Laissez said:
Yep, I have always spare chain and inner tube with me. The fear I have with hub motor is tire puncture during winter when it's going to be pain to change the inner tube.
The sudden-failure problems that can happen with middrives that also disable the pedal drivetrain also include:
--freehub or freewheel in the rear wheel
--gearing in an IGH, or it's overload shear pin
--the freewheel for the cranks at the drive itself
--bearings inside the drive on the crankshaft, etc.
--derailer on a multispeed non-IGH rear cluster
For hubmotors and tire/tube problems, there are some things that help minimize the time needed to deal with it, such as preparing connections for easy disconnect/reconnect, preferably right at the axle so you don't have a bunch of wire to tie down, and using motors with integrated torque arms so there's not a bunch of separate pieces to handle and put back just the right way.
I ride heavy-cargo haulers, these days using just big heavy hubmotors, so any tire/tube problem is a huge PITA, especially if I'm carrying cargo (cuz it might have to be unloaded to deal with the problem). So i understand the issues.
FWIW, I've only ever broken a handful of chains, all while riding...all of them by using motors thru the pedal drivetrain. I've worn out lots of chains with just pedals or with motors...but never actually broke any by only pedalling.