Quote:
Originally Posted by Christ
Due to the laws of inertia and centripetal forces, I'd venture to say that you're correct on that, MazdaMatt.
But, you have to remember that they're removing the entire brake assembly from each wheel. Federally illegal in this country, as yet, but still a big step... have you weighed rotors? They're not light.
You're substantially reducing both rotating mass and unsprung weight, before adding a stationary (not rotating) mass which adds back unsprung weight.
Homework for someone: Is there a law that requires that vehicle braking systems be hydraulic/air actuated?
I don't think there is for a modified vehicle... or for a period correct vehicle. This means there is a loophole in the "you can't use it without brakes" arguement.
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Now you're asking even more from your 20 pound motors, as they'll need to deal with the resistance heating from converting that 621 amps of braking back into electricity and sending it back to the controller/batteries, or roughly twice the duty cycle if you're in stop-and-go. Then add resistive radiator elements to the car, since you can't overcharge the batteries, so if somebody starts at the top of a hill on a full charge, that electricity has to go somewhere. Finally, your motors have to be able to regenerate a LOT more than they output, because 40 horsepower worth of braking isn't going to be very good in a panic stop, or on a long downhill, or pulling a trailer...
And hope you don't blow a fuse, because then you're relying on your handbrake. Whoops, that's gone too, because you've eliminated the discs or drums it operates.
This is an interesting academic discussion, but any practical technology is unobtainium right now, so to go back to the OP's topic of "how about hub motors for my truck?", the best current answer is "fine for scooters, but not ready for prime time in automobiles, and won't be for a while."