My friction build (attempted)

globalenigma · Mar 23, 2009

Here is my attempt at a friction drive system. I know there are a few problems but I am trying to work those out. If you can see any room for improvement let me know ( i know there is plenty). Well here are my pics.

srdavo · Mar 23, 2009

the small diameter friction roller ought to have good low-end torque.
questions....

what brand of engine?
how many cc's?
Is there a gearbox attached to the engine?

is there some sort of bearing, on the outer side of the friction roller?

I dig friction drives....tell me more!!

globalenigma · Mar 23, 2009

A little revision

I made some modifications. The roller was just slipping too much. The roller still needs some mods but this is much better now. Also not shown in the pics I added a bungee cord to hold it down on the tire a little. I think it works much better. I am looking into putting a disengagement system and some permanent springs on the read to hold down the roller when engaged.

5-7HEAVEN · Mar 23, 2009

Good job, globalenigma...

However, the engine should be mounted on the other part of the frame that swings with the tire.

What diameter is the friction roller?

You get better results with a street tire.

globalenigma · Mar 23, 2009

Questions Answered

Engine:

WeedEater --> FeatherLite LE
Size --> 33cc

(hey it was picked up down the road, neighbors were throwing it out.)
Yes there is a bearing on the right side.
No gearbox... yet

When tested it got me to 17mph at about half throttle. Only problem is after half throttle it just spins freely even with the new bungee

I feel like I cant get all the power to the wheel.

globalenigma · Mar 23, 2009

Good job, globalenigma...

However, the engine should be mounted on the other part of the frame that swings with the tire.

What diameter is the friction roller?

You get better results with a street tire.

Thanks for the support and advice but I can not understand what you mean about mount the motor on the frame that moves with the tire? (Both the right and the left sides move up and down together... please explain more)

So a street tire will help me out? I need to look into that.. Thanks for the heads up

5-7HEAVEN · Mar 23, 2009

globalenigma said:
When tested it got me to 17mph at about half throttle. Only problem is after half throttle it just spins freely even with the new bungee

I feel like I cant get all the power to the wheel.

You need to lock down the roller to the tire.

Some do it with springs or bungee cords.

Staton does it by locking the engine assembly to the rear axle, via long support struts.

I did mine with a lever to lock the assembly firmly onto the tire.

NOTHING will work well until you mount the engine assembly onto the bike's swingarm.

If you don't, the wheel's movement will break the roller or its attachments.

This is a dual-suspension bike. The rear suspension moves independently of the main frame.

If you were to disconnect the rear suspension strut, you will see how the engine will not be in contact with the tire at all times.

Nuttsy · Mar 23, 2009

Yeah,
I would agree on the tire. Although, your center tread where the roller contacts seems semi-tame.
The trick with friction drive is the tension between the roller and the tire. Bungy seems too light to me. Either find a way to LOCK the roller down mechanically (nuts and bolts) or heavy springs.
The roller seems a little on the small side. But, I don't know your terrain or the weight you're pushing. It may be right for you. Some more GRIP on the roller would help too. On homebuilts, some here advocate a JB Weld and sand recipe to help the roller grip better and stop the slip.
Hang in there and search the forum...lots of answers here.
You're off to a great start!
WC

globalenigma · Mar 23, 2009

Allright 5-7 HEAVEN, I understand you now. That is something I will have to fix... Things are starting to make sense now. That is one reason I did not weld to the bike frame yet, I wanted to make sure I could remove it at any time (for movement to another bike) or to just remove it an mod it like you are saying. That will have to come soon, I don't have time during the week to work on that. I am glad i posted now.

5-7HEAVEN · Mar 23, 2009

You can do it.

You are so close.

My friction build (attempted)

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