[bombcar]

The idea of a motor on each wheel independent has obviously been considered, but what is often ignored is the sprung vs unsprung weight.

You could develop a pretty amazing off-road vehicle with independent electric motors in each wheel, but it would be a relatively bumpy ride.

[shrubble]

The Mercedes 300SL, the Gull Wing of 1954, already had inboard-mounted brakes to reduce unpsrung weight. I would assume that any Mercedes engineer would be familiar with the concept...

[Wistar]

As do the Jaguar E and XJ types, and perhaps other Jags. The Audi 100, some Alfas and Lotus cars, too.

[adolph]

And the Humvee

[jacquesm]

Citroen DS as well:

http://www.citroenet.org.uk/passenger-cars/michelin/ds/image...

[bigiain]

And a bunch of Alfa Romeos (Suds and Sprints from the 80s/90s at least)

[benj111]

The 2cv did this as well. I'm undecided if this supports your argument though.

[lloeki]

Suspension design on the 2cv was a very specific consequence of the "egg" design brief:

> This suspension design ensured the road wheels followed ground contours underneath them closely, while insulating the vehicle from shocks, enabling the 2CV to be driven over a ploughed field without breaking any eggs, as its design brief required.

https://en.wikipedia.org/wiki/Citroën_2CV#Suspension

[impossiblefork]

The unsprung weight won't be changed.

There is one motor connected to each of the wheels, but there is a shaft between the wheel and the motor and a CV joint on this shaft, allowing the wheel to move relative to the motor, and the wheel is sprung.

There are cars with in-wheel hub motors. For example, MW Motors make on of their Luka models with in-wheel hub motors. Those must keep their motors light, and have the advantage that you get more space in the car at the expense of a tiny bit more bumpiness.

[chrisseaton]

> You could develop a pretty amazing off-road vehicle with independent electric motors in each wheel, but it would be a relatively bumpy ride.

Military EV prototypes are considering wheels-in-hubs, because they have complex suspension and because of under-armour, but yeah it means the motor is basically un-suspended.

[_carbyau_]

sprung vs unsprung is a ratio.

These vehicles are likely heavy enough that electric motors in the wheels might not change that ratio much.

And swap/repair would be convenient!

[bombcar]

And at something like 10k pounds empty, and with army dudes in the cab who nobody cares about getting bumped, it might be the way to go.

[jillesvangurp]

There are several cars that use this already. The issue is not so much ignored; but been dealt with. Multiple EV manufacturers have now successfully used this technology in vehicles. It seems the benefits outweigh the theoretical downsides.

Of course the question remains what happens in a high performance car at extreme speeds. But presumably, Ferrari and Mercedes know what they are doing and have considered this as well.

As for suspension; I'm sure there are ways to deal with that as well. I don't see how this should be any more bumpy than other vehicles for off-road.

A bigger concern would be what you'd do in case of a flat tire as that basically means losing an engine. And when you are in the middle of nowhere, getting some road assistance would not be that easy.

[benj111]

You have the wheel separate to the motor, so you just replace the wheel? Just like you don't currently have to remove the brakes when you change a wheel.

[jillesvangurp]

Not if the motor is part of the wheel.

[audunw]

But it wouldn't be part of the wheel... there's no reason for it to be, and it'd make the car impossible to use in countries with snow where you need to change the wheel every spring and winter.

[kolinko]

You change tires, not the whole wheels between seasons.

[ubercore]

At least here in Norway, you change the whole wheel.

[benj111]

Still, what tyre shop is set up to change tyres while still on the vehicle?

[chasd00]

Don’t those giant mining dump trucks have electric motors on each wheel? Although that’s probably for the low rpm torque advantage like diesel electric trains.

[bombcar]

They do, primarily so they don't have to have anything resembling a "driveshaft" or a transmission, because they're so big they don't actually "bump" over anything, more like crush it into submission.

[rektide]

The unspring weight is the main reason I havent placed an Aptera (also in-wheel axial motor) pre-order. I have a hard time imagining this fundamental of vehicle dynamics can be adequately worked around, but oh how I want to believe. Also keeping me from placing a pre-order; their pre-order site wouldnt let me check out in Firefox.