I have some clear vinyl traction tires for HO locomotives, and they seem more resistant to oils and whatever else causes them to deteriorate, holding up better than my O27 handcar tires. And I have seen some insulation on wires get hard or gummy due to oils, etc., but I have a few scraps of 60 year old Marx wire that seem to be resistant to everything, oil, solvents, and time. I think they could make an almost life-long traction tire if it were important to the manufacturers. It has to be something in the formulation of the rubbery substance that makes them more or less vulnerable.
Bet some old-school DuPont chemists would know what's going on. Perhaps a contaminate in the mix is the culprit. At about $1.50 for an O27 handcar tire, I am looking for a substitute. Those little rubber bands that the craft stores sell are working for me now, and I found them in black recently at Hobby Lobby. They are similar to the rubber bands for women's hair the Dollar Tree used to have. Sometimes 2 together fills the grove, side by side, and they are of varying diameters.
