two years ago i brought a Marin east peak mountain bike in the hope of making it electrically powered with a limited budget i was able to get my hands on a easy shopper powabyke no battery's but i didn't care as i only wanted the hub motor i then brought a 15ah battery and a 60v 30 amp controller powered from a dc to dc buck boost convertor which took the 48v up to 60v. i split the hub motor wheel down for a good clean and to add extra thick power cables and put a set of 4 brushes on the commutator in the X configuration to help split the load and prevent burning the rotor windings out. This is still is working very well. How ever after two years of continuous running down muddy lanes , snow rain and steep off road hill sides the internal drive train gears have stripped the teeth the rest of the hub motor is good and strong still, ive replaced the stripped gears for spares i had but these gears are different ratio not only is the top speed decreased ( the torque is higher as expected ) but searching online can't find any replacement gears any websites that any one can throw at me would be highly appreciated 
