greasing the QR threads and cam so that you can easily adjust them. The clamp lever should rotate closed smoothly with steadily increasing pressure. You should adjust the clamp screw so that it takes considerable pressure to close the lever; it should leave a mark on your palm if it is tight enough.

    Edit: I see that FB beat me to it while I was typing.

  10. #10
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Yes he did dsbrantjr I'm glad to hear identical tips...sounds like that may be a problem. I will update this tread when I find out what was wrong, or what works to prevent slipping. Thanks!
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

  11. #11
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    1,423
    Mentioned
    32 Post(s)
    Tagged
    0 Thread(s)
    I must Assume the seatpost is the right diameter.. not undersized.
    A stainless steel band clamp, wont strip as soon as an aluminum one ,
    so you can tighten it more
    one with a steel barrel nut will also be more tolerant than one
    simply threaded directly in aluminum.

  12. #12
    Senior Member
    Join Date
    Nov 2009
    Location
    Boston area
    My Bikes
    1984 Bridgestone 400 1985Univega nouevo sport 650b conversion 1993b'stone RBT 1985 Schwinn Tempo
    Posts
    732
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    It the seatpost is undersized you can try a shim made out of a beer or soda can.

  13. #13
    Senior Member Gravity Aided's Avatar
    Join Date
    Oct 2011
    Posts
    2,564
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've used Ironwoods' idea before on a Schwinn Prelude with odd-sized seat tube, and it worked great. I'm just a little north of 260.

  14. #14
    Member
    Join Date
    Jul 2011
    Location
    Vancouver, BC
    Posts
    46
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by lopek77 View Post
    I heard that before...I have to talk to my wife first I guess ;-)
    Dzieki! Thanks!
    Czesc Lopek,

    My girlfriend won't let me use her good stuff. I have to settle for her reject can. Not that it matters.

    I recently had the same problem with a new carbon post. I ended up finding a bunch of advice in some old thread and combined a few of the suggestions. I gently buffed the bottom of the post and the inside of the seat tube with 180 grit. Then I gave it a couple of coats of the hairspray. Let it cure over night, and dusted it with climbers chalk before I put it in. It worked like a charm.

    Powodzenia!

  15. #15
    Senior Member
    Join Date
    Dec 2005
    Posts
    7,819
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    1st time i heard about hairspray well that thing is pretty sticky and is like a cheap clearcoat, interesting

  16. #16
    "LOGIC!" lopek77's Avatar
    Join Date
    Sep 2010
    Location
    SE MICHIGAN
    My Bikes
    10 Specialized Crosstrail, 09 Raleigh Mojave 5.0, 70's Panasonic DX-2000, 70's Schwinn world traveler (originally owned by Prady family - "The Big Bang Theory") , 96 Mongoose switchback, 80's Romet Wigry 2, 80's Romet Wigry 3, Romet Pelikan...
    Posts
    1,034
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I did over 28 miles last night in 23F weather. Seat post didn't slide down at all...I just adjusted QC clamp. Looks like it was not sitting the right way on the seat tube ( a lot of night rides lately and it was hard to see anything ).
    Thanks again for all tips and when I have some more time I will use some sandpaper and hair spray trick to make sure it will never slide down again ;-)
    Attached Images Attached Images
    "The clear problem of the outlawing of insult is that too many things can be interpreted as such. Criticism, ridicule, sarcasm, merely stating an alternative point of view to the orthodoxy, can be interpreted as insult." - Rowan Atkinson
    Cycling Videos

Posting Permissions

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