The future for EVs might not be as brightly charged as we could have hoped for after a recent ban on subsidies by the freshly re-elected President Donald Trump. Not to mention the grim environmental and social issues at hand currently. Despite this, a Finnish company persists in this field and has invented something astounding called the Donut — and no, it is not the kind with frosting and sprinkles.
First we had the wheel, now we have the Donut
CES 2025 saw the debut of a family of in-wheel electric motors by Donut Labs. The company, whose motto is “Redefining electric mobility across all industries”, has spent close to a decade trying to perfect an in-wheel motor that actually works, also known as the holy grail of the EV industry.
The aim of these motors is to outperform current individual-wheel drive (IWD) systems, which are widely used in today’s EVs, whilst simultaneously surpassing competing in-wheel motor technologies that are still in the prototype stage.
Drawing from its name, Donut Labs’ innovative design takes on the look of an empty metal cylinder with tapered edges. This design could mark a huge shift for EV propulsion systems with implications related to vehicle performance, cost, and design flexibility.
How do EVs actually work?
Electric vehicles rely on IWD systems with each wheel being powered by an independent motor. This vastly differs from the tradition internal combustion engine which uses a central drive train. The IWD system design allows for features like torque vectoring and tank turning, where wheels on opposite sides rotate in reverse to pivot the vehicle on the spot. It is used in vehicles like the Tesla Cybertruck and Rivian R1S.
Mechanical components like drive shafts and differentials are still used to run these systems which ultimately wastes energy and increases cost at manufacturing and over the lifetime of the car.
Hence the research in the in-wheel motor or hub motor. Donut Labs aims to eliminate these components by integrating the motor directly into the wheel hub. The motor will drive the car directly from the wheel with no transmission or extra pieces. At its core, this design is a simplification of the architecture of the vehicle which will in turn reduce drivetrain losses.
Application of this design
Technical challenges and concerns regarding unsprung mass affecting ride quality has slowed down the adoption of in-wheel motors. Until now, theses concerns, along with the matter of long-term durability have limited the application to EVs. As a result, costs and poor performance were cited as the reason most efforts could not make it beyond the prototype phase.
Donut Labs CEO Marko Lehtimäki shared in an interview with Fast Company that Donut motors has been 7 years in the making, “starting with the idea of rethinking what propulsion systems and whole system architectures could look like in different kinds of vehicles if there was a high performance and low mass in-wheel motor available.”
Lehtimäki shared that the Donut Labs team went through several design generations and endless smaller iterations combining different winding techniques and magnet configurations before identifying the right ways to provide the highest performance while using common and inexpensive materials.
Overall feedback has been positive but drivers do share a concern for missing the roar of the traditional engine. “Many riders initially worry they’ll miss the roar of a traditional engine, but after just a few minutes on our electric bike, they discover that the near-silent torque is every bit as thrilling, if not more, than engine noise,” Lehtimäki countered.
Fans of sci-fi could live out their cyberpunk fantasies without having to deal with the notion of a dystopian future with this electric bike.