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  1. #1
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    Carbon Flash slipping seatpost

    Anyone else having a problem with a slipping seatpost on a carbon Flash? I'm using a Thomson post in my 29'er frame and can't keep the post from slipping.

    Today at the shop we tried the carbon paste and made sure it was torqued to the proper spec printed on the clamp, 5 NM. We checked to make sure the clamp ends weren't touching. Still no luck.

    I wonder if a Salsa clamp would work any better?

  2. #2
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    Quote Originally Posted by skinl19
    Anyone else having a problem with a slipping seatpost on a carbon Flash? I'm using a Thomson post in my 29'er frame and can't keep the post from slipping.

    Today at the shop we tried the carbon paste and made sure it was torqued to the proper spec printed on the clamp, 5 NM. We checked to make sure the clamp ends weren't touching. Still no luck.

    I wonder if a Salsa clamp would work any better?
    It was the same for me, with the original collars, you need 6.2 NM to stop the seatpost.
    The problem is not the frame, but the collar. Don't worry, the 6.2 NM are not relocated on the seatpost, but on the collar deformation. With another collar stiffer than the original maybe the 5NM should be sufficient.

    Bye

  3. #3
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    are you sure to have rigth collar ?

    cannondale changed them in october 2009 to solve that problems

    be sure to have right version

    LEFT ONE is the new , the slimmest one is with issues
    Attached Thumbnails Attached Thumbnails Carbon Flash slipping seatpost-hpim0688.jpg  


  4. #4
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    Yes it's true, the mine is the right one.

  5. #5
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    I will have to check the collar. I didn't get the frame until January and the 29'er collars are black. But it still might be the old style. I turned the clamp around so that the bolt is on the other side of the post to see if that makes any difference.

    Once I removed the clamp and looked at the seat tube I don't think a Salsa clamp will work. The seat tube is narrower right under the clamp than the rest of the tube and flares out below the clamp. Salsa clamps are taller than the stock clamps so I don't think they will fit correctly.

    Eliflap or anyone else with the old and new clamps; can you measure the thickness of them so I can tell if mine is old or new? Thanks

  6. #6
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    Add some quality grease to the bolt thread and re-tighten. Worked for me, sounds strange but it did.

  7. #7
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    Quote Originally Posted by Dibbs_
    Add some quality grease to the bolt thread and re-tighten. Worked for me, sounds strange but it did.
    Grease the bolt but not the actual seat tube.

    Get some Tacx Carbon Prep and put it in the seat tube. This is a kind of grease that is carbon friendly that will help the seatpost grip the seat tube.



    http://www.competitivecyclist.com/ro...Paste_388.html

  8. #8
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    I had this problem with a Scott Scale Ltd. a few years back. They warranty replaced the whole frame.
    Emory Kalahari Kruiser

  9. #9
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    Quote Originally Posted by skinl19
    I will have to check the collar. I didn't get the frame until January and the 29'er collars are black. But it still might be the old style. I turned the clamp around so that the bolt is on the other side of the post to see if that makes any difference.
    skinl19, yours has to be the old version. The new version has a dimple on it that would prevent you from trying to reverse it.

  10. #10
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    Quote Originally Posted by amillmtb
    Grease the bolt but not the actual seat tube.

    Get some Tacx Carbon Prep and put it in the seat tube. This is a kind of grease that is carbon friendly that will help the seatpost grip the seat tube.



    http://www.competitivecyclist.com/ro...Paste_388.html

    agree !!

    i use Tacx on bread too for my breakfast : 190% more permormance in my training

  11. #11
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    Quote Originally Posted by wv_rider
    skinl19, yours has to be the old version. The new version has a dimple on it that would prevent you from trying to reverse it.

    dimple ?

    the dimple is in the frame

    collars , both old and new , have a pin
    Attached Thumbnails Attached Thumbnails Carbon Flash slipping seatpost-hpim0682.jpg  


  12. #12
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    if i may hijack the tread...

    does anyone with the USE 'save' seat post suffer with constant saddle angle movement issues? particularly using it in conjunction with a carbon rail saddle, lower clamping tolerances of the carbon rails are not adequate to hold the saddle position.

