Re: I am not competing just posting
If I didn't already have the scooter rear wheel with sprocket, i would have gone with the goped engine and wheel myself I think. I am convinced friction drive is less trouble than the chain wheel puller.
I have tried the chain friction wheel with electric which is about the same rpm and it works just fine. I am expecting my weedeater conversion to work easily. If not I might look for a different drive mechanism. With friction drive the engine can be less powerful since it doesn't have the dead weight of the bike to pull around. If it gets too much the wheel just skips over the bike wheel.
the other alternative is the smaller Izip rear wheel with the belt drive to just attach the belt drive pulley to the weed eater (in my case).
My posts have entertainment value only. A bike ain't yours till it has your blood on it. Then it owns you.