A bottom bracket mounted Pinion C.12 transmission runs 12 gears (grip shift) and over 600% ratio from gear 1 to gear 12. I bought a reasonably priced Priority 600x mountain bike (now replaced by two newer models) with this system. No derailleur, no chain, no lube. Two cogs/sprockets, one at the pedals, one on the back wheel. A carbon fiber belt drive. Not an e-bike. Easy to maintain. The extra cost is worth it avoiding the hassle.