Somewhere in an Oxfordshire test lab, there is an electric motor that weighs about as much as a bag of dog food and makes more than 1,000 horsepower. That alone would be a story. But the company behind it, YASA, has now done something stranger with it: it put the motor inside the wheel.
If it works the way YASA says, the next generation of electric cars could lose their driveshafts, shrink or delete their rear brakes, and shed as much as 1,100 pounds. Almost nobody outside the engineering press has noticed. Here is the whole story, with the 126-year history that makes it so unlikely.
A motor shaped like a pancake
Nearly every EV on the road uses a radial flux motor: a cylinder spinning inside a ring of copper windings, with the magnetic field pointing out from the center like the spokes of a wheel. YASA builds the other kind. In an axial flux motor, the rotors are flat discs and the magnetic field runs parallel to the shaft, so the whole thing comes out short and wide, more dinner plate than soup can.
The name stands for Yokeless And Segmented Armature, which describes the trick that removes most of the heavy iron from the stator. The result is a motor that is unusually light for the torque it makes. Ferrari uses YASA motors in the SF90 Stradale, Lamborghini uses them in the Temerario, and Mercedes-Benz liked the technology enough to buy the company outright in 2021. YASA opened the UK’s first axial flux motor super-factory in May 2025.
Then, in October 2025, it announced a prototype that hit 750 kW on its dynamometer while weighing 12.7 kg. That works out to 59 kW per kilogram, which YASA calls an unofficial world record. For a sense of scale, YASA says that is three times the performance density of today’s best radial flux motors.
Then they put it in the wheel
Six weeks later, YASA showed what the record was for. It paired the motor with a new 15 kg dual inverter rated at 1,500 kW, the electronics that turn battery power into something a motor can use, and packaged the pair as a prototype in-wheel powertrain. YASA calls it the first “mass-neutral” in-wheel motor, meaning the parts it removes from the car should weigh about as much as the parts it adds to the wheel.
The numbers it attached to the idea are big:
- Up to 750 kW per wheel at peak, over 1,000 hp, with 350 to 400 kW continuous by YASA’s estimate.
- No driveshafts, because there is nothing left in the middle of the car to connect to.
- Smaller rear brakes, or none at all. A motor this strong can slow the car hard by running as a generator, so YASA says the rear discs and calipers could be cut down or removed.
- About 200 kg lighter on a modified version of today’s cars, and up to about 500 kg on a car designed around wheel motors from scratch.
Toggle the panel above between today’s layout and YASA’s two versions and you can watch those parts fall away. The pitch is not only about speed, either. YASA says the system scales down from hypercar outputs to ordinary performance EVs, and that freeing the middle of the car gives designers new room for cabins, batteries and aerodynamics.
YASA founder and CTO Tim Woolmer was careful to say it is “still early days” and that the system is in testing and development. The company has also said the prototype is not intended for immediate production.
Why nobody has done this already
Ferdinand Porsche put motors in wheel hubs in 1900. NASA drove them on the moon. So why does almost every EV still have its motors in the middle?
One phrase: unsprung mass. Everything the springs hold up, the body, seats, battery and you, is sprung mass. Everything below the springs, the wheel, tire, hub and brake, is unsprung. That lower group has to follow every bump in the road, and the heavier it gets, the harder it is to keep the tire pressed down. Ride gets busier and grip gets worse. Hang a heavy motor in the wheel and you make the problem bigger in exactly the wrong place.
A motor in the wheel also lives a rough life. It takes every pothole directly, sits in spray and road salt, and has to be cooled and sealed in a space that used to hold a brake. Those are engineering problems rather than physics problems, but they are the reason earlier attempts stayed niche.
That is why the 12.7 kg figure matters so much. A motor this light, doing the job of the brakes and shafts it replaces, is the first serious answer to the unsprung mass objection. It is not the only one. Slovenia’s Elaphe, which built the four wheel motors in the Lightyear 0, argues the real penalty can be as little as 35 pounds per wheel once you subtract the parts that go away. And a test drive of a DeepDrive prototype suggested the old fears about noise and handling no longer necessarily apply.
The other reason is business, not engineering. Lordstown planned a pickup on licensed Elaphe wheel motors, and Lightyear actually built a car with them. Both companies ran out of road. Great hardware has never been enough by itself.
Who else is racing for the wheel
- DeepDrive (Munich). Backed by BMW, which has road-tested its dual-rotor motors, and partnered with Continental on a combined wheel motor and brake. Its top RM2400 makes 250 kW and weighs 37 kg. Autocar reports a camouflaged Neue Klasse-style BMW coupe testing with no visible brake calipers, which hints at wheel motors, though BMW has not said so.
- Hyundai and Kia. Their Uni Wheel, shown in late 2023, takes a different route: a clever gear linkage that moves the reduction gear and main drive parts into the empty space inside the wheel hub, freeing up floor space for purpose-built vans.
- Elaphe (Slovenia). The veteran of the field, now pitching its motors at fast, exotic cars after supplying Lightyear and signing with Aptera.
What makes YASA different is the parent company. A startup needs a carmaker to take a chance on it. YASA already belongs to one.
What we are still verifying
- The record is YASA’s own. The 59 kW/kg figure was measured on YASA’s dynamometer and has not been independently certified. The 350 to 400 kW continuous rating is an estimate.
- The weight savings are claims. The 200 kg and 500 kg figures come from YASA, not from a finished car on a scale.
- The 2026 update has not arrived yet. YASA promised more detail on the in-wheel program this year. As of late October, its newsroom has not published one. Its most recent news is UK government funding to develop axial flux motors with no heavy rare earths, which would matter a lot if these motors ever go mainstream.
- No car has been announced. Not by Mercedes, and not by anyone else.
We will keep watching. When this motor shows up under something with a license plate, you will hear it from us first!
Quick answers
What is an in-wheel motor?
An electric motor mounted inside or right at the wheel, so it drives that wheel directly instead of sending power through a central gearbox and driveshafts.
Can I buy a car with in-wheel motors today?
Not a mainstream one. The Lightyear 0 used four of them but production stopped in January 2023, and Aptera’s solar car, which plans to use them, is still raising money to reach production.
Would in-wheel motors replace brakes completely?
YASA has only talked about the rear axle. Its claim is that regenerative braking could shrink the rear brakes or remove them, not that a car would drive without friction brakes altogether.
How is this different from the motors in today’s EVs?
Today’s EVs mostly use radial flux motors mounted in the middle of an axle. YASA’s is an axial flux design, flatter and much lighter for its power, which is what makes putting it in the wheel realistic. For how today’s cars actually compare, our EV Range Chart covers 178 of them.
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