[Fabulist]

Doug,
"You really have to appreciate what's possible with a clean, purpose-built motor/inverter package."
You mean like the Protean Electric in-wheel motor package?
http://www.proteanelectric.com/

This is very impressive. Particularly since it does away with the need for a differential as well as a gearbox and probably friction braking as well.

 

[Fabulist]

RE: Fisker Surf reservations

So what's wrong with wheel motors? Well one issue is the unsprung weight which gives unfavorable driving dynamics. Another is that you can typically get more power per unit mass by simply designing a larger single motor rather than multiple smaller motors.

Then there are the normal regulatory concerns.

so there are some certifications (such as the one for Anti-Lock Braking) you can't pass in a car with no drivetrain. These rules would need to be re-written to allow vehicles with in-wheel motors to be certified, which is obviously not going to happen without significant money and time spent lobbying--not a fight a small startup company should take on if it can avoid it.

So basically no serious manufacturer is considering wheel motors for the near future. I suppose they could help the Surf get more trunk space, but it would be at the expense of performance.

This is not my area of expertise and I have no reason to disagree with you. I just want to point out that the there are very good technical reasons against using Karma's pure electric drive train also, but Fisker has made it work and there is equal possibility that the issues with the in-hub direct drive systems can also be resolved to make that an option some day. After all, this type of drive system acquitted itself in the harshest possible driving environment in history over 40 years ago: