so i binned my 5inch pretty hard into a concrete barrier last week, props obviously shredded, frame took a hit on one arm but its still solid. replaced the props and thought id be good to go but now one of the motors is running noticeably hotter than the others after even a short hover. like cant comfortably hold your finger on it after 2 minutes whereas the other three are just warm.

pulled the motor off and spun it by hand, feels slightly rougher than the others, probably the bearings took the impact. no visible winding damage that i can see but honestly im not great at spotting that. question is do i bother trying to replace the bearings myself or just swap the whole motor. i have like 6 or 7 of these motors in a spare box so its not really about cost, more about whether the stator itself could be damaged and i just cant see it.

running T-Motor F40 Pro IV's if that matters. FC is showing balanced amps across all four on the ground but i dont fully trust that reading.

if you already have spares just swap the whole motor, not worth the hassle of pressing new bearings unless you're really into that kind of thing. bearing replacement on motors that size is finicky and honestly if it took that kind of impact the stator laminations could be slightly deformed even if nothing looks wrong. that'll show up as efficiency loss and heat over time. your instinct about the amps reading is right too, static ground test isn't gonna reveal much, the imbalance will be more obvious under load and throttle changes.

just put a known good motor on it, do a motor test in betaflight and look at the rpm curves if you have rpm filtering enabled, that'll tell you more than anything else. and check the motor mount holes on that arm while you're at it, concrete impacts can crack the arm internally without it looking busted.

yeah i had almost the exact same thing happen with a different motor brand and i tried to just run it thinking it'd be fine and eventually it let go mid flight and i lost the whole quad in a lake so. swap it lol