High torque motor

Very roughly, more motor mass means more torque.

I think the Chevrolet Spark EV is an interesting example. For some reason GM decided to use a high-torque/low-speed configuration for this car, with about a 3.5:1 overall drive ratio, so the motor is big and produces lots of torque. The replacement Chevrolet Bolt has a more normal drive ratio, so the motor has to turn about twice as fast but only needs to produce half as much torque for the same torque to the wheels; the Bolt motor is much smaller, lighter, and more powerful than the Spark's motor. So the Spark design made no sense, but the Spark's motor might be handy for someone wanting to run only a car's original final drive for reduction... but it's intended for the usual 360 V or so of modern EVs.

Rusted B&B said:

Maybe a Warp or ac34 kind of thing direct to a transfer case of some sort?

Click to expand...

People building 4WD conversions often consider using the transfer case low range all of the time to get enough reduction gearing, and that doesn't generally work because

• transfer case input speed rating is limited
• low range is often noisy straight-cut gears
• low range may only be available in 4WD, which doesn't work on the street without a centre differential.

Fortunately, none of these factors are a problem for a rock crawler