Re: FRICTION DRIVE or CHAIN DRIVE-WHATS BEST
Friction drives are awesome for their simplicity and ease of mounting, but the darkside is a loss of efficiency and excessive tire wear.
The chain drives while a bit more work to mount properly are the most efficient, they also don't suffer from "slippage" should it be raining/snowing.
Personally - I prefer a mid-engine, in-frame, chain-drive as I think it the best of all (inc. weight and balance), while it's more of an effort to convert a bicycle - there's a reason motorcycles have their engine where they do
Having said that - I've had all of the above and each had advantages/disadvantages, every build is a compromise depending on what you want... and every last dang one of 'em was a blast to ride