Today, I learned that RC tank battles are not only a thing, they are serious business.
Really, I’d love to see someone do this. Based on that site, it looks like roller chain would be a good bet, assuming the rules allow it (I can’t remember any chain- or sprocket- specific rules, but perhaps maybe something about drive surfaces?).
[R06]
Traction devices may not have surface features such as metal, sandpaper, hard plastic studs, cleats, or other attachments. Traction devices include all parts of the Robot that are designed to transmit any propulsive and/or braking forces between the Robot and the Court.