Anonymous wrote:would a kart then have zero unsprung mass?
Fiendish question - engineers had better answer this!
My GUESS
If any structure flexes (all do to some extent), then the structure is a very limited spring. So, perhaps yes, even karts have unsprung mass.
I would imagine that it is far less critical than when you have suspension systems that are intended to allow the wheels to move relative to the chassis. So I guess that it is way down the list of priorities when thinking about designing a kart (although rotating mass of the wheels is probably much higher up

).