Fitting 1,000 horsepower inside a single wheel is possible. Making it weigh the same as the components it replaces is the harder problem, and the one that YASA and Drive System Design appear to have solved. The complete in-wheel system, which includes the motor, a planetary gearbox, integrated wheel bearings, and shared oil cooling, comes in at 32 to 35 kilograms. Add up the mass of the brakes, half the driveshaft, wheel bearings, and upright it displaces, and the figures come out almost even. The motor itself is a 12-kilogram axial flux unit with composite carbon fiber rotors and a Hallbach magnet array that concentrates magnetic flux toward the stator rather than losing it through heavy back iron. Peak output is 750 kW, with 400 kW available continuously.
Unsprung mass is the reason most in-wheel motor proposals never reach production. Every kilogram added to the wheel assembly makes the suspension work harder to keep the tire in contact with the road, degrading both ride quality and handling response at speed. YASA's design avoids the problem by replacing the conventional braking system entirely rather than adding to it. That decision forces the motor to handle both propulsion and deceleration, which requires substantial power in both directions and explains why peak output sits at 750 kW. The payoff is a system that captures a large share of the vehicle's kinetic energy during deceleration, feeding it back to the battery. For vehicles spending time at a circuit or in repeated hard stops, that regenerative capture could allow for a meaningfully smaller and lighter battery pack without sacrificing usable range.
Drive System Design's test facility is where the engineering gets validated. A tilting platform rotates the entire assembled unit to 45 degrees, which approximates a 1G lateral cornering load by splitting gravity between the vertical and sideways axes. Those results feed into simulations that can model any cornering scenario without physically replicating each one. A second rig uses hydraulic actuators to push and pull on the motor shaft in all three axes simultaneously while the motor is running under load. A custom hub with paired tapered roller bearings transfers those forces onto a stationary plate, replicating what a spinning wheel would see during a lap. The rig applies braking torque at the same time. The most demanding test configuration simulates a 3G cornering event, which represents the peak structural load this system would face in a high-performance vehicle application.
Bottom line: Mass-neutral on paper does not automatically mean functional in a car, but what this video shows is that the structural and thermal case for the system has been taken seriously and tested under conditions that exceed what most road-going vehicles will ever see. Getting it into an actual vehicle is the remaining work, and that will be where the engineering either holds up or falls apart.