Results 1 to 10 of 10
  1. #1
    mtbr member
    Reputation:
    Join Date
    Oct 2017
    Posts
    191

    Seat Clamp Biting Into Seat Tube

    Hi all,

    I recently pulled my dropper and seat clamp for some cleaning after a particularly muddy ride. I noticed that the edge of the seat clamp where the screw is tightened seems to be biting into the top of the seat tube a bit (the part that is normally covered by the seat clamp).

    When running my finger over the area I can definitely feel a small indentation where the edge of the clamp was. Is this normal and acceptable, and if not, what should be done about it? I can get some photos to help explain it better.

    Thanks for any help.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Oct 2018
    Posts
    22
    Hi - your issue is just a build quality issue, which you can fix. Assuming you have a steel or aluminum frame, the entry point of the seat tube is probably flared in too much. Or it could be the clamp has sharp edges where it pinches together. With the seat post removed, take a broom handle and gently flex the outside of the tube and you should see the split in the seat tube start to open up. You can then take a small fine round file or some fine sand paper wrapped around a round tool and sand/file away the sharp edges. Do this for the clamp if needed as well.

    Hope that helps.
    Mike

  3. #3
    mtbr member
    Reputation:
    Join Date
    Oct 2017
    Posts
    191
    Hi,

    Thanks for the recommendations. I've got my clamp set up so that the screw side is at the back of the seat tube (opposite side to where the seat tube split is). I'll try to get and upload some photos tomorrow to help clarify.

    It sounds like the seat clamp might have a slight sharp edge on the inside near the clamping screw, I'll definitely have a go at it with some sandpaper. Hopefully that will help flatten it out and prevent it digging into the seat tube.

    Thanks again.

  4. #4
    since 4/10/2009
    Reputation: Harold's Avatar
    Join Date
    Dec 2003
    Posts
    24,402
    The vast majority of seat clamps I've seen are positioned where the split in the clamp lines up with the split in the seat tube. According to Salsa, this is the correct orientation for their seat collars.

    https://salsacycles.com/files/tech/1...lar_INST_F.pdf

    Not that that would necessarily be causing the gouging you're seeing.

    This sort of thing isn't necessarily uncommon, but it's definitely not supposed to happen. I'd hit it with a file to take the sharp spot out, personally.

    Only somewhat related - I worked at a shop for a little while that would hit every new frame for a second with a flex hone inside the seat tube to ensure that all the burrs were removed (particularly around the top of the seat tube) and that seatposts could be inserted/removed freely.

  5. #5
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    9,262
    As Harold alluded, seatpost clamp openings and frame seattube slots are typically lined up. I always assumed this was de rigueur until I recently read instructions that came with a clamp that instructed the openings should be 180 degrees opposite one another only when clamping a carbon fiber seatpost. But that's the only time the components should be assembled this way.

    OP, I know this doesn't address your specific question but it seems appropriate to mention based on the information you provided. Then again maybe you're clamping a CF seatpost.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  6. #6
    mtbr member
    Reputation:
    Join Date
    Oct 2017
    Posts
    191
    Sounds good, I'll try the clamp with it aligned with the seat tube slots. I heard that running the clamp 180 to the slot helped spread the clamping force, but since I'm running an alloy frame with an alloy post (dropper) it probably doesn't matter. I've also heard people recommending greasing the clamp, would this help at all? I'm also thinking about trying a higher quality clamp (something like Hope or Salsa) as well.

    Thanks for the advice.

  7. #7
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    9,262
    Quote Originally Posted by Phoenix864 View Post
    Sounds good, I'll try the clamp with it aligned with the seat tube slots. I heard that running the clamp 180 to the slot helped spread the clamping force, but since I'm running an alloy frame with an alloy post (dropper) it probably doesn't matter. I've also heard people recommending greasing the clamp, would this help at all? I'm also thinking about trying a higher quality clamp (something like Hope or Salsa) as well.

    Thanks for the advice.
    I always grease metal-to-metal contact points unless instructed not to.

    As for dropper posts, typically a light coating of friction paste is preferred where grease is employed for static length posts.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  8. #8
    since 4/10/2009
    Reputation: Harold's Avatar
    Join Date
    Dec 2003
    Posts
    24,402
    Quote Originally Posted by Sparticus View Post
    I always grease metal-to-metal contact points unless instructed not to.

    As for dropper posts, typically a light coating of friction paste is preferred where grease is employed for static length posts.
    =sParty
    I've learned that not all friction paste is created equally.

    I've used some stuff with fairly large grit particles in it that seems to create creaking noises (pretty sure it's the Tacx brand), so I try to buy friction paste with especially fine particles in it now. I haven't bought any in awhile, so I've lost track of which brand(s) I prefer.

  9. #9
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    9,262
    Quote Originally Posted by Harold View Post
    I've learned that not all friction paste is created equally.

    I've used some stuff with fairly large grit particles in it that seems to create creaking noises (pretty sure it's the Tacx brand), so I try to buy friction paste with especially fine particles in it now. I haven't bought any in awhile, so I've lost track of which brand(s) I prefer.
    Iím using Park Tool brand friction paste but donít have anything to compare it to. Anyway it seems to work well enough.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  10. #10
    mtbr member
    Reputation:
    Join Date
    Oct 2017
    Posts
    191
    So I flipped the clamp and tossed some grease around the top of the seat tube. After a quick ride I noticed that the post slipped a bit at 4nm; I'm now trying 4.5nm and will be picking up some friction paste.

    One thing about the seat clamp is that aligning the opening in the clamp to the slot in the frame causes the clamp to be off center. I guess when Kona was designing the clamp they intended it to be run with the bolt in the back. I'm a bit OCD about alignment, so it looks like I'll be picking up a new seat clamp (something shiny out of Salsa or Hope looks to be the future).

    I've also attached a quick photo of the slight depression in the seat tube. It's very subtle, but is definitely noticeable when running a finger over the tube.

    Thanks for all the advice.

    Seat Clamp Biting Into Seat Tube-seatclamp.jpg


    Seat Clamp Biting Into Seat Tube-seattube.jpg

Similar Threads

  1. Replies: 7
    Last Post: 09-16-2016, 05:51 AM
  2. Seat post min insertion into a frame with seat tube brace question
    By Strife21 in forum Bike and Frame discussion
    Replies: 1
    Last Post: 07-24-2015, 09:36 AM
  3. Seat tube, top tube, head tube deal
    By calstar in forum Frame Building
    Replies: 0
    Last Post: 08-29-2013, 10:12 AM
  4. How do you keep off those biting flies in CB...and from biting?
    By SingleTrackHound in forum Colorado - Western Slope
    Replies: 24
    Last Post: 08-07-2008, 09:49 AM
  5. Thomson Seat Clamp - Seatpost Clamp - Seat Post Clamp
    By tvrbob86 in forum General Discussion
    Replies: 2
    Last Post: 05-02-2008, 09:22 AM

Members who have read this thread: 46

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.