  13. #13
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    I got following reply from USE regarding the different clamps on their seatposts and usage of a Selle Italia SLR which was rocking forward / backward in the clamps when tightened to 12Nm :


    we make a range of clamp sizes and it sounds like the vertical height that you have is to great for the rail. We haven't measured the SLR saddles so if you can find the saddle rail dimensions then you can pick from the list below that we produce.

    SUMOCKBK
    7mm standard circular rail

    SUMOCKBK8.0
    8mm diameter circular rail

    SUMOCKBK9.2x7
    9.2mm high, 7mm wide oval rail

    SUMOCKBK9x7
    9mm high, 7mm wide oval rail

    SUMOCKBK9.7x7
    9.7mm high, 7mm wide oval rail

    SUMOCKBK9.8x8
    9.8mm high, 8mm wide oval rail

    SUMOCKBK10.3
    10.3mm high, 8mm wide oval rail

    SUMOCKBK9x8
    9mm high, 8mm wide oval rail


    Kind regards
    John
    USE

  14. #14
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    thanks mate, i have the correct clamp though, 9.7 x 7mm. the rails aren't slack in the clamp, it's a gradual repositioning of the seat angle whilst riding, relating to the tightness of clamp V's carbon railed saddle. i was wondering what people with this set up have/had issues?

  15. #15
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    Quote Originally Posted by parkincake
    if i may hijack the tread...

    does anyone with the USE 'save' seat post suffer with constant saddle angle movement issues? particularly using it in conjunction with a carbon rail saddle, lower clamping tolerances of the carbon rails are not adequate to hold the saddle position.
    i have a AX Ligthness Apollo saddle

    no issues

  16. #16
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    Quote Originally Posted by parkincake
    thanks mate, i have the correct clamp though, 9.7 x 7mm. the rails aren't slack in the clamp, it's a gradual repositioning of the seat angle whilst riding, relating to the tightness of clamp V's carbon railed saddle. i was wondering what people with this set up have/had issues?
    Have you tried carbon assembly paste between the rails and the clamp?

    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  17. #17
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    Quote Originally Posted by madskatingcow
    I got following reply from USE regarding the different clamps on their seatposts and usage of a Selle Italia SLR which was rocking forward / backward in the clamps when tightened to 12Nm :


    we make a range of clamp sizes and it sounds like the vertical height that you have is to great for the rail. We haven't measured the SLR saddles so if you can find the saddle rail dimensions then you can pick from the list below that we produce.

    SUMOCKBK
    7mm standard circular rail

    SUMOCKBK8.0
    8mm diameter circular rail

    SUMOCKBK9.2x7
    9.2mm high, 7mm wide oval rail

    SUMOCKBK9x7
    9mm high, 7mm wide oval rail

    SUMOCKBK9.7x7
    9.7mm high, 7mm wide oval rail

    SUMOCKBK9.8x8
    9.8mm high, 8mm wide oval rail

    SUMOCKBK10.3
    10.3mm high, 8mm wide oval rail

    SUMOCKBK9x8
    9mm high, 8mm wide oval rail


    Kind regards
    John
    USE
    My Scalpel came with a thompson post and the Fizik carbon railed saddle, I bought the carbon c'dale save post but looks like it came with clamps for a regular ti railed saddle, since the saddle won't fit at all. Would you know what clamps I'll need to make it work? Thanks.

  18. #18
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    the part of the clamp that pivots on the post is aluminium on aluminium so i doubt assembly paste would be all that useful, or it might be!?! USE recommend 10-12 Nm's for the clamp, however i'd imagine 10-12 Nm's would overwhelm the integrity of the carbon, would it not?

  19. #19
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    Quote Originally Posted by bikesinmud
    My Scalpel came with a thompson post and the Fizik carbon railed saddle, I bought the carbon c'dale save post but looks like it came with clamps for a regular ti railed saddle, since the saddle won't fit at all. Would you know what clamps I'll need to make it work? Thanks.
    9.7 x 7mm

  20. #20
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    Quote Originally Posted by parkincake
    9.7 x 7mm
    Thanks!!

  21. #21
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    Here is a picture of my clamp, the pin sticks out so little that I don't know that it makes much difference. I could slip it over the seat tube reversed without a problem.

  22. #22
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    My Flash 29er seatpost tightening have some problems.
    One is the low stiffness of the collar...
    Another is the stiffness of the frame that have a diameter a little bit greater than 27.2mm.
    In fact (without the grease), if you open the collar, the seatpost go down...
    ...and this is not good!

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