CIM Motor Direct Drive or Supporting Axle

[jman4747]

You will sacrifice speed with smaller diameter wheels and they don't have to be as wide as the ball. The ball just needs to hit the center of the wheel. Two side by side would give better accuracy but this application doesn't require it so a physical constant that keeps the ball mostly centered as it hits the wheel would be enough.

My suggestion would be to mount the 8mm hub to this wheel and on the other side use a 3/8" hub with this bearing at the end of the shaft.

If I were designing an FRC robot this assembly would be totally different but this application should't require it.