[jspatz1]

As mentioned, a high friction tread such as roughtop or wedgetop will simply shred the ball skin at high speeds. It is natural to think in terms of high traction material, but in reality the ball itself is already a high traction material, and more is not needed on the shooting wheel. We found a relatively smooth, hard surface gives the right amount of slip to avoid damage, while still accelerating the ball. We just left the hard, smooth rubber tread that came on the utility wheel we use.