New Friction Drive Build -featherlite 25cc

Discussion in 'Friction Drive' started by Tinker, Nov 15, 2009.

  1. Tinker

    Tinker New Member

    Hi all, here are a few pics of my first and only friction drive build. It's a Weed Eater Featherlite 25cc on a Target aluminum frame mountain bike. Enjoy.


    Attached Files:

  2. cpuaid

    cpuaid Member

    very nice build, looks fairly easy to fabricate using common components. what size roller and where did you get it from? what type of performance are you getting with it? (speed, mileage)
  3. Will Snow

    Will Snow Member

    neat creation

    You built the whole mount yourself I take it. Good for you, that is the kind of thing I like to see.

    I also would like to learn how it is doing for you.
  4. Mountainman

    Mountainman Active Member

    looks like direct drive ??

    ride that thing
  5. Tinker

    Tinker New Member

    Thanks all. I fabbed everything myself. Yep, it's direct drive. Bump start. I simply push the wooden handle down to engage and lift up to disengage. I use a leather strap to secure it when idling so it doesn't slip "into gear". It works quite well.

    I fabricated the spindle from 1" aluminum stock, drilled and tapped it to bolt onto the flywheel. I then (using a suggestion found here) JB welded emery cloth to the spindle for friction. The lefthand bracket is angled aluminum, the righthand bracket is a steel bar and the center bracet it steel strapping.

    I don't know how fast it goes but I'd estimate 15mph. I don't notice the weight of the motor at all (I'm guessing it's 7lbs with fuel).

    I've only put a few miles on it so far...noisey and fun.
  6. Mountainman

    Mountainman Active Member

    nice Tinker -- neat and simple

    nice Tinker -- neat and simple
    works for me regarding bikes and the Ladies

    ride those THINGS
  7. Will Snow

    Will Snow Member

    I thought I would check back with you now that you may of had time to use your friction drive.

    How is the the JB Weld roller holding up and tire wear? I like your simple, "BUILD IT YOURSELF" approach.
  8. Tinker

    Tinker New Member

    Thanks. The JB Weld is holding up extremely well but the tire (Target special) seems to be wearing out rather quickly. But I haven't been riding it much since the 20" snowfall a couple of weeks ago.
  9. Will Snow

    Will Snow Member

    20" of snow, that would make it tough to ride in alright. the sand paper roller would probably do well in wet weather though.

    I Remembered something while thinking of your friction drive. I had a little friction drive a few years ago that I really liked, called a MX-5. It is no longer available but the drive roller is what I want to tell you about. The roller had several groves cut across the width of the roller and they were not that deep. What I think is good about this is, just about anyone could make the groves with a metal cutting saw or even a 3 cornered file. This roller was made of steel and seemed to last forever.

    With your idea and these two types of rollers: Most do it yourself people could put this together with simple tools and very little cost. Rain or shine a person could have simple, inexspensive and reliable transportation.

    What do you think?
  10. Esteban

    Esteban Active Member

    I remember the MX-5 kits. I think they were from S. Korea. I really liked the way they were mounted.
  11. You will do better with a smooth "street" treaded tire, especially in the center of the tread where it is in contact with the roller. Nice build. The only trouble I've had with my friction drive bike is with the rear wheel. Since we travel at greater speeds than pedaling alone, I've broken some spokes, knocked the rear wheel out of true, and bent a rim hitting bumps. You may need a much heavier duty rear wheel over time.
  12. velosolex

    velosolex Member

    Nice looking build! I've been doing friction drive builds since 1972, and have found urethane (medium durometer) to be a great friction material for riding in dry weather. The urethane can be purchased in rod form, drilled out and pressed onto a steel or aluminium "mandrel" that can be knurled before pressing so the urethane will not slip. Over time, the urethane will wear slightly and offer better surface contact with your tire. Urethane will not work on wet streets! Carry an aggregate lined roller for wet weather and switch out as required. I've run rollers as small as 7/8 OD on small weed wacker engines, and as large as 1-1/4 OD on 49cc, 2 HP 2 strokes. If you run a big engine, find yourself a Solex friction roller on eBay or contact Velocruz up in SLC, Utah and they will sell you one. You'll have to fashion a mandrel for the roller, but they work better than anything else I've ever used. They have to pressed hard against the tire, but tire wear will be much better than what you are experiencing. Your current emery cloth roller will sand your tire to death in short order (ask me how I know) :whistling:
    Nice thing about your small engine is you can build yourself a quiet exhaust and go riding without anyone hearing you. I've used engines as small as 21cc's.

  13. tom80

    tom80 New Member

    I have a go-ped motor 23cc on my friction drive mb. I have found the black magic roller to work very well in wet weather.
  14. velosolex

    velosolex Member

    If it works for you, thats great!! Let others know where you bought it from and maybe give details as to cost and your buying experience(s). Perhaps you can give us a detailed source for this drive component?

  15. tom80

    tom80 New Member

    I bought this spindle from ddm and it is used for a go-ped. The spindle has 1 mm deep channels cut in it all the way around and is heat treated. Spindle size range from .625 - .950 and cost about $21.00. I used the .750 spindle when my motor was stock and could keep a steady 25 mph and light peddling to maintain 25 mph up hill. I also tried the .950 spindle and could hit 27 mph but acceleration was lost. I weigh almost 200 and it would still climb most hills and the sound level was way down. They also sell a ADA racing 54 mm clutch kit made to drive this type of spindle for around $75.00. My 23 cc motor made 2.0 hp stock and about 1.0 ft lbs. I bought all my parts from ddm and have got great service and the tech line will help to insure parts are compatible. ddm mainly sells go-ped, pocket bike and rc car parts.
    Last edited: Jan 28, 2010
  16. velosolex

    velosolex Member

    How well is your tire holding up with the spindle(s) your using? I don't know how goped tires compare against bicycle tires regarding number of plys, thickness of rubber on tire and durometer of rubber compound. Note tire diameter of goped tire is much less when compared to 26" bike tire meaning that ratio of spindle to tire diameter is much different when comparing both applications.

  17. tom80

    tom80 New Member

    I have the tire set at 90 psi and is a 1.5 slick. I did not even consider the number of plys or hardness of rubber. I will look into it. So far my tire is holding up great. Probably got lucky. Thanks for the info. I am not understanding the spindle to tire ratio. When I do the math using same .750 spindle top speed for both bike and scooter are the same. In real life the scooter will probably be faster due to tire hardness. Please let me know what you mean.
  18. velosolex

    velosolex Member

    I was wrong about the tire diameter coming into play with friction drive. Actually tire diameter will have no impact. The way it all works is just as if the friction roller were running along the ground. All the tire does is act as a go between the roller and the pavement :idea: . It's been a while since I've done the calculations but here's how I figure it:
    There are 63,360 inches in one mile
    Your roller diameter is .75" x 3.141 = 2.36" in circumference
    Your roller must turn 26,847 times to go one mile
    Say your engine is turning 5,000 rpm for one mile, it will take 5.4 minutes @ 5,000 rpm to go one mile. Last 60 mph / 5.4 minutes = 11.1 mph travel speed

  19. loquin

    loquin Active Member


    Speed = RPM * D / 336.14

    where speed is in MPH and D is roller diameter is in inches.
  20. velosolex

    velosolex Member

    Very good simplification :idea: