Direct-drive sim wheel

A force-feedback racing wheel built around a hoverboard hub motor, developed through three design generations.

Personal project, 2025 to 2026

About 12 Nm of direct-drive force feedback for about $100.

Role: Design and build
Tools: SOLIDWORKS, machine shop, FDM printing
Electronics: ODESC, FFBeast, 14-bit magnetic encoder

Problem

A motor built inside out

A direct-drive wheel needs a motor with high torque at low speed, and a hoverboard hub motor delivers that for very little money. The catch is that a hub motor is built inside out: the outer hub spins while the shaft stays still.

So the hub has to drive the steering wheel while also reporting its position to an encoder, and neither job has an obvious place to attach.

Design

One failed conversion, one better idea

The first design converted it into a shaft-driven motor: I faced off the housing, pressed out the shaft and machined a replacement in 316 stainless. That damaged the bearings and put chips in the magnets, and the motor bound. So the second design leaves the motor untouched.

A clamp in the hub's outer groove drives the wheel on friction and bolt load, which SOLIDWORKS FEA confirmed for the roughly 12 Nm output. It carries a higher moment, so the mounting had to be stronger.

Build

Printed structure, machined where it counts

An aluminum coupler clamps the motor shaft on its flat and bolts to a support plate. Most of the structure is 3D printed, and only the high-load parts are machined from aluminum. Power comes from a 24 V supply salvaged from a broken Ender 3, driving an ODESC flashed with the open-source FFBeast firmware.

With no way to center a magnet on the sealed motor, a 6:1 GT2 belt with an idler carries position to a separate standoff pulley holding the magnet and encoder.

Result

Direct drive, and a third design in CAD

The second design gives real direct-drive force feedback for about $100, with electronics and purchased parts as the only real expense.

The third design, in CAD now, turns it into a finished product around the same sealed motor: a hub that clamps the 138 mm lip from both sides, 120 GT2 teeth printed directly on the hub nose, an MT6701 encoder in a sliding pod, and a one-piece cover over the electronics.

Engineering drawing of the replacement 15 mm motor shaft — Drawing for the replacement shaft in the first design.

Finished 3D printed steering wheel on a wood floor — The printed wheel from the second design.

Exploded render of the third sim wheel design — The third design, exploded: base, motor, hub and wheel.