frame cracks

Discussion in 'Bicycle Repair' started by azbill, Jun 11, 2007.

  1. azbill

    azbill Active Member

    I was cleaning my bike today and found the frame is cracked !!! :x
    my seatpost tube is at a severe angle and it has cracked above and below downtube :shock: :shock:
    the cracks wrap all the way around the seat tube

    I dropped my seat all the way down hoping to re-inforce it a little

    my question is , if I weld the cracks, should I make some kind of wrap-around gusset to strengthen it ?
    I'm thinking wrapped around seat tube above downtube,and welded to downtube

    as of rt now I am off the road and very bummed :evil: :evil: :evil:

    I can't take a pic rt now cause the cam is in canada with vinnie
    but here is a pic showing where cracks are

  2. azbill

    azbill Active Member

    I may have to retire my chopper because of this ( I love this damn bike too!!!)
    I do have another haro v1 i can put motor on, but then I am rt back where i was in friggin january when I decided to sell that one to build the deviate

    man i am so pissed rt now :evil: :evil: :evil: :evil: :evil: :evil:
    i just had to vent
  3. cracks

    Hi AZkronic well Lemme tell you how Farmer John would fix your bike frame.
    1) clean all paint off the cracks
    2) carefully weld the cracks, with brass or aluminum shaft inside so seatpost will still work, and not be welded in
    3) make flat steel Gussets to re-inforce the tubes, these should run straight forward and backwards AFTER the tubes have been welded and the seatpost still works in the frame
    4) touch up the black paint
    5) commence to ride it like you just stole it,

  4. azbill

    azbill Active Member

    thanks Mike
    have already started sanding cracks
    will get welded soon I hope
    the seat tube is cracked vertically behind down tube, thats why I thought of a wrap-around gusset (just for extra steel there)
    was thinking a 'u' with open end facing tank, legs welded to downtube
  5. Torques

    Torques Guest

    I feel confident you can make it work.
  6. Egor

    Egor Guest

    You can weld up the cracks but I suspect it will crack sooner. Unfortunately each time you weld something you deteriorate the metal, the gussets will help. I have had a lot of trouble with Vibration, and it looks like you have your engine out there on a spring, if you can get a brace over to one of the head bolts, or another brace from the front engine mount! Good looking bike. Have fun, Dave
  7. spunout

    spunout Member

    crap, bill...that sux :x . i think your 'feet-falling-off-the-pegs'-vibration is the culprit. until you get that solved, this may just be the beginning of cracks (but we hope not). sorry man :cry:
  8. azbill

    azbill Active Member

    the vibration prob is from the sprocket flexing on back wheel
    5 rings flex too much
    (changed to a 44 tooth and after installin 5x to get it centered and true, I thought I was done)
    my next purchase will be a 24" wheel w/disc and freewheel, I plan on mounting sprocket to rotor

    this problem is because of the design of frame
    the seat tube is at almost 45 degrees
    this causes seat post and tube to take a sideways pressure when you sit on seat (the reason why I can't use a suspension seatpost)
    the seatpost caused the seatube to crack because of this
    the only thing that was keepin my butt off back wheel was about an 1/8" of steel
    most bikes , when you sit on seat, the weight is almost up n down
    this one its almost a lever
    I need to find a the longest 25.4 seatpost I can , so I can use it as more re-inforcement

    sorry for the rambling, but this is giving me a mass headache and pissing me off terribly
  9. locoWelder

    locoWelder Guest

    Its the angal of the seat post down tube that stoped me from buying one , AZ if you have a small welder and the time cut that darn thing out and put in a new one more vertical if you can

    sorry its so crude but I think you see what I mean

    or put 1 in vert as posible and lets build you a seat pan I think between iride and me we'ed make you a sick one off from that.... what cha think Dan?
  10. azbill

    azbill Active Member

    I was thinking a seat pan myself
    the angle is so severe, I think thats what was causing the seats to fail
    (broke 1 spring, totally lost another)
    gonna keep sanding and thinkin
  11. locoWelder

