Originally Posted by
pitchpole
Im curious where you got this idea. I have been running a rear hub motor just fine on 700C tires and my city has some really bad road surfaces in spots. I think this depends on how much you weigh...
I weigh 66kgs, and use a full rear hub motor, which is heavy to the tune of 9kgs - not the little thing with a pair of chordless battery motors in it. It also depends on battery weight (almost 200 cells weighing a further 10kgs) and i'm not talking about rough surfaces, i'm talking about taking a 90 lb bike over kerbs, bricks, tree roots, stairs...
So at this level one has a whole spectrum of duty to consider, and a 700C tyre is gonna be suitable only for the lightest of duties from my perspective.