Originally Posted by KoryWitkus
And what is the sprocket adapter for ?
These bikes use a joint that connects the sprocket to the spokes. This (in my mind at least) is very unsafe, and also puts uneven force on the rear wheel which is what cracked the frame of one of my other bikes. The sprocket adapter makes it so the engine drives the wheel from the hub to evenly distribute the force to the entire wheel. It also allows you to center the sprocket perfectly on the wheel, and even has some side to side movement if you need the chain to clear a thick tire.
I've been using one from phantom bikes for a while, and have not had any problems yet!