Obviously it’ll be very different to a normal one, but if it’s built into the motor, can you change it yourself or is it a motor out job?
Also, will it last longer than a normal bottom bracket due to the extra protection due to not being exposed to the elements? Has anyone had one fail on them?
Just wondering really.

They don’t have bottom brackets in the same was as a normal bike does. They have a power unit that the cranks are attached to.

There isn’t one, cranks are attached to the gearbox spindle/output shaft, most are splined.

I think the Rocky Mountain eBikes have a conventional bottom bracket, but they are the only ones.

It’s a bit like a BB, you’ve basically got bearings that require changing when they wear or get damaged, but no physical BB, well the bike frames don’t tend to have BBs anyway.

You usually have to remove covers and use bearing pullers, but most ebike shops can do this stuff at minimal cost.

There are bearings inside the motor casing which if opened voids any warranty.

If the bearings wear out during the time a motors under warranty it’s a new motor job, if out side of warranty there are people who replace the bearings or brands may offer cheaper assisted purchase motors.

I’ve changed bosch bearings, not hard but quite easy to damage other parts if your not careful. It is motor out, split casing remove sensor, circuit board etc. Oh and it required a hydraulic press for the output shaft bearing and making some press tools to do it right.

“ Has anyone had one fail on them?”

Yes, shimano 8000, at about 2000 miles, replacement motor was wobbling at 1000 miles, shimano are not particularly rebuildable (as I understand it no commercial rebuilders but the commercial rebuilders make the bits available) so I’m now on a levo, which has yet to fail(1500 miles) and is covered by commercial rebuilders (as are Bosch and Yamaha)

This bloke gets good press

The home of ebike motor parts

My advice would be to research spares availability, rebuildability and rebuild services prior to buying an ebike. (e.g. phone bloke above , other ebike rebuild shops now exist)

Performance line bearings has a YT channel.

A slight deviation from the thread but still relevant is that the design allows the cranks to be put on the wrong way, i.e. left on RHS and vice versa. I had an amusing few moments watching my mate try to get clip out of a set of SPD’s that were effectively on backwards. It was a bugger to clip in and near impossible to clip out. It took him quite a while to figure out what was wrong. He got his own back after my ebike came back from the shop with the pedals reversed, I use flats so it didn’t become apparent until my pedals unscrewed and fell of mid ride.