RedDevil -- I have high hopes for your thread. I'm back where I can copy/paste and type with more than one finger.
The article I'd looked at is:
<<
Tires: Urethane v. Silicone>>
It talks about polyurethane's problem, traction. It's an undated article, but states a farm implement tire was introduced that May. It also mentions organosilanes.
The first I ever heard about polyurethane tires was in an article in Popular Mechanix Illustrated some years ago. It played up the low capital investment and said manufacturing would be local on the scale of a re-capping shop and they'd make your tires on demand.