Tire shredding?!

Discussion in 'Friction Drive' started by Trip, Oct 14, 2010.

  1. Trip

    Trip New Member

    Just finished my first motoredbike build. It's a BMP friction drive with a Monster Scooter Parts 52cc Chinese engine. Took it out for its first test drive yesterday, had a blast. Got home, looked at the bike, and the rear wheel and the chainstay were covered in black dust. Turned out to be rubber!

    Keeping in mind that I'm a complete beginner at this stuff, what do you folks think I'm doing wrong? I figure I might have too much downward pressure on the roller, too little air pressure in the tire, or just incorrect riding skills. Maybe all of the above!

    Any and all input is appreciated.

  2. Alaskavan

    Alaskavan Guest

    Some tire wear is normal with a friction drive. What tire are you using? A knobby will wear out faster than a smooth tire. Under-inflation of the tire will also increase tire wear.
  3. srdavo

    srdavo Active Member

    Take off gently..... pedal to get yourself rolling and gradually increase the throttle.

    Jack-rabbit starts will cause the drive roller to spin on the tire.
  4. Trip

    Trip New Member

    Tire trauma

    Thanks guys! I have a Kenda beach cruiser tire, so it's pretty wide and smooth. However, I never even checked the pressure other than squeezing the sidewalls, and I might have done a few jackrabbit starts and experimentally over-revved a few times. Hopefully that's the cause of the rubber dandruff. Being a "glass half empty" kind of guy I figured I had FUBARed the whole installation and tragedy and destruction were in my immediate future. Hard to believe a middle-aged man can work up that much angst over a bicycle...
  5. loquin

    loquin Active Member

    A few points:

    • Make SURE the roller is perpendicular to the tire. It should be at 90 degrees, and this is especially critical when looking down from above. If the roller is at an angle, it acts a little like a spiral router bit, grinding away at the rubber with every roller rotation. It's not as critical that the roller be exactly level, but, if it's not, you'll get some additional wear, as the roller contacts the tire at different radii from the axle... meaning that a point on the tire in contact with the roller at one edge travels slightly farther than a point on the other edge, relative to the roller, with each tire rotation.
    • Keep your tire pressure up - a firmer tire allows you to apply more pressure with the roller. I normally run at 50 psi on Continental Town & Country tires.
    • ALL other things being equal, a slick tire gives you the best traction, least wear, and smoothest ride on pavement, under all conditions (except, possibly, wet snow.)
      [Your roller should press 'into' the tire at least a quarter of an inch and, depending on tire pressure and road/roller slippage conditions, sometimes even more.
    • And, as others have said, avoid jackrabbit starts, and feather the throttle when it's wet.

    ref the FD FAQ
    Last edited: Oct 14, 2010
  6. adb140275

    adb140275 Member

    i get a TINY bit of rubber... nothing much. 55psi on cheng shin c1218 tires. you might not have the roller on firm enough, causing slip, which will shred....