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- The in-wheel motor principle explained simplyUnlike conventional electric motors positioned under the hood or in the floor, in-wheel motors are installed directly inside the wheels.
- On the same platform, you could theoretically get a front-wheel drive version with two in-wheel motors, a rear-wheel drive, or even all-wheel drive with four units.
- The Korean manufacturer is betting on this technology to optimize the interior space of its future electric vehicles by freeing up the space normally occupied by transmissions.
Ferdinand Porsche understood it all back in 1900. His Lohner-Porsche integrated electric motors directly into the wheel hubs, creating the first all-wheel drive vehicle in history. This in-wheel motor technology seemed promising, yet more than a century later, you’ll hardly find it in any production electric vehicle. This absence is even more puzzling given the theoretical advantages seem substantial.
The question deserves asking: if this technical solution offers so many benefits on paper, why do automakers continue to avoid it? Between technological promises and industrial realities, wheel-integrated motors reveal a fascinating paradox in the modern automotive industry.
The in-wheel motor principle explained simply
Unlike conventional electric motors positioned under the hood or in the floor, in-wheel motors are installed directly inside the wheels. This integration eliminates several traditional mechanical components at once: driveshafts, differentials, and much of the transmission. Power is transferred directly to each wheel without intermediaries.
This configuration offers remarkable architectural flexibility. On the same platform, you could theoretically get a front-wheel drive version with two in-wheel motors, a rear-wheel drive, or even all-wheel drive with four units. Manufacturers could diversify their ranges without completely rethinking their chassis, reducing development costs.
Impressive theoretical advantages
Energy efficiency constitutes the most convincing argument. In a traditional system, each transmission stage generates mechanical losses: gears, differentials, universal joints… These losses can represent between 10 and 15% of total power. In-wheel motors eliminate these intermediaries, maximizing energy delivered to the wheels.
Traction control also reaches an unmatched level of precision. With each wheel having its own motor, torque management becomes extremely precise. Imagine being able to instantly modulate the power of each wheel according to grip conditions, or even create torque vectoring effects to improve agility in corners.
Direct transmission without mechanical losses
Individual torque control per wheel
Simplified vehicle architecture
Increased platform modularity
More space for batteries
Technical challenges hindering adoption
Unsprung mass represents the main obstacle. Adding several pounds to each wheel significantly degrades suspension behavior. The wheels become less responsive to road irregularities, directly impacting ride comfort and grip. This additional mass also puts more stress on shock absorbers and springs, accelerating their wear.
Exposure to the elements constitutes another major challenge. Unlike motors protected in the cabin, in-wheel motors directly face water, salt, and gravel projections. They also absorb all shocks transmitted through the wheels: potholes, curbs, various obstacles. This exposure compromises their durability and complicates maintenance.
Cooling also poses a problem. Electric motors generate heat, especially during sustained acceleration. Dissipating this heat in the confined space of a wheel requires complex engineering solutions: forced ventilation, special rims, dedicated cooling circuits.
Emerging solutions and concrete projects
Renault is taking the step with its future R5 Turbo 3E, which will integrate two in-wheel motors on the rear wheels. Each unit will develop 268 horsepower, for a combined power of 536 horsepower. This demonstrator project will allow testing the technology in real conditions and evaluating its commercial viability.
Hyundai is developing the Uni Wheel project, aiming for broader application. The Korean manufacturer is betting on this technology to optimize the interior space of its future electric vehicles by freeing up the space normally occupied by transmissions.
Commercial market leading the way
Commercial vehicles might well democratize this technology. Neapco, in partnership with Elaphe, has designed the SuperBear, an in-wheel motor intended for urban delivery vehicles. This system integrates a two-speed gearbox and remains compatible with standard rims, facilitating its adoption.
This pragmatic approach bypasses several pitfalls. Delivery vehicles operate at reduced speeds, limiting cooling issues. Their professional use also justifies an initial extra cost, offset by energy efficiency gains and reduced mechanical maintenance costs.
The failure of the Lordstown Endurance nevertheless illustrates the risks. This American electric pickup promised four in-wheel motors and a range extender but never reached commercialization due to industrial and financial difficulties. Technological ambition is not enough without mastered industrial execution.
The democratization of in-wheel motors will ultimately depend on an established manufacturer’s ability to offer a reliable and economically viable solution. Current projects from Renault and Hyundai could provide this trigger, finally paving the way for this century-old technology that’s just waiting for its moment to transform the architecture of electric cars.
