ive grown up riding bikes... for fun, professionally, and in competition.
cannabis is hands down the best "drug" to use while riding a bike... it will enhance the ride just enough and wont impair you, so you wont kill yourself...
ive found with ethanol there is a limit to safe riding....obv... 1 to 3 beers i can still ride a bowl or go dirt jumping, but anymore it gets dangerous real quick.
ive rode while being addicted to heroin and thats a different story...