Results 1 to 11 of 11
  1. #1
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180

    Caution;  Merge;  Workers Ahead! 2011 Scalpel seat post/ seat clamp issue

    Hi everyone! Just upgraded the 2010 Scalpel frame to 2011 Scalpel Team frame. When I placed the 31.6mm Thomson seatpost into the seat tube and tightened it, I found that the seatpost was very loose inside the seat tube...If I released it by my hand, it just dropped down into the seat tube......Then I try to tightened the seat clamp.......I tightened it by 5Nm torque wrench......but it wouldn't stop........the clamp have just been tightened like what the photo showed. Then I went for a short ride, the seatpost just dropped down by about 1 inch!! I felt that the seatpost wasn't well secured.....I tried to put another seat post, 31.6mm KCNC seat post.....resulted the same......what's wrong with it? What's going on? Is it normal? Please Help...........Thanks!
    Attached Thumbnails Attached Thumbnails 2011 Scalpel seat post/ seat clamp issue-010820112322.jpg  


  2. #2
    mtbr member
    Reputation:
    Join Date
    Apr 2011
    Posts
    497
    I don't have experience of Scalpels, so can't comment on that specifically but do you have any carbon paste in the seat tube? That will help the seatpost stay put at lower clamping force (it makes a surprising difference), also grease under the clamp itself (between the clamp and outside of the seat tube only) will help spread the tightening force evenly around the seat tube top and grip the post better as you tighten the clamp.

    Having said that, it looks like your seatclamp is done up almost to the limit? (is it?) I've had this problem on a used frame I bought where the seattube was "27.2" but it was so loose you could fit a 27.4 in there and I could never get a 27.2 to clamp tight enough not to slip. In fact, the solution in that case was to buy a 27.4 post for it.

    That was for a cheap, used frame though, I don't think this is any sort of solution on a frame of this quality. If the carbon paste / grease doesn't work, I'd be talking to the place you bought it from...

  3. #3
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180
    Thanks for the advice! ....Also, some people said that the original Cannondale seat clamp was too weak to hole the seat post.....would it be the problem as well? Thanks! Really want to solve this problem.....Really an headache....don't know which way is the best......

  4. #4
    mtbr member
    Reputation: Midgetman's Avatar
    Join Date
    Feb 2011
    Posts
    199
    Does the seatpost just slide down into the tube if you don't tighten the clamp or has it play so that you can move it to the sides, to and fro as well? If the latter is the case I think you either need another seatpost diameter, or -which is more likely since the Scalpel officially takes 31.6 seatposts as far as I know- you have to have your frame exchanged.

    Otherwise do as jimification has suggested and apply some carbon paste (don't use grease where carbon fiber is involved!).

    The Cdale clamp works fine with me, but I use a carbon seatpost which generally causes less low-friction problems than carbon/aluminum combinations.

    Good luck!

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180
    Quote Originally Posted by Midgetman View Post
    Does the seatpost just slide down into the tube if you don't tighten the clamp or has it play so that you can move it to the sides, to and fro as well? If the latter is the case I think you either need another seatpost diameter, or -which is more likely since the Scalpel officially takes 31.6 seatposts as far as I know- you have to have your frame exchanged.

    Otherwise do as jimification has suggested and apply some carbon paste (don't use grease where carbon fiber is involved!).

    The Cdale clamp works fine with me, but I use a carbon seatpost which generally causes less low-friction problems than carbon/aluminum combinations.

    Good luck!
    The seatpost did slide down into the tube if I didn't tighten the clamp..and it played to and fro as well.....I tried few seat post.....Thomson, KCNC, X-Cross and Easton EA70.....all failed!!! They are all 31.6mm in diameter! Should i just wrap a very thin , like 0.1mm sticker tape onto the seat post? All advices are welcome!! Thanks!!

  6. #6
    mtbr member
    Reputation: Midgetman's Avatar
    Join Date
    Feb 2011
    Posts
    199
    Quote Originally Posted by scalpel226 View Post
    Should i just wrap a very thin , like 0.1mm sticker tape onto the seat post?
    That's a bummer. I wouldn't go for the sticky tape solution because 1) a freaking expensive frame like the Scalpel should have a precisely milled (or molded) seat-tube 2) the solvents in the adhesive might damage the carbon composite (if there is no clear coat or similar applied in (!) the seat-tube. So if you cannot get a new frame (because you bought this one 2nd hand - in this case I'd ask the previous owner what they did to keep the post in place) painting the inside of the seat-tube with a carbon composite friendly paint would probably be the best solution.

    If it's a new frame, Cannondale have to take it back. This is not acceptable.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180
    Quote Originally Posted by Midgetman View Post
    That's a bummer. I wouldn't go for the sticky tape solution because 1) a freaking expensive frame like the Scalpel should have a precisely milled (or molded) seat-tube 2) the solvents in the adhesive might damage the carbon composite (if there is no clear coat or similar applied in (!) the seat-tube. So if you cannot get a new frame (because you bought this one 2nd hand - in this case I'd ask the previous owner what they did to keep the post in place) painting the inside of the seat-tube with a carbon composite friendly paint would probably be the best solution.

    If it's a new frame, Cannondale have to take it back. This is not acceptable.
    This is a brand new 2011 Scalpel Ultimate frame I bought from the LBS 3 weeks ago!!.....Let me try the method suggested above .........I will put some carbon paste and have a go and see.....Thanks!

