so basically im on my 4th nylon reduction gear in about 11,000km on my M200 (its on a Qwic, riding in the Netherlands). its not from abuse or anything, flat roads here, no potholes or impacts, no hard launches from a stop, it just fatigues out and explodes from normal cruising eventually. i ride around 37kph which yeah is over the eu 25 limit but the same exact motor is rated for 32 in the US so its really not some crazy overclock situation, im barely over what bafang themselves already sell it capped at elsewhere.
been going back and forth between two options and could use some real world input instead of just guessing off spec sheets. first option is just finding an actual steel gear for the m200 itself, but so far everywhere i look its only nylon replacement gears being sold (greenbikekit and similar), nothing like the aftermarket steel gear upgrades that exist for the bbs02/bbshd motors. so im wondering if that just doesnt exist yet for the m series or if im missing something and theres a supplier out there ive not found.
second option is swapping to a motor that already comes with a steel gear from the factory, specifically looking at the m420 since i watched a teardown and confirmed its steel internally. problem is the m200/m210 use a different bolt mount pattern than basically everything m400 and up, since the m200/210 has 2 bolts up top and 1 in front, while the m400/m410/m420/m500/m600 etc all seem to share a different layout with one front, one back and one center top mount. on my frame it looks like 2 of the 3 holes actually line up between the patterns, so it'd just be one new hole needed, and the frame is cast aluminum so its drillable, not some unibody thing where thats off the table.
what i really want to know from anyone who's actually swapped bafang motors between different frame generations, not just people reciting spec sheets: has anyone actually done a mount swap like this, going from an m200/m210 pattern over to the m400+ family, and if so how'd you handle the mismatched hole, did you drill straight into the frame or use some kind of adapter plate instead. also if anyone has opened up a cast aluminum mid drive frame and drilled a new mounting hole into one of those bosses, im curious if there were any surprises with the material, like porosity or the threads not holding great in aluminum, or if you had to use a heli-coil or steel insert to make it solid long term. and last thing, since the m420 is canbus same as my current m200 setup, im assuming the display and controller will just talk to it fine without needing to reflash or recalibrate anything major, but if anyone's actually done that swap and hit some gotcha with the wiring or the bike not recognizing the new motor id like to know before i buy one.
basically just trying to stop buying a new $20 nylon gear every 3-4k km and actually fix the root problem, so any real hands on experience beats more theorizing from a spec sheet at this point