Hi from Amsterdam (NL)

[Brammofan]

From Ted on his Electric Chronicles blog:

So what’s not to love about hub motors?  Unsprung weight.  Unsprung weight is the part of the wheel and suspension that has to respond to the road surface.  More about mass, actually, if you have very little unsprung weight the suspension has less mass to fight so the bike is more nimble over bumps.  When you put a 50+ lb motor in the wheel, that’s a big mass to deal with on the bumps.

There are several people working on motorcycles with hub motors.  The negatives and positives of these will emerge over time.  I'd be concerned with an unsprung mass like that when you're tooling around a curve at 50+ and you hit a bump. 

[Richard230]

I think getting rid of heat that builds up in the motor casing is a problem also. Hub motors are great for small slow speed scooters and motorcycles, but I don't think they will do very well when required to move a vehicle at high speeds for more than a few minutes - unless you water cool the motor and that is not going to make their unsprung weight any lighter..