Re: direct drive an 18T fixie sprocket?
the china 2 stroke won't be able to pull an 18t.
i mean, you'll have to pedal it up to 15-20mph for the engine to take over. they don't have enough torque. and it'll never reach it's top speed (which calculates out to 80mph or something.)
on a heavily modified engine with a 28 tooth, my bike is still rideable, but it struggles on big hills and against the wind.