Advertise on Bikeforums.net



User Tag List

Results 1 to 12 of 12
  1. #1
    Newbie
    Join Date
    Nov 2009
    Location
    Ft. Rucker, AL
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Cracked alum frame at rear seatpost entry

    Hello and thanks in advance. So my problem is this. I have a small crack in the rear of the frame where the seatpost would insert on my 2003 Cervelo Soloist (alum).

    I have been reading in this forum about TIG welding as an option but was curious to see what other thought was the best fix. The mechanic at my lbs told me this crack when fixed SHOULD be okay as it doesn't receive an overwhelming amount of stress. Is this accurate at all?

    Is this crack worth fixing? I am willing to pay to keep this frame in use if it that's the big factor. Thank you in advance.





    My apologies on the low quality pics.

  2. #2
    Guest
    Join Date
    Jul 2008
    Location
    Grid Reference, SK
    My Bikes
    I never learned to ride a bike. It is my deepest shame.
    Posts
    3,769
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Are you the original owner of the bike? Because I would certainly try to get it repaired or replaced under warranty.

    As for what your LBS mechanic said, it is possible that a repair will hold but it is impossible to tell for sure. Also, the weld will probably be either more or less brittle than the rest of the tube, and that spot needs some flexibility if you will ever be removing or replacing the seatpost.

    To recap, try to get it warrantied.

  3. #3
    Senior Member c.miller64's Avatar
    Join Date
    Jan 2009
    Location
    Tampa Fl
    My Bikes
    Cannondale Six13 Pro, Cannondale Slice
    Posts
    343
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Have it TIG welded, it should be fine.

  4. #4
    Senior Member
    Join Date
    Feb 2009
    Posts
    4,143
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    I would go for the warantee. Aluminum has a finite fatigue life. After so many million+ flexes it is going to crack. Check with Tenwheels. Fred's Felt cracked at the seatpost bottom bracket junction. Felt is giving him a new bike.
    Aluminum is weldable, but you shouldn't have overstressed it and took it past it's yield if it had proper thickness at that point. They should give you a new frame.

  5. #5
    Newbie
    Join Date
    Nov 2009
    Location
    Ft. Rucker, AL
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I bought the bike used so warranty is out of the question unfortunately. I hadn't considered the fact that the weld could effect removing the seat post, now I'm somewhat worried about the weld.

    For some additional history. I bought the bike used and the guys at his shop tightened down the seat post collar without the post in it, resulting in the crack he believes. He has offered a full refund or to pay for whatever it takes to fix it. I got the bike for 700$ and don't think I can find another deal like this so I'm very hesitant to return it and would like to fix it if at all possible (on his dime of course). Any other thoughts? Thank you for the responses thus far, much appreciated.
    Last edited by jk1199; 11-20-09 at 09:17 PM.

  6. #6
    Galveston County Texas 10 Wheels's Avatar
    Join Date
    Nov 2007
    Location
    In The Wind
    My Bikes
    GTO
    Posts
    25,846
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jk1199 View Post
    I bought the bike used so warranty is out of the question unfortunately. I hadn't considered the fact that the weld could effect removing the seat post, now I'm somewhat worried about the weld.
    It could also be cracking in another area on the bike.

    Last edited by 10 Wheels; 11-21-09 at 07:41 AM.
    [SIZE=1][B]What I like about Texas[/B]
    http://www.youtube.com/watch?v=PGukLuXzH1E

    Set F1re To The Ra1n ( NY Night Rain Ride)
    http://www.youtube.com/watch?v=W7jfcWEkSrI

  7. #7
    Single-serving poster electrik's Avatar
    Join Date
    Aug 2009
    Location
    Toronto, Canada
    Posts
    5,096
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jk1199 View Post
    I bought the bike used so warranty is out of the question unfortunately. I hadn't considered the fact that the weld could effect removing the seat post, now I'm somewhat worried about the weld.

    For some additional history. I bought the bike used and the guys at his shop tightened down the seat post collar without the post in it, resulting in the crack he believes. He has offered a full refund or to pay for whatever it takes to fix it. I got the bike for 700$ and don't think I can find another deal like this so I'm very hesitant to return it and would like to fix it if at all possible (on his dime of course). Any other thoughts? Thank you for the responses thus far, much appreciated.
    Well I may be wrong but i think that area of the bicycle is a low-stress area, so failure might not be catastrophic(i doubt your seat-stay and part of the seat-tube would shear off). It is a fairly large crack though and will continue to work it's way down the seat-tube, welding may stop it - maybe since there might be a stress fracture that runs down the seat-tube but is not visible to your eye.

  8. #8
    Senior Member
    Join Date
    Dec 2004
    Location
    Athens, Ohio
    My Bikes
    Custom Custom Custom
    Posts
    5,104
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Whats gonna happen is the crack is going to propagate around the welds on the seatstays. Unfortunately, I dont really think welding the crack is going to be a wise idea. The tube may also deform when re-welding and you might not be able to reinsert the seatpost. Not a big deal if the seatpost is round since you can put in a reamer, but you have an aero seatpost which will make post weld machining pretty hard.

    Also when taking close up pictures, use the macro function on your camera

  9. #9
    Senior Member
    Join Date
    Aug 2005
    Location
    Pittsburgh, PA
    My Bikes
    '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
    Posts
    26,130
    Mentioned
    12 Post(s)
    Tagged
    0 Thread(s)
    A temporary fix is to drill a small hole, say 3/16", at the bottom of the crack to stop it's progression.

  10. #10
    Senior Member
    Join Date
    Feb 2009
    Posts
    4,143
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    Get your money back. It is the safest thing at this point.
    Drilling a hole (a policeman) may or may not stop the crack from growing.

  11. #11
    FBoD Member at Large khatfull's Avatar
    Join Date
    Aug 2008
    Location
    Woodbury, MN
    Posts
    6,188
    Mentioned
    1 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by davidad View Post
    Get your money back. It is the safest thing at this point.
    Drilling a hole (a policeman) may or may not stop the crack from growing.
    Drilling holes at either end of a small crack, then riveting in an aluminum plate, has repaired MANY an aircraft, small and large. So long as the hole is big enough to completely remove stressed metal it should be fine for this application, no?

  12. #12
    Newbie
    Join Date
    Nov 2009
    Location
    Ft. Rucker, AL
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Well I have decided to return the frame so it's back to shopping. Please send me a message if anyone stumbles across a 56 Cervelo S1 for sale. Thank you all for you help again, it is most appreciated.

Posting Permissions

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