  8. #8
    mtbr member
    Reputation:
    Join Date
    Apr 2011
    Posts
    497
    The carbon paste should make quite a difference. It's looks a little like grease but it has fine granules in...makes a terrible scraping noise when you slide the post in with it but it takes up the gap very well. The one I use is Finish Line "Fibre Grip" / "Fiber Grip"

    The seatpost / seattube on my new 29er Flash Carbon is a fairly loose fit too - the SAVE post (27.2) will drop down a little way pretty much on it's own but it fits quite well - you can't "rattle" it side to side like you describe.

    If the seattube actually IS too big, then I think there may be other issues to take into account:-

    1)You would actually be putting more clamping "movement" on the top of the seattube: You are trying to reduce it in size more than it should go normally if it was a slightly smaller diameter. Bear in mind that the clamp just reduces the size of the top 1/4 inch of the seattube, not the whole thing. Clamping this thing down more than it's supposed to move might be bending it in a bit too far

    2) The seatpost is not properly supported in the seattube: Normally, the seatpost is tight up against the inside of the seattube and when you sit on the saddle, the load is spread from the front of the section of post that is inside the tube to the corresponding area of the seattube. If the seattube itself is much too big, then, assuming that the post doesn't bend, just the very bottom of the post will be pressing against a small area at the front of the seattube. Also this area is probably lower down than the support it would normally have around the top tube junction because the load isn't spread properly...

    This is all just my guess so take it with a pinch of salt but on top end race frame like this (one of, if not the lightest FS frame made) they remove every ounce of material they can to save weight and it's only strong if everything is used exactly right.... I think I would definitely be talking to your LBS about this and possibly asking for an exchange...it's not worth the nagging doubt just for a small delay in getting it built up...
    Last edited by jimification; 08-01-2011 at 07:21 AM.

  9. #9
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180
    Quote Originally Posted by jimification View Post
    The carbon paste should make quite a difference. It's looks a little like grease but it has fine granules in...makes a terrible scraping noise when you slide the post in with it but it takes up the gap very well. The one I use is Finish Line "Fibre Grip" / "Fiber Grip"

    The seatpost / seattube on my new 29er Flash Carbon is a fairly loose fit too - the SAVE post (27.2) will drop down a little way pretty much on it's own but it fits quite well - you can't "rattle" it side to side like you describe.

    If the seattube actually IS too big, then I think there may be other issues to take into account:-

    1)You would actually be putting more clamping "movement" on the top of the seattube: You are trying to reduce it in size more than it should go normally if it was a slightly smaller diameter. Bear in mind that the clamp just reduces the size of the top 1/4 inch of the seattube, not the whole thing. Clamping this thing down more than it's supposed to move might be bending it in a bit too far

    2) The seatpost is not properly supported in the seattube: Normally, the seatpost is tight up against the inside of the seattube and when you sit on the saddle, the load is spread from the front of the section of post that is inside the tube to the corresponding area of the seattube. If the seattube itself is much too big, then, assuming that the post doesn't bend, just the very bottom of the post will be pressing against a small area at the front of the seattube. Also this area is probably lower down than the support it would normally have around the top tube junction because the load isn't spread properly...

    This is all just my guess so take it with a pinch of salt but on top end race frame like this (one of, if not the lightest FS frame made) they remove every ounce of material they can to save weight and it's only strong if everything is used exactly right.... I think I would definitely be talking to your LBS about this and possibly asking for an exchange...it's not worth the nagging doubt just for a small delay in getting it built up...

    Really thanks for the great advice!! I borrow a Hope seat clamp from my friend and try in on my frame.....Surprisingly, the KCNC seat post doesn't slide down on its own.....Then I tighten the bolt....it holds the seat post really well this time.....and with less effort.....

  10. #10
    mtbr member
    Reputation: Midgetman's Avatar
    Join Date
    Feb 2011
    Posts
    199
    Quote Originally Posted by jimification View Post
    2) The seatpost is not properly supported in the seattube:
    Make sure that the KCNC post doesn't have any play when the seat collar isn't tightened. Everything else would mean substantial fatigue for both frame and post.

    Just using a stronger seat collar to make up for insufficient post/seat-tube fit is like using a 25.4mm mtb bar with a 26mm road stem. It will work some time, but sooner or later your dentist can buy that new Supersix Evo you wanted to buy yourself...

    If the post doesn't have any play: great, problem solved. Hope parts rule anyway.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jul 2006
    Posts
    180
    Quote Originally Posted by Midgetman View Post
    Make sure that the KCNC post doesn't have any play when the seat collar isn't tightened. Everything else would mean substantial fatigue for both frame and post.

    Just using a stronger seat collar to make up for insufficient post/seat-tube fit is like using a 25.4mm mtb bar with a 26mm road stem. It will work some time, but sooner or later your dentist can buy that new Supersix Evo you wanted to buy yourself...

    If the post doesn't have any play: great, problem solved. Hope parts rule anyway.
    Once I used the Hope seat clamp, the play reduced when the clamp is not tightened. It didn't slide down anymore. I may apply some carbon paste as well.....hope the problem solved.....Thanks everyone!

Similar Threads

  1. Replies: 1
    Last Post: 08-23-2010, 02:33 AM
  2. Replies: 3
    Last Post: 08-19-2010, 07:19 PM
  3. Seat Post to Seat Clamp Table
    By Whafe in forum Nicolai
    Replies: 5
    Last Post: 07-24-2008, 08:10 AM
  4. Thomson Seat Clamp - Seatpost Clamp - Seat Post Clamp
    By tvrbob86 in forum General Discussion
    Replies: 2
    Last Post: 05-02-2008, 09:22 AM
  5. 05 Scalpel 2000 Seat Clamp Size?
    By Mud Muncher in forum Cannondale
    Replies: 1
    Last Post: 02-19-2006, 06:30 PM

Posting Permissions

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