I thought I lost you somewhere back there, I have been wondering how you are proceding. It's nice to find someone else doing the friction thing too, when it seems so rarely executed.
So I was brainstorming on securing the tread to the tire and it all became obvious!!
1. Cut out tire to match the 3 speed hub.
Here is where it gets interesting...
2. a) Lace tennis racket string through spoke hole, into the sidewall of cut up tire, routed underneath tire tread contact patch, and out the other side to spoke hole, tension, and repeat 36 times.
b) Use long thin screws, to accomplish the same thing.
Will tennis string be strong enough? Will the flex be good or bad? Dumb idea