It would have been awesome if that article had, at any point, explained what an electric axial flux motor was, and why anyone might want one.
"In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing."
Don’t mistake your curiosity for everyone else’s
Hand waving.
you add planetary gears
>sprung mass
you can integrate all into one hub (breaks, bearings, gears etc) and it weights pretty much the same.
what you gain is more space for a bigger battery, torque vectoring, no loss on diff and CVs
You would get to delete about half the mass of the half-shaft but otherwise you are cramming a lot of stuff into the wheel volume and it all has to survive living out there. Now your HV wiring and any cooling connections to the motor have to flex with the movements of the suspension and probably need guarding against rocks and other road debris. I think all EVs now have the drive electronics tightly coupled to the motors - now that either has to be separated or made compact enough to fit and rugged enough to survive a much higher vibration regime. We do have small amounts of electronics on hub assemblies today (I'm thinking of electronic parking brakes) so there is some precedent but that circuitry is much less challenging than an inverter handling 100s of kW.
>no loss on diff
I doubt there's much loss from differentials in EVs. They don't have the bevel gear of diffs used in longitudinal layout ICE vehicles and mostly the gears in a diff don't move relative to one another (unless you are doing donuts!), so the whole cage mostly acts like a solid gear giving whatever final ratio.
No, it's hand waving because it doesn't explain how or why. That's what "hand waving" means.
Edit: a video from them on this particular YASA tech being discussed : https://youtu.be/m507ryWhc6c
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
I wonder why they need tree motors per axle.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
What would it mean to "turn off" traction control in a car with independent motors per wheel? (OK this is a 3-motor/4-wheel scenario, but hypothetically…)
With software control and independent motors, we're likely to see increases in low-traction capability (for the right price-point and probably aimed at particular buyers)
With separate front and rear electric motors, there's no center differential to worry about, and a sufficiently sophisticated motor control system can make it behave well on and off road.
Then there's braking. More driven wheels means more braking energy that can be recouped via regen. In traditionally rwd cars you lose out here because braking energy tends to be directed forward.
Also there's packaging. One large motor might impinge on the cabin.
Also you get benefits wrt mass production.
A smaller motor is easier to handle. Potentially could avoid the need for high voltage cables. Which eases repair.
https://www.instructables.com/Designing-and-Building-an-Axia...
Put the engine and its transmission to the wheel mounted next to each wheel.
No need for differentials etc, if they can work out a steering mechanism for each, then you've got 4WD with 4W steering.
In the video there's talk of how you can use them as regenerative braking as well, so have that as part of the wheel structure.
No axles, no differentials, independent suspension, electronically controlled power to each wheel, regenerative braking.
Gonna be a fun decade or more of innovation coming.
That BRM V16 is a close second though! It’s probably more impressive given it’s 50 years older than the Ferrari engine and was not designed by computers.
https://en.wikipedia.org/wiki/VR5_engine
We owned an vw inline 5 Passat (quantum in North America). Good engine and synchro awd.
Indeed not. The first ever electric motor was an axial flux motor built by Michael Faraday in 1821. It's definitely not a new idea.
https://en.wikipedia.org/wiki/Axial_flux_motor#Automotive
> Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and 296GTB, Lamborghini Revuelto, McLaren Artura and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10]
> In July 2025, YASA announced a prototype 550 kW (738 hp) 13.1 kg (29 lb) motor, equating to power density of 42 kW/kg, which the company claimed to be the highest ever achieved.[11] By contrast, the state of the art EV motor from Lucid Motors offers a 500 kW, 31.4-kg motor, or 16 kW/kg.[12]
> The first application of these motors will be in the High Performance Mercedes‑AMG GT 4-Touring Coupe.[14]