Originally Posted by SlowerOne

Gadget - it doesn't matter how many types of rubber you try, the mechanics of how the different tyres behave remains the same.

A rubber tyre is a homogenous construction where there is a single contact patch acting on the sidewalls. Once the grip is overcome (static friction) the patch snaps to the straight ahead and the speed has to come right off (sliding friction is less than static friction) to restore the static friction. No matter what construction you have (air filled, foam filled, insert filled) the tyre will generate side grip by the angle of the contact patch relative to the sidewalls.

A foam tyre is heterogeneous in that it is not of uniform composition. Each cell of the rubber is flexibly connected to the next one. When one area of the tyre loses grip it snaps straight ahead, but the bit it is connected to doesn't as the connection is flexible. That characteristic allows the tyre to have some parts with grip, and some without, leading to a progressive slide that is easy to control and, in effect, never completely losing grip.

Almost every type and compound of rubber has been tried with the same effect - pan cars are nasty to drive on rubber! please don't let me stop you having another go, but please also forgive me if I don't hold my breath!!

Good luck...