The usual problem with wheel motors is unsprung weight, and the 90s was before batteries had decent energy density.

It sounds like something like a Prius, but with serial hybrid instead of parallel hybrid like the Prius was.

The context was clearly conventional automobiles. Nothing going over ~30 mph will ever be economically competitive with wheel motors instead of inboard motors. The physics are such that this will forever be true. Any materials advancement will improve both technologies and wheel motors can never catch up.

The prototype they had was on a modified 90's Intrepid.

https://youtu.be/er8ufDV87nQ

https://youtu.be/jHmxJPTWD-M

It had comparable of not superior acceleration to it's original combustion engine.

And cost more and had worse handling. There's no advantage.

Except being electric and costing essentially nothing in maintenance?

Also, the handling characteristics were really not as bad as claimed from most all experiments conducted.

I really don't understand where you're getting that from. For economy cars up to ~130kph hub motors are a very feasible alternative.

There are hub motors+rims right now with which you could build a ~150hp car, that will weigh less or comparably to old-fashioned steel rims, including axles, rotors and superfluous suspension components (around 30-40kg). For example, the QS Motor 273 with a power of 28kw (per wheel) given appropriate cooling, at a mass of 43kg. This is for a mass market, aluminum motor/rim. I assure you that with magnesium wheels and glycol cooling you can get this down under 43kg. These motors have a wholesale price under 2000$, too, and have been run at 180v 600A for short periods of time.

Here is also an actual study with data about the feasibility of hub motors in four-wheel vehicles: https://www.proteanelectric.com/f/2018/04/protean-Services3....

Yes, hub motors will always have a disadvantage as far as unsprung mass as improvements affect both sides of the equation. However, hub motors have very significant handling advantages that you cannot feasibly get any other way, such as per-tire regenerative braking, a perfect fully dynamic differential, perfect torque vectoring, optimal weight distribution, allows far superior suspension design, and so on. As a result, hub motors are still a very serious contender, and as the gaps narrows and investment ramps up we might see very high performance hub motors become a reality.

Another technology that will have to be evaluated is fully active suspension, which eliminates almost all of the disadvantages of hub motors and keep all of their advantages. Indeed, fully active electromagnetic suspension is entering limited mass production right now.

But yes, in the 1990s hub motors could not have made for anything more than an economy car with a top speed around 130-140kph economically. Which is exactly what they were meant for.

In-board motors, one per wheel, have all those advantages you state for wheel motors, but none of the disadvantage of excessive unsprung weight. Additionally, a bad pothole means only replacing a cheap wheel and not an expensive motor.

Steel wheels on a 112kW car do not weigh near 43 kg. Don't fall for the empty promises.

(Random first hit: 23 lbs for a steel wheel: https://www.amazon.com/dp/B01MA3OFTN)

They'll never be cost-effective for freeway-capable cars. I'll make a long term bet on it with anybody.

EDIT: your linked study says you can add features to somewhat make up for the excessive unsprung weight. Sure, which is why I'm pointing out not that it can't be done, but that it costs more for the same performance and always will (at Earth gravity and freeway speeds).

Steel rims alone? No. Brakes, plus axles and various power transfer components, as well needlessly complex superfluous suspension? Yes.

A very important distinction is also that the moment of inertia of a hub motor is not much bigger because the weight is concentrated in the center vs the extremities.

In-board motors, one per wheel, have the issues of still needing all of the weighty unsprung mass of a car but adding additional mechanical complexity in the transfer mechanism as well as just adding mass and taking up space in general, plus needing more cooling. I am willing to bet that the braking system alone in the average car is more than 28kg.

Besides, cars with hub motors that have less unsprung weight that the original car they were based one have been built, for example this one : https://web.archive.org/web/20090318173319/http://www.causec...