Induction motors tend to be quite a bit less efficient than permanent magnet motors though. Another option is to use permanent magnet motors that just don't us

Induction motors tend to be quite a bit less efficient than permanent magnet motors though. Another option is to use permanent magnet motors that just don't use rare earth magnets. The Netgain Hyper9 (fairly commonly used in EV conversions) for instance doesn't use rare earth elements according to EVWest [1]. It's bulky and not particularly powerful, but it has pretty good efficiency. [1] https://www.evwest.com/catalog/product_info.php?products_id=469 https://www.evwest.com/catalog/product_info.php?products_id=... I believe some dual-motor EVs use a permanent magnet and an induction motor, the idea being that you can use just the permanent magnet motor most of the time for efficiency, but the induction motor is there for more power.