    locoWelder Guest

    if you got the cash to look at and his fat fender and seat.....the frender can be split about 1 1/2 inchs out of the center and welded back,

    the seat will ride right in that curve
  12. azbill

    azbill Active Member

    I'm back on the road !!!
    pulled motor and swapped it into my haro mountain bike
    what a difference after getting used to chopper
    will use it till I fix deviate
    man I was jonesing to ride afte 2 days haha

    think I'm gonna try to design a seat pan and support to take weight off seat tube
    also was worried I wouldn't make the lake run in 2 weeks
  13. srdavo

    srdavo Active Member

    good for you!! :D

    keep the ride alive!!
  14. azbill

    azbill Active Member

    thanks Dave :D :D :D
    I forgot how much lighter an aluminum bike is over the deviate

    (all I can think of is the old beach boys line 'if she had a set of wings, manI know she would fly' from the song 409)

    fast enough to scare the carp outta me anyhow
    :lol: :lol: :lol: :lol:
  15. JosephGarcia

    JosephGarcia Guest

    Any chance you can find a new chopper frame that supports weight better? and just reuse your rims, wheels, forks, and stuff? I mean the first crack shows a flawed design in the frame itself. I dont think any amount of repairs will make it as strong as it could be. but who am i to say it cant be done? give it a try =D

    post a pic of the bike your using in the meantime
  16. Beach Boys Greatest hits?

    "If she had a set of wings, man I know she could fly, "she's my little duece cuope you don't know what I got!"
    "She's got a competion clutch, with a four on the floor, yeah she purrs like a kitten till the lakepipes roar, and if that ain't enuf to make you flip your lid, well there's one more thing.....I got the pink slip daddy"

    hmmm they were the best of times? On old Jacobs "woodie" a balsa wood surfboard, 8' 2", and the surf in San Diego never looked better......Mike
  17. acoop101

    acoop101 Guest

    to fix a steel frame weld on some extra plate to reinforce around the cracks. Welds generally don't crack unless they are improperlly reinforced. so add some. Speedy metals is a good place if you don't have a local metal supply house. What type of welder are you going to use? I would recomend TIG because of it's strength.:grin:
  18. turbo/chaos

    turbo/chaos Guest

    yeah frame craks are bad these is what i got in return for it

    my city pounder has died but the new one is being built for death race

    just take a look

    Attached Files:

  19. azbill

    azbill Active Member

    that bike, alas, is sitting stripped of all its good parts and will probably never see pavement again :(
    but, the parts from it are now in a schwinn jaguar that i will be posting pics of soon :)
  20. dbigkahunna

    dbigkahunna Guest

    One of the issues is the steel the tube is made form if it is 1-1/2 cr and you weld it with standard buz box rod, then it will crack again in short order. Take a magnifying glass and find the end of the crack. Drill a small hole at each end. If you miss by a little bit, you wont put this on the moon so dont worry. There are two process you can use. TIG or braze it. If you tig the crack, take a dremell and open the crack up with the small grinding disk. Be sure the paint is removed from the weld area. Warm the steel up by using a propane torch. Do not use a cutting torch with acetylene. This can affect 1 1/4 cr steel. After the repair area is warmed up, 200 to 250 degrees is you want to be specific, weld up the crack being sure to fill the holes at the end of the crack. Let it cool for 10-15 minutes and add another pass on top and extending 1/2 inch past the holes. Let it cool and then check the end of the weld with a magnifying glass to be sure the crack has not returned. Do not overweld this thinking more is better. The cap should not be any higher than the thickness of the tube. Try to keep the weld small.
    If you are going to braze the crack, again, drill stress holes at the end of the crack. Flux the crack area and butter with brass rod. After the crack is buttered, braze a bead over the crack. Again limit the height of the reinforcing material. Again extend 1/2 inch pass the stress holes. If you have the skills or know a BFG welder who knows how to put a bead down with brass, I would recommend brazing instead of TIG. But if you know a jam up TIG welder they can fix this problem.