If the drive source is attached directly to the uniwheel, then handling radial drive inputs isn't required and the uniwheel isn't necessary. It's effectively a

If the drive source is attached directly to the uniwheel, then handling radial drive inputs isn't required and the uniwheel isn't necessary. It's effectively a hub motor with reduction gears at that point. Once the motor is mounted remotely from the uniwheel and the uniwheel is handling radial offsets, then we need to prevent the axle from getting pushed around radially. Rotating shafts that deflect introduce off-balance vibration and destructive mechanical loads. If the motor is located very near the uniwheel, keeping the shaft's free length very short, the motor's output bearing does effectively provide that support. Then we're only constrained by relocating the suspension elements. Thrust bearings are for the gears. The depictions show helical gears, which would surely be necessary when operating at transportation speeds for noise reasons. Helical gears experience axial forces, which would need to be handled for each gear. Mainly on one side for ICE drivetrains, since coasting loads are small, so one side could get away with a ground and hardened rub surface. EV's using regenerative braking would need robust thrust handling on both sides. Herringbone gears would eliminate the axial thrust issue, at substantially more expense. The easiest method is to separate the gear areas with a central runout groove so you'd have a hope of grinding in a decent surface on the faces, then it's only a little more than double the work; effectively cutting two gear shapes per gear plus the runout. https://en.wikipedia.org/wiki/Herringbone_gear https://en.wikipedia.org/wiki/Herringbone_gear