by Burgerman » 02 Jan 2023, 21:19
Because they use 12 inch wheels. 14 inch wheels. 2 different 3 bolt hubs, and a 4 bolt one, some with differing offsets to keep chair narrower ith thinner tyres and they make minor revisions to design internally year on year for reasons they only know. Remember tat even the cable length changes a part number. So mid drives or chars with 12 inch whels may both be linix 6mph 4 pole but be different RPM, or different connector length, different hub with different offset and / OR stud PCD
They all "fit"... But maybe needs your old hubs, or a motor compensation change or whatever. And some go the opposite way. So you swap a different part number and your left right/back forwards are all wrong. Again no prob if you have a programmer but they dont want that when someone swaps a motor...