Re: suspension

Toy rubber balls make excellent elastomer suspension. The superballs are too hard, but with the right amount of squish they actually damp chatter very well and have a built in rising spring rate so large bumps are resisted with appropriate force.

For more advanced damping, the gas-charged struts used for hatchbacks work very well on the rebound and can be had with almost the right gas pressure.

:)ensen.