so i binned my 5inch pretty hard into a concrete wall at the skatepark yesterday, one of those dumb low passes that looked way more clearance on the goggle feed than it actually was. anyway props are obviously toast, one arm has a crack i need to look at, but the thing that's bugging me is motor 3 just... doesnt spin up the same. like it spins but there's this grinding/rough feeling when i rotate it by hand and in betaflight the motor tab shows it drawing way more amps than the others at the same throttle percentage.

my question is do i just replace it or is there any point trying to open it up first. ive heard some guys say a bent shaft is fixable if you have a spare but i dont really know how to check if the shaft is bent vs if the stator windings are actually cooked. also not sure if i should be looking at the esc for that motor too since it was pulling weird current ? would a bad motor damage the esc or is that usually the other way around

the rough feeling when you spin it by hand is almost definitely a bent shaft. cooked windings usually still feel smooth or you'd smell something burnt. pull the prop off and look down at the shaft while you rotate it slowly ? you can usually see the wobble pretty clearly even without any tools. if it's wobbling even a little that's your problem and yeah you can press out the shaft and replace it if you have a matching diameter spare, but honestly for a 5inch motor it's rarely worth the hassle unless it's like a premium motor you really want to save.

as for the esc ? a mechanically bad motor drawing weird current can stress the esc mosfets over time but a single crash incident pulling a few extra amps shouldn't fry it. i'd just replace the motor and rebind it in betaflight and see if your current draw normalizes before assuming anything is wrong downstream.

also worth checking if any of the magnets chipped or cracked inside the bell, i had a crash once where the motor felt rough and i was sure it was the shaft but it turned out a tiny piece of magnet had broken off and was scraping the stator. could see it once i pulled the bell off. that kind of damage you basically can't repair so you'd be looking at a full replacement either way