Heres a spoiler setup for ya. Double belt gear deduction. The thing with the spoiler is you have all kinds of room, the frame is set up wide open, you have no brake problems (front and rear disk) and the frame is heavy and solid as a rock. I have a nylon sheave bolted to the rim (no broken spokes that way). if you use a sprocket you need to set it up so the sprocket is also your brake rotor or you will have no back brake. If you can go without friction drive it would be way better.

Here is an early pic of the drive (stage 1) and a few recent pics done

__________________
What if all the rulers are wrong?