Need frame axle drop out mounting suggestions see pic

Discussion in 'General Questions' started by uncleargenius1, Dec 7, 2009.

  1. im running a bmp friction drive 1.25 freewheel roller and titan motor
    mounting to a 20" freestyle bmx frame judging from the attached pic am i good to just drill a hole through the axle mount bracket? will it hold?

    Attached Files:

  2. junme

    junme New Member

    looks like you got room for two if your want to be sure
  3. my other idea/option would be to cut my hollow axle some and tap thread the inside to allow it to be tightend right on/into the axle but tap threadings hard for me easy to f up
  4. ibdennyak

    ibdennyak Guest

    Yep. I am running a GXH50 with a belt drive held on with two 1/4 20 hardened bolts. No problems in over 8000 miles. From an engineering point of view, a 16d nail (like a soft #10 screw in cross section) is good for over 300 # in shear. (ie keep it tight) :grin5:
  5. update with install pics

    well i got it installed speed is 30-35mph with 1.25 roller take off is good i can accelerate without pedaling at a decent rate also went up some pretty steep hills engines super quiet titan 50cc four stroke cant hear it at idle i like stealthy because these bikes are a gray area in law cops not knowing the law might try to bust you even if your legal so when i see one i let off the gas and pedal and so far none have noticed me even when i go right past them on the rear frame i had to drill 7/32 and tap threads since a bolt even a slim one would have clearance issues with my freewheel also had to drill lower mounting holes since the kits more designed for bigger rims tires all in all im happy but now want to go bigger badder faster im thinking full suspension mid frame mounted chain driven gear changing pocket bike engine with liquid cooler radiater and belt water pump pushing 12hp:grin5:

    Attached Files:

  6. SimpleSimon

    SimpleSimon Active Member

    I realize the temptation, but be aware that NOWHERE would such a beast ever be legal - bicycle frames are NOT built to the standards even the most basic motorcycles must, by law, meet. What you are describing is a motorcycle, pedals or no pedals.

    Your built bike I quite like - nice job.
  7. spad4me

    spad4me Member

    A gp 460 will easily propel a motorized bicycle to speeds of 55 mph.
    They make about six hp at 15,000 rpm.
    The bicycles all too soon are destroyed.
    Been there done that.
    Not that much fun having a front flat at any speed over 40 mph .
    The cars do not expect you to be moving that fast and will pull directly in front of you.
    Not as much fun as I thought it would be.
    Now I ride at safer speeds, the reserve ability is nice though.

    Full suspension makes the bike wobble at speeds.
    Front suspension is nice though
  8. happycheapskate

    happycheapskate Active Member

    Try this:

    I don't think you should do that, but its your bike. You don't have much material there (on a critical part!)

    I think you should have someone weld on a little metal there, or make some kind of bracket that uses your axle bolt.
    BMX motorbicycles are cool! So far I've only seen people use them for roller drives, but I want to build one with a belt drive and edger motor or using a Grubee on a rear rack with a little BMX chainring made into a drive gear.

    Good luck!

  9. happycheapskate

    happycheapskate Active Member


    Here's a way to do it with no welding or anything drastic:

    Put the bracket behind the dropout and seat stay, and mount it through the dropout ear there. :detective: You have a lot of room to position it back there: sometimes this is how you have to mount rear racks.

    Use a quality bolt on each side such as a 6mm x 1.0 or 1/4" high grade hex head bolt and a "tension nut." Use a flat washer on each side of the dropout, and put the Tension Nut (or Nylock nut would also work) on the outside. Tighten them down. Now you can hacksaw off the end, leaving a little bit of threads for a Cap Nut (the kind with the round thing on the end, nice looking).