Page 1 of 2 12 LastLast
Results 1 to 15 of 19
  1. #1
    Git yer dumb questions here Spunger's Avatar
    Join Date
    Feb 2003
    Location
    805
    Posts
    2,262
    Rep Power
    6

    How to tell if my frame's cracked?

    Well.........I think it happened......won't say what brand so don't ask, but how can you tell if you're frame's cracked? Today while changing out a bearing on a linkage I noticed some small cracks in the powder coat around the seat-tube area welds and the shock mount. I was like........F*$&*#$ because the powdercoat is clearly cracked. I'm assuming it's a crack but not 100% sure. What really pissed me off was a crack as well on the rear chainstay. So I knew my 2 year old frame now bit the dust.

    What really shocks me is I've done no drops, no jumps, nada of that sort (I have other bikes built for that stuff) and this was simply a trail rig. Nothing but riding to the trail and down it (mostly XC'ish stuff) so when I found these possible cracks I got worried.

    Do cracks in the powdercoat usually mean a crack in the material? What places can you ride with a crack and without one? In my case of a shock mount and the seat-post mount (which is a interupted seat tube) I don't think that these cracks I can ride with. Hell I could be riding climbing a hill sitting and have it just give away. Same with the shock.

    Just curious, I've read alot about cracked frames and such but can't find too much info on the symptoms of a cracked frame or what to look out for and watch for.

  2. Advertisement - Log in or Register to hide this ad
  3. #2
    Turbo Monkey
    Join Date
    Nov 2001
    Location
    Sydney, Australia
    Posts
    1,086
    Rep Power
    7
    Get a sharp knife and flake back the powdercoating around that area. Don't sand/file the paint away as you'll obscure any cracks, make sure you flake it away. You may be able to use a dye/paint, drip it on the area and wipe it off to see if there's a crack.

  4. #3
    Turbo Monkey vitox's Avatar
    Join Date
    Sep 2001
    Location
    Santiago du Chili
    Posts
    2,940
    Rep Power
    7
    Quote Originally Posted by Spunger

    Just curious, I've read alot about cracked frames and such but can't find too much info on the symptoms of a cracked frame or what to look out for and watch for.
    well if the paint is cracked in a pattern that you would tend to think of as a place where the frame could eventually fail, or where other frames crack, you really should at least take the paint off and have closer look, ideally, take it to someone knowledgeable or that has cracked frames before.
    y que tanto mirai vo?

  5. #4
    My name is Nick Nick's Avatar
    Join Date
    Sep 2001
    Location
    Stoked.
    Posts
    6,460
    Rep Power
    11
    remove the seatpost and fill the frame with water.
    hold the bike up in the air and watch for leaks.

    you're welcome!

    "What places can you ride with a crack and without one?"
    None safely, at least not for long.

    just kidding about the water ... I hope you frame isn't really cracked. I guess the only way to know for sure is to chip away the p.c. and inspect the metal.
    Last edited by Nick; 07-05-2006 at 08:49 AM.

  6. #5
    Monkey konabiker's Avatar
    Join Date
    Jun 2004
    Location
    Santa Barbara
    Posts
    669
    Rep Power
    6
    Is it an older cortina?

    That will pretty much answer the question.

  7. #6
    Git yer dumb questions here Spunger's Avatar
    Join Date
    Feb 2003
    Location
    805
    Posts
    2,262
    Rep Power
    6
    Quote Originally Posted by konabiker
    Is it an older cortina?

    That will pretty much answer the question.
    Nope, I'm not gonna bash/praise any manufacture until the end :hot:

    I've made a few calls and emails, just waiting for a response. I guess either way, a stress mark where it cracks the powdercoat is no good, and in the area's that it decided to crack are areas in which I'm not going to go for.

    I'll see about chipping away the powder coat in the areas where the cracks are.

  8. #7
    Turbo Monkey Kornphlake's Avatar
    Join Date
    Oct 2002
    Location
    Portland, OR
    Posts
    2,639
    Rep Power
    6
    It doesn't really matter if it's just the powdercoat that's cracked or the metal, if the finish is starting to wrinkle or crack it means the tubes have either cracked themselves or stretched/bent in some way. Either way your frame isn't safe to ride. Unless the bike is steel I'd say don't ride it on anything. I'm sure you've seen just as many stories about the guy who rode off a curb and his headtube ripped off as I have. Fatigue failures can happen at any time, there isn't really any way to estimate how long until catastrophic failure once you've seen signs of fatigue.
    ¿Entonces Ya?

