[EricH]

Originally Posted by DuzieInuKenshin

So far, we're just prototyping some shooter designs in order to shoot the ball vertically into a chute. The design we have so far is using 2 rubber wheels with a diameter of about 6 and a a wheel tread of about 1 in, so they're kind of small. We think the problem is that there is too little contact area between the moonrock and the wheel, but don't know how to fix that when the moon rocks themselves are full of holes. The only solution we have so far is to use 4 wheels and put belts between them to increase contact. Sorry if this isnt very descriptive. >_>

Wheels are a decent diameter, and using more wheels may help.

Though--let's look at this closely. You're shooting vertically into a chute. Straight up or straight down? If it's straight up, you might want to look into a belt system.