Spring-Steel Wheels (2018):

The University Rover Challenge rules state the rover should be able to climb rough terrain and survive drops of up to 1 meter, but give no further detail on the requirements.
In past years, we used conventional inflatable rubber tires which suffered issues with grip in deep sand and shock absorption, and we could never find wheels that fit our exact specifications.
I designed a wheel made from blue spring steel shim stock that acted as a spring and could have custom flexible 3d printed or molded rubber treads bolted to its outer surface.
Based on the steel's thickness, the wheel-spring stiffness could be tuned exactly to our rover.
The paddle-treads I designed were useful for the deep sand that the rover previously got stuck in.
As an added benefit, these wheels' structure allowed them to be exceptionally lightweight yet rigid.