Performance tips for axial flux in-wheel motors. Learn how to mitigate unsprung mass and maximize torque density for EVs and UAVs with Beyond Motors.
.svg)
Performance tips for axial flux in-wheel motors. Learn how to mitigate unsprung mass and maximize torque density for EVs and UAVs with Beyond Motors.
The shift from centralized powertrains to distributed drive systems—specifically in-wheel or hub motor configurations—is the next frontier for high-performance EVs and light aviation. For CTOs and Lead Engineers, the primary objective is to maximize efficiency and handling while minimizing the mechanical complexity of drive shafts and differentials.
At Beyond Motors, we recognize that an in-wheel system is only as good as the motor's power-to-weight ratio. The axial flux motor is uniquely suited for this role because of its pancake form factor and superior torque density. However, integrating these units into a wheel hub requires specific engineering strategies to maintain vehicle dynamics and thermal integrity.
Here are the critical performance tips for optimizing axial flux in-wheel systems.
The biggest critique of in-wheel motors is the increase in unsprung mass, which can negatively impact suspension response and ride quality.
Performance Tip: Prioritize the highest possible power-to-weight ratio.
Our Beyond Motors AXM series is engineered to break the weight barrier. For instance, the AXM2 delivers up to 130kW peak power while weighing only 14.5 kg. By utilizing a motor that achieves 10 kW/kg power density, you can often offset the weight of deleted components like drive shafts and traditional braking systems. This "mass-neutral" approach ensures that the vehicle’s handling remains sharp even with the motors moved to the corners.
In a traditional hub motor, engineers often use a planetary gearbox to multiply torque, which adds weight, friction, and a point of mechanical failure.
Performance Tip: Use the cubic scaling of axial flux to run direct-drive.
Because the torque of an axial flux motor is proportional to the cube of its diameter ($T \propto D^3$), you can generate massive low-end torque without a gearbox. Our AXM4, for example, produces a staggering 950 Nm of peak torque. For most light EV and robotic applications, this allows for a direct-drive setup, which:
Wheel hubs are notoriously difficult to cool, especially when surrounded by hot brake rotors or enclosed in aero-wheels.
Performance Tip: Implement active liquid cooling.
Air-cooled hub motors frequently suffer from "thermal derating" during long hill climbs or aggressive driving. We address this with our patent-pending water cooling system. By integrating a liquid-coolant loop directly into the stator, the high-performance e-motors from Beyond Motors can maintain high continuous power without overheating. This allows you to design for sustained performance, not just 10-second bursts.
In a distributed drive system, a motor failure in one wheel can lead to dangerous torque vectoring issues if not managed correctly.
Performance Tip: Use Double Winding (2 x UVW) architecture.
Beyond Motors offers a Double Winding redundancy option on all models. This allows each motor to be driven by two independent inverter channels. If one inverter or winding fails, the motor continues to provide 50% torque. This is a mission-critical feature for autonomous vehicles and eVTOLs where "limp-home" capability is a mandatory safety requirement.
In-wheel motors are no longer a compromise; they are a competitive advantage when designed with the right technology. Whether you are building a low-floor bus, a high-performance racing EV, or a tactical UAV, the motor's ability to provide high torque in a compact, thermally stable package is the key to success.
Ready to simulate your in-wheel performance?If your project requires custom specs, sizing, or specific project requirements, our technical team can provide the precise CAD and efficiency data needed for your wheel assembly.
Start your hub motor simulation with the Beyond Motors Configurator
