reviving this old thread just to tack on my own recent experiences - my 2018 colt started making those clicking noises. having replaced a bottom bracket before, i was not relishing the thought of tearing everything down and getting to it. so like you not only have to remove the crank arms, but you need to remove the bottom battery holder, pull out the controller (thankfully, on my bike at least, they hid enough wire under the controller to let you pull it free to access the connections underneath although this is by no means obvious since things are packed so tight around the controller).
anyhow i just kept on pedaling away for a LONG time and the clicking just stayed as-is for quite a while but at around 6.2k miles, the BB clicking more rapidly turned into squeaking, and the squeaking into grinding, and one day i saw a ball from one of the bearings roll onto my floor underneath the bike, so i figured it was finally time to tackle the replacement.
turns out this was WAY TOO LATE - i dutifully screwed on the bottom bracket tool, was relieved to be able to turn the drive side with great force, BUT only to have the end cap of the cup sort of shear off, leaving its threaded surfaces stuck in the bike. I then figured my only choice was to try and remove the bottom bracket from the other (drive) side (unplugging the torque sensor wire so it didn't unduly yank on the controller) but that sheared off fairly quickly. i tugged on the innards of the bottom bracket and i guess all of my pedaling through the squeaking/grinding noises totally wrecked the bearings so it was actually easy to yank the bottom bracket innards out, but now i am left with just a hollow bottom bracket shell still clamped to the frame with the threads from the plastic cups with no usable surface to try and exert force with.
at this point I reckon maybe the recourse is to take a hacksaw and try to compromise the BB shell right before getting to any frame/threads but since that includes some fairly tough outer bearing races figured now it was time to let a local bike shop take a crack so i'm crossing my fingers.
i think so far i have learned these things:
-now i see why surface604 decided to move away from these bottom bracket torque sensors. i feel like the design of the frame is such that water necessarily finds its way in (through the bottom wire entry or even just around the battery compartment and down? i have a little rust on the bottom of my controller) and over time sediment and rust and grime packs in around the BB? it's not uncommon for BB's to get all seized up and difficult to remove, but i feel like a BB with two plastic caps as with this bafang torque sensor rather than having at least one cap being part of the metal BB body seems to be adding risk. I suppose the problem is ameliorated if there were a BB torque sensor with just one plastic cap, but i still wonder whether more water enters the BB area on these frames than usual. these conjectures with a grain of salt or three because i regularly commute through terrible, salty and wet conditions so my situation may be exaggerated compared to typical use?
-PROBABLY had i seen to replace at the first sign of trouble, the bottom bracket would not have been so seized up and the caps easier to remove. by the time balls are falling out the sides, the plastic end caps have already been compromised to some degree, because there is a plastic wall that has to break (and a rubber grommet) before bearings can spill out.
-wonder if i cranked on the bb removing tool "too tight" which could also help weaken the end caps?
ah well. here's hoping the LBS has some luck!
