Status: First iterration working · in redesign

A self-contained corner unit: hub motor, disc brake, and suspension fork, bolted together as one replaceable assembly.

Why not just buy it?

Barrier 4: not sold as a product at all.

We could buy every part of this module off the shelf, and did. Suspension forks, disc brakes, and hub motors are all mature bicycle commodities, available in quantity one, with datasheets, from suppliers who will still exist in ten years. Nothing here was hard to source.

What nobody sells is the assembly. Car suppliers sell corner modules but it’s still not mainstream; none exist at this scale, and none are designed to be moved between chassis. So this module is using parts that are already standard in a way that is modular in easy to integrate on chassus we did not think about yet.

What we built

We built a bike fork with a front hub motors, standard disk brake. Our first attempt was to have a classical steering with pushrod but this require adaptation for every chassis. we are now working on a custom part to use brake line to transmit the steering input and turn the fork.

Why it is built this way

The module exists to make vehicle topology cheap to change.

Number of wheels, track width, wheelbase, and seat layout are all questions we do not yet know the answers to, and all of them normally require redesigning suspension and drivetrain together. By fixing the corner as a unit and standardising how it bolts to a chassis, those become frame questions only. We can build a new chassis in weeks without touching anything that moves, brakes, or carries current.

The choice also happens to satisfy the repairability requirement from Making It Viable: every wearing part in the module is a bicycle part, serviceable by any bike shop.

Open questions

• Does a bicycle fork survive the loads of a vehicle several times a bicycle’s mass, over years rather than seasons?
• How much does unsprung mass from the hub motor cost us in comfort and grip?
• How can we improve the interface to the chassis (its suboptimal)

Interested in any of these? Come talk to us.