Based on my research, the majority of beetle-weight battlebots seem to have success with "lite-flite" wheels. I believe these were originally intended for model airplanes, but they have been used by a number of successful bots. Additionally, FingerTech Robotics make an excellent snap-hub that fits them and provides a secure connection. The wheels are a light-weight, resilient, and sticky rubber foam which seems to absorb major hits excellently. I decided to use these wheels and snap-hubs on my robot. Unfortunately, I discovered an interesting issue.
When my robot got up to speed and then tried to turn, the side load on the wheel would cause the wheel to deform underneath the edge of my robot, where it would become stuck. This could completely immobilize my robot. Unfortunately I couldn't get a good photo of this phenomenon, but I hope this diagram makes sense:
When my robot got up to speed and then tried to turn, the side load on the wheel would cause the wheel to deform underneath the edge of my robot, where it would become stuck. This could completely immobilize my robot. Unfortunately I couldn't get a good photo of this phenomenon, but I hope this diagram makes sense:
The fix to this turned out to be relatively easy. I fabricated some wheel stiffeners out of some 1/8" poly-carbonate and placed them inboard of the wheels. They worked great at resolving the pinching problem. I'm waiting to see if they start causing other issues thou. You can see them in this photo of the partially assembled bot: