[BBray_T1296]

Originally Posted by PowerfulKitty

Shock absorption: Seems to be the greatest benefit of pneumatic wheels. That said, I don't see how the impact of crossing defenses is going to be any more violent than the full court ramming that robots survived in 2014. Therefore I believe that the electrical and mechanical parts of the robot should handle it just fine.

2014's collisions were bumper-to-bumper impacts. The bumpers allow the kinetic energy to exchange a little bit slower than instantaneously, reducing the impulse experienced by the robot. In addition, the bumpers were usually mounted to the main frame of the robot, which can direct forces throughout the robot in a uniform way.

When crossing defenses, it is your wheels that take the brunt of that force. A pneumatic tire acts like the bumpers do and reduces the impulse delivered to the robot, namely the axle. A hard wheel will shunt the full impacting force all at once into a shear impulse against the axle and its bearings, which could shatter bearings, or shear the whole wheel off.

In our testing, we build a chain driven west coast drive using VexPro versablocks, and due to the specific configuration could only get 2 bolts to hold it clamped to the frame tube. We put VexPro traction wheels on it and sent it at the defenses. After just a few crossings at decent speeds the chains had all fallen off. The impacts of the wheels colliding with namely the Rock Wall had moved each versablock more than 1/8" closer to the center until the chains got too loose. Obviously this was a problem specific to our configuration but I would not expect such a thing to have happened with pneumatic wheels.