Quote:
Originally Posted by Ryland
I don't see what the big deal is with having a drive shaft, it would allow you put the motor in a more protected location, reduce your unsprung weight, use a cheaper motor, use better mechanical brakes (yes, you can skid to a stop with regen brakes, or just by shorting the motor, but I like redundant brakes!) with all of that said, I like that motor design, it's close to what some of the wind turbines are using for an alternator, it's also close to what my bicycle uses for a hub motor, of course with a bicycle like mine it's all unsprung weight!
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I can't speak for everyone else, but my problem with it is that it's unnecessary. Why bother with a drive shaft and axle and friction brakes when you can have AWD and greater efficiency with less overall AND unsprung weight. The hub motor should occupy (I don't know how exactly PML sets their system up) the space formerly taken by the brake disc, and spindle, both of which are fairly solid pieces, so in most cases you'll be trading dead even on weight. The hub motors will need some braking component in them for parking anyway, so there's your redundancy.
On the drive end of the car you'll be shedding weight due to losing the driveshaft, which is unsprung. CV shafts are lighter than the solid axles found in some RWD applications certainly, but you're still losing weight where it counts. Add to that the huge amount of rotating mass you've just eliminated, and I see no benefit to a traditional system with the exception of home conversions.
