I've never been to china but what's their city road quality like?
An extra 70lb at the wheel is going to make the already terrible durability of low profile tires worse (and you can't design for a smaller rim because you need space for the motor).
An extra 70lb at the wheel is going to make the already terrible durability of low profile tires worse (and you can't design for a smaller rim because you need space for the motor).
It's even a problem on trains - early electric trains had connecting rods between the motors and wheels just like steam trains. Later ones have the motors in the bogeys, but the motors are sprung and can swivel on the same axis as the drive gear.
Now replace the entire car with a 75lb electric motor in each corner and you've got the same problem but less extreme. It beats the crap out of the rim and tire. This wouldn't be too big of a deal but the hub motor all but forces you to use big rims and low profile tires which are already not that durable for reasons you can Google.
The tire wants to go in a straight line (inertia).
When a tire bounces over a bump, the springs push it back down onto the road. The heavier the wheel and the arms, the longer the tire has poor (or no!) contact with the road. No contact = no handling.
It's like hydroplaning on a dry road. Scary shit. Potentially fatal on a curve.