    Hooray I'm a movie star!
    Taco Eater Patrol
    Urban Wussies

  9. #8
    Git yer dumb questions here Spunger's Avatar
    Join Date
    Feb 2003
    Location
    805
    Posts
    2,262
    Rep Power
    6
    Quote Originally Posted by Kornphlake
    It doesn't really matter if it's just the powdercoat that's cracked or the metal, if the finish is starting to wrinkle or crack it means the tubes have either cracked themselves or stretched/bent in some way. Either way your frame isn't safe to ride. Unless the bike is steel I'd say don't ride it on anything. I'm sure you've seen just as many stories about the guy who rode off a curb and his headtube ripped off as I have. Fatigue failures can happen at any time, there isn't really any way to estimate how long until catastrophic failure once you've seen signs of fatigue.
    That is what I was looking for. I have heard those stories, and I don't want to be one of them (instead of head tube seat tube). I figured that the powder coat cracked because of something, weather it be a stretch, crack, stress mark whatever. I won't take my chances.

    Nope, it's not steel. At times I wish it was because I know if this happened it'd be a quick fix (just re-weld it) but being alum. it's not that easy. It just sucked because usually you don't find these "cracks" on both the front triangle and rear triangle. That was the real bummer because I could have salvaged the frame if only one part was cracked, but not both.

  10. #9
    Git yer dumb questions here Spunger's Avatar
    Join Date
    Feb 2003
    Location
    805
    Posts
    2,262
    Rep Power
    6
    Well it's cracked, I chipped away some of the powder coat and sure enough it's cracked.

    To repair the frame it'd cost $400-450 and that's on a 4 year old frame. So it might be time for something new'er than that.

    Oh well, thanks again guys for the hints and tips on making sure it's cracked. I just think the frame saw better days, atleast it didn't crack and fail so bad that I couldn't keep riding it out of the trail.

  11. #10
    Celebrating No-Pants Day kidwoo's Avatar
    Join Date
    Aug 2003
    Location
    In my pants
    Posts
    16,739
    Rep Power
    15
    Well it IS an m1 you know.

    You got the seat tube though? That's a new one.

    4 years on any dh frame is a good run.

    Sorry to hear about it.
    STRAVA: Turn your dork logger off when you're on unsanctioned trails numbnuts

    Switchacks = woodland based crimes against humanity

  12. #11
    Git yer dumb questions here Spunger's Avatar
    Join Date
    Feb 2003
    Location
    805
    Posts
    2,262
    Rep Power
    6
    Quote Originally Posted by kidwoo
    Well it IS an m1 you know.
    4 years on any dh frame is a good run.
    I think that's how I have to look at it, 4 years on any alum. frame is a good time span. Even though I would have liked it to have lasted longer I guess it's ok.

    I guess it's time to save for something else

  13. #12
    Turbo Monkey WestCoastHucker's Avatar
    Join Date
    Oct 2003
    Location
    daydreaming about a new rhythm line.....
    Posts
    2,512
    Rep Power
    7
    why did you feel the need to jive us with your "2 year old" frame nonsense, then come back to tell us it was over 4 years old?

  14. #13
    Monkey LaharDesign's Avatar
    Join Date
    Jun 2006
    Posts
    159
    Rep Power
    5
    Look people shouldn't be too shy about welding up a cracked alloy frame.
    Very few aluminium frames are heat treated after welding these days and if its a 7000 series its Impractical to do that and so never done.
    whatever your frames made of just clean the powdercoat off for an inch around the cracks, file a v groove where and past the ends of the cracks and have someone tig weld them up. Ask for a nice smooth fillet with low temp silicon alloy rod and you'll get a better result than new. Other places may develop cracks so its not quite like new.
    funs for forever

  15. #14
    Celebrating No-Pants Day kidwoo's Avatar
    Join Date
    Aug 2003
    Location
    In my pants
    Posts
    16,739
    Rep Power
    15
    Quote Originally Posted by LaharDesign
    Very few aluminium frames are heat treated after welding these days

    What?

    Like EVERY 6000 series aluminum frame.......which there are a lot of.....including intense don't get heat treated?

    Sure a few use 7000 series but just as many or more use 6061. And 6061 is REALLY fun to ride without a heat treat.
    STRAVA: Turn your dork logger off when you're on unsanctioned trails numbnuts

    Switchacks = woodland based crimes against humanity

  16. #15
    Monkey LaharDesign's Avatar
    Join Date
    Jun 2006
    Posts
    159
    Rep Power
    5
    full cred to boutique companies that do heat treat after welding.
    Its still worth welding these frames up if they crack outside warrantee.
    funs for forever

Similar Threads

  1. Cracked frame C.S. info
    By Kntr in forum Downhill & Freeride
    Replies: 28
    Last Post: 10-27-2005, 12:58 AM
  2. Azonic frames?
    By trailhacker in forum Downhill & Freeride
    Replies: 1
    Last Post: 03-08-2005, 07:14 PM

Bookmarks

Posting Permissions

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