[Alex357]

The one roller vs. two roller difference is indeed significant. Two rollers allow for more controlled motion because of better release of friction. One roller wheels have a 50% higher coefficient of friction causing for more draw and no extra pushing power for the cost.

To answer another question, building the wheels was a very long process. We prototyped throughout the summer in our SRP (Summer Robotics Project)... our team doesn't have an off-season really. Anyway, deciding to make and use these wheels during the six weeks isn't really feasible. There's a lot that goes into the process, from hubs to molding rollers. You cant go out and buy these wheels pre-made, so there's a lot of hardworking and trial-and-error stuff that goes into it. But it's a fun process, and when you finish, you feel like you've accomplished something awesome (cause you have).