Well.....
Last year we experimented with gum rubber. MMMMM I lub that stuff.
As some or many may know, we cut out roughly 8" circles of 1" gum, and then cut the middle out of them to make it lighter in the final design. We then took 2, 1" thick gum rubber circles (cut out with hole saws) and sandwiched them in 3 pieces of 1/8" aluminum and secured them tightly together with screws. EW also made hubs to attch sprockets to, out of round stock aluminum 3" I think. We ended up with 4 wheels that had 2 gum rubber cuts in side. 8 traction points. The wheels were, dually's if you will. The gripped like mad. We still can boast no person can puch or robot. We haven't tested on other bots cep for matches and stack guarding (we would tip over before these wheels would slide, (we didn't tip)). They were nice. I rember one match in a mini were 341 (Daisy) tried to take down our 4 stack. They ended up pounding away at us and bending 1/8" physical limits for our arm, but the stack stood. Their drivers were persistent, and would not give up. That was a fun match
.
Man I love those wheels. And I think, if memory serves, we won the KOH (king of the hill) contest at Ramp Riot. Because of their traction on the ice.
They wieghed about 8 lbs each though. We will find a way to get them back, and underweight if need be, I am sure of it. mwahahahaha.
-Henry