Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8
  1. #1
    rider of the east sherpaPeak's Avatar
    Join Date
    Oct 2005
    Posts
    722
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    other than that butt numbing crash.....

    how do you figure out if your frame has a crack or not....

    okay.......after last weekdends of trail riding my bike needed some cleaning...I finally go the time on wednesday night to take care of it...while I was sashing down the down tube I found a 3 inch hairline mark on the frame/tube. First I thought thought that it may be the mark on the decal...further investigation shows that its not the case......I can feel the hairline separation on in the tube (may be the paint or may be the frame itself).....

    now, how could I determine if its a crack or not? I know that I can take it to a local store etc.....I was wondering if there is an obvious way I can determine it before taking it to sewhere else...

    thanks for your help
    "....You are never lost, if you dont care where you are...."

  2. #2
    Senior Member
    Join Date
    Dec 2005
    Location
    southern oregon
    Posts
    2,631
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    a magnifying glass and a good light works well

  3. #3
    In search of moar cowbell dminor's Avatar
    Join Date
    Oct 2004
    Location
    The 509
    My Bikes
    1971 Suzuki TS125/ factory race kit/AHRMA-legal; 1969 Suzuki TS250/factory race kit; 1967 Suzuki K-15 Hillbilly Trail 80; 1977 Yamaha IT175; 1964 VanTech Scrambler racing frame
    Posts
    12,123
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    You may be able to 'ping' up and down the downtube (like with a knitting needle, chopstick or whatever you have on hand) and listen. There will be changes in tone from the butting in the tube, but once you get around the area of the suspected crack - - if it is a crack - - there will be a dead 'tick' instead of a 'ping.'

  4. #4
    rider of the east sherpaPeak's Avatar
    Join Date
    Oct 2005
    Posts
    722
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I did that......that was my first test.......but as I am not experienced, at least not with cracks......I can hear that there is a thicker ping at the middle of the tube where the suspected crack is...but I can not really be sure. now, if you strike on a tube with a metal the sound created by the either end would be different than the sound created by the middle.......so, the slightly thicker sound that I am hearing..is it the crack or is it just the physics of an hollow tube....

    dminor, thanks for your help........that is a wicked bear you have up there.....
    "....You are never lost, if you dont care where you are...."

  5. #5
    In search of moar cowbell dminor's Avatar
    Join Date
    Oct 2004
    Location
    The 509
    My Bikes
    1971 Suzuki TS125/ factory race kit/AHRMA-legal; 1969 Suzuki TS250/factory race kit; 1967 Suzuki K-15 Hillbilly Trail 80; 1977 Yamaha IT175; 1964 VanTech Scrambler racing frame
    Posts
    12,123
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Only way to know for sure, of course, would be dye penetrant testing (which, if you could find a lab, might cost more than the frame) - -it's like magnafluxing for non-ferrous metals.

    Short of that, you may have to scrape away enough paint and clean down to bare metal for a better visual inspection.

    The bear - - Friend of mine (actually my old mentor) - - an old-school illustrator and cartoonist - - did that caricature of me and the bear.

  6. #6
    unofficial roadie DirtPedalerB's Avatar
    Join Date
    Jul 2006
    Location
    Out in the woods you see
    My Bikes
    2004 Marin bobcat trail, 2006 trek fuel ex7, 2007 iron horse road bike
    Posts
    1,444
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    if it's right in the middle of the tube I'd keep riding it and watch and see if it expands.. usually the cracks are near the ends at the welds or maybe where the butting begins or ends.. more then likely it's a scratch..
    post a pic for all the experts here to overanalize.

  7. #7
    Senior Member wheelhot's Avatar
    Join Date
    Aug 2005
    Location
    Malaysia
    My Bikes
    Giant Anthem, Polygon Quatro
    Posts
    1,554
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    another way is to see if you cant stuck something thin (maybe like paper or thinner) into the crack and see if the paper went inside

  8. #8
    Commited Suicide WannaGetGood's Avatar
    Join Date
    Aug 2005
    Location
    Abbotsford.BC
    My Bikes
    2001 Kona Stuff & 2004 Rocky Mountain Switch SL
    Posts
    2,416
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Feel it.

Posting Permissions

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