If you doubt Tesla's engineering then you need to watch this
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Only rotor. And that is not that hard.
Or you should use sealed ball bearings. Also, centrifugal force for bearing much less that for the rotor, since diameter of rotating parts is much smaller. Vaccum cleaner turbines runs at 20-30K RPM, and ball bearings perfecly OK without forced lubrication for many years. SKF gives limiting speed for randomly taken W628/8-2Z bearing at 45K RPM f.e.
I had the wrong model. I was envisioning the rotor running in a planetary outer bearing race but with the hub connected to the wheel. But that's wrong because it couldn't be direct drive, the wheel does not turn at 18K rpm of course. I'm going to have to go research the per-wheel drive train.
It's a bad idea to put huge mass of motor into the wheel. You should keep unsprung mass as low as possible. AFAIK, Teslas have usual wheels with CV joint ended semiaxles connected to differential - reduction gear - motor assembly. That assembly looks like letter T, where top bar ends is a motor and reductor and vertical bas is differential. Nice and simple design, but everything is totally ruined by unsing highly ineffective and insane expensive chemical battery with ridiculously low energy density as power source for that nice drivetrain, making all thing senseless. Electric passenger cars have no future unless normal power source will be invented.
Yes. I had just researched the motor-to-wheel connection, which looks a bit weird but now I see there is a simple fixed gear reduction in the housings. Instead of the complex mechanism in a gas vehicle transmission, the speed reduction from the electric motor is handled by simple fixed gears and computer control of the motor speed.
Now as for the power, we are still waiting for Doc Brown to release the Mr Fusion powerplant to use instead of batteries.
Yep. And if you use asyncronous motor or synchronous reluctance motor it is also extremely cheap and reliable, since the only copper is in stator windings, there are no expensive rare-earth magnets and there are no brushes. Also, electric motors have high torque at 0 RPM, so no any need for clutch.
Power source should be of same simplicity, reliability and cheapness, and there could be huge breakthrough in our means of transportation.
And if we are talking about Doc Brown, the flying option will be necessary too. It is much easier to fly even, on some small old Cessna/Piper/Beechcraft, than to drive the most advanced car. :)
PS: IIRC, Doc Brown didn;t invent Mr.Fusion and flying option, he upgraded car in the future. And since his future with flying cars and other stuff was in 2015 we are definitely in some wrong and weird timeline.