I defer to any material or mechanical engineers, but it’s honestly amazing how hardy the humble bicycle chain is, for all that’s it’s usually – and unusually – put through. It’s basically some thin metal plates linked together by tiny roller bearings every few centimeters. Everything about it says it should explode into dozens of pieces under even light loading of human power

And yet it doesn’t. Well, not until a few thousand peak Watts slams into it.

My personal theory is that bicycle components on ebikes begin to lose a substantial chunk of service life not simply because of the higher power demands, but because of the instantaneous force. Whereas a human generates force at two peaks when turning the cranks one whole revolution, a mid-drive motor generates and sustains torque – and thus chain force – with no pauses while accelerating. That’s rough for the entire drivetrain, and maybe even parts of the frame. Though I’m of the opinion that the non-moving parts of a bicycle have so much excess strength that it’s usually a non-issue.

I’d actually be more concerned about rear wheel construction, since standard-laced spoked wheels are incredible except for: 1) axial loading (aka pushing the wheel sideways), and 2) sudden and heavy torque, which threatens the trailing spokes. Over time, the fatigue to the spokes could manifest in a wheel failure.