broken frame

Discussion in '2-Stroke Engines' started by ldad1ad2, Apr 12, 2014.

  1. ldad1ad2

    ldad1ad2 New Member

    the frame on my bike snapped on both sides in the back while riding. What caused that? Scared the hell out of me. I don't think these are safe. Will not ride aain.
     

  2. BigBlue

    BigBlue Active Member

    Pictures? Sounds like your frame had issues before you motorized. Rust and corrosion are bad signs. Stamped and pressed chainstays (Huffy) are another disaster waiting to happen. If it was aluminum, some members have had problems. Been in this hobby for 10 years and most members never have problems with frames. It is important to do a once over on your bike before taking off.

    Chris
    AKA: BigBlue
     
  3. HeadSmess

    HeadSmess Well-Known Member

    "frame snapped both sides at back"

    im assuming the seat stays have broken.

    you chose the wrong type of frame. a light weight racer type where theyre simply brazed to the sides. possibly. simply assuming. seen them break before, hard pressed to break any other type so far.


    lesson learnt. inspect frames and pick the one that looks strongest, not cleanest or neatest or a shiniest paintjob.
     
  4. wheelbender6

    wheelbender6 Well-Known Member

    Sometimes you just get a bad frame that had flaws. Newer discount frames are not as strong as pre-2000 frames. Avoid the frames where the rear cargo rack is welded on. They look clean but the heat of welding weakens the seat stays.
     
  5. jaguar

    jaguar Well-Known Member

    maybe you ride crappy streets with ditches
    maybe you are too damn fat
    maybe it is an old frame with rust inside the tube
    maybe you never did anything to lessen engine vibration and it was vibrating like crazy which weakened the frame and finally broke it
     
  6. 074KU

    074KU Member

    I agree.
    The 2 reasons that made my steel frame crack at the top of the down tube, that and no suspension forks on my first bike. Mostly the rubbish streets..
    Our streets degrade to the point of rider throwing, car rim smashing potholes then get patched 'till the road is made of patches. That being said it took our roads 5 years to crack the down tube..
     
  7. Fabian

    Fabian Well-Known Member

  8. butterbean

    butterbean Well-Known Member

    I'm gonna have to disagree with the portion of the argument about the rider being overweight. A weak frame is a weak frame, regardless of weight. Perhaps a heavier rider will cause a weak frame to break more quickly, but the problem is still the weak frame. I weigh around 275 (here come the fat jokes, no I don't care if you don't like my weight and calling me fat won't answer the OP's question so move on already) and I have NEVER broken a frame, motorized or otherwise. My first two motorized bikes were built on department store bikes and the first one did crack, but I wasn't riding it and the motor mounts had come loose and the motor was vibrating violently in the frame. I believe that's what broke that frame. I had given it to a friend who did not maintain it as well as I did. My second frame still sits in my basement till I figure out what to do with it or get rid of it. The frame I'm riding now is a repop schwinn cruiser with quarter inch thick walled tubing. The bottom line is that a strong frame will carry a heavy rider without issue, and who cares if someone is overweight? It's perfectly logical to assume that an overweight person might get offended by the word fat, and it's an ugly, hateful word. No, I won't lose weight for you. I should not have to change for other people to accept me. I should not have to lose weight so people won't call me fat. It's my body and my choice. I'm not trying to pick a fight, but if you have the right to judge me, then why don't I have the right to defend myself? Fat is another word that hateful people invented, and using it to describe another person makes you hateful too. It's no different than being racist. Fat, h.o.m.o, the "N" word, white trash, hick, redneck, they are all the same.
     
  9. IbedaYank

    IbedaYank Member

    he made 1 post and this was it. let it die as he will not be back
     
  10. Fabian

    Fabian Well-Known Member

    Maybe he is busy researching bikes that have good quality frames.
     
  11. Fabian

    Fabian Well-Known Member

    Maybe he is busy upgrading his life insurance.
     
  12. LR Jerry

    LR Jerry Well-Known Member

    Are you planning to repair the frame or replace it? If its repair it then what is the frame made out of? Can you weld? Do you have access to a welder and what kind? Otherwise take your bike to a welding shop. Where the stays connect to the wheel dropouts fill in the weight reduction cut outs. Where the seat and chain stays meet at the wheel dropout you may want to cut a piece of flat bar to fit and be welded in there to reinforce the area.
     
  13. LR Jerry

    LR Jerry Well-Known Member

    http://motorbicycling.com/album.php?albumid=1168&pictureid=9442

    http://motorbicycling.com/album.php?albumid=1168&pictureid=9441



    Are you planning to repair the frame or replace it? If its repair it the
    what is the frame made out of? Can you weld? Do you have access to a welder and what kind? Otherwise take your bike to a welding shop. Where the stays connect to the wheel dropouts fill in the weight reduction cut outs. Where the seat and chain stays meet at the wheel dropout you may want to cut a piece of flat bar to fit in there to reinforce the area. The first picture shows how I fixed a broken chain stay the second picture shows what it originally looked like.
     
    Last edited: Apr 16, 2014
  14. BigBlue

    BigBlue Active Member

    I think he's one of those one post members. Really no interest in becoming active in the community.

    Chris
    AKA: BigBlue
     
  15. IbedaYank

    IbedaYank Member

    Risk you take when using something outside of what it was designed for. There is a reason why motorcycle frames use bigger and thicker tubing.
     
  16. 074KU

    074KU Member

    Some of the old Matchless bikes from the 50s had tubing not that dissimilar from bicycles.
     
  17. IbedaYank

    IbedaYank Member

    Bamford-AMC-Frame.jpg

    yep sure looks like a bicycle frame... now if your talking about one of many that used a 98cc 2speed sachs you would not be far off the mark but not a Matchless frame.
     
  18. IbedaYank

    IbedaYank Member

    tubing used on even a 98cc 2speed Sachs German made Wanderer .. Russian made Dnepr Kievlanin was 24.015mm X 2mm thick tube. The tubing used for a
    single or twin cylinder was even much larger/thicker. Most bicycle tubing is .5 or .8mm the thickest is 1.5mm that is used for bottom bracket shells and headtubes.
     
  19. HeadSmess

    HeadSmess Well-Known Member

    some of the modern motorcycles still for sale at dealerships new and rolling out of factories are the same as whats used in bicycles... its usually not the steel itself, but the joins. or any heat affected areas. i have had a haro frame do a strange sort of spiral crack down the top tube, starting a few inches from the headtube...


    on that note, ive seen lengths of 19mm bar get turned into drifts, only to find the bar had a crack running the entire length, that was only revealed when heated up redhot for the final stage, hardening the points. hi quality heat treating bar from a reputable supplier. it does happen.
     
  20. IbedaYank

    IbedaYank Member

    29er frame tube set..
    http://www.cycle-frames.com/bicycle-frame-tubing/29er-Tubeset-35-X-969-DT.html

    thickest tubing 1.2mm

    http://www.jpcycles.com/product/701-510
    aftermarket Harley Davidsodson softtail frame 1.250 x >120 wall = 3.048 mm

    that is at times more then 3X as thick as bicycle tubing and double that as there are TWO down tubes not just one and most HD motors have a top motormount besides the lower mounts and transmission mounts that tie everything togather to make it a more solid unit as compared to a chinadoll only using two mounts.. .. Now that the FACTS are right here tell me again how the tubing is the same???
     
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