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Technology is the term we use for things that don't quite work yet.

Good design! Low unsprung weight while retaining direct drive benefits.

Bad hub wheel motor design.
Bad hub wheel motor design.

I’m not going in to the details on particular attempts at hub motors, but even if executed perfectly they are bad.

Unsprung weight means terrible handling and reduced road-holding capabilities!

Done, end of story, move on.

Good news: There is an alternative.

In-board electric motors: You place the motors in the center of the vehicle and use standard short drive shafts to bring the power to each wheel. The downside? Space… you need to fit two motors (remember you no longer have a differential) as close the center of the vehicle as possible and either have the entire motor pivot or have short angled drive shafts from each one.
By placing the center of gravity of each motor almost completely off the wheel you mitigate the unsprung weight to almost nothing.

There are a couple other problems with wheel motors, you need a massive amount of current and a motor that is efficient over a wide range of RPM’s. Modern high powered IGBT’s and MOSFET’s are probably up to the task and when integrated in to intelligent power controllers, they can drive various forms of electric motors at high levels of efficiency and power.

The second problem ‘massive current’ is a bit harder. Battery chemistry is changing rapidly, but it is still difficult to find chemistries than can supply large current, long cycle life, reasonable price, weight, size, safety and the ability to be mass produced.

All said, drop the stock differential, the stock drive shaft, the motor, the transmission, exhaust, emissions equipment and all the other ICE components that become redundant and then you might have a chance of building something that has a reasonable power to weight ratio and efficiency level.

One last thing, as an alternative you could place the motor where the transmission is on a RWD vehicle, keeping the existing differential and drive shaft (a 100 year old design). This adds additional weight, but you no longer have the space restrictions and gain a bit of gearing which might lower your peak power needs.

This Detroit Electric design is ancient but a good compromise.

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