I seen lots of people with fixies with 2 gears, a coaster and a fixed on each side of the rear wheel. How hard would it be to have that coaster gear design setup with a chain to a motor? pretty easy I think. Find some guys who know their stuff, especially those fixie guys, they're the craziest.
Find a bike with 7-8 gears, make it a 5-6. install the coaster gear on the other side. No impossible, they make hubs and axles designed for that.
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