Does anyone know of a source for the old type "traction" tires. Some people call them snow tires, but they're basically the ones with the zig zag or Z-tread. I've looked on the internet (Coker, Universal, Lucas, etc.) but haven't been able to find anything but your typical "street tread" tire in 20". And what about radials---does anyone know of radials in 6.50x20 or possibly 7.00x20?

Also, it seems like there is a wide variety of tires in 19.5" size--and they're radials, too. I know it's not safe to put a larger tire on a smaller rim (such as a 16.5 tire on a 16 rim), but is it possible to squeeze an old 20" rim into a new 19.5 radial? These are the old multi-piece (not split) rims with the removable lock ring, so I'm thinking they might go on easier than on a one-piece rim. I know of old timers who've done this with a 16 tire on a 16.5 rim, but then again it might not've been a safe setup.

Thanks for the help.