@phil klopp posted:I have just reviewed posts on this forum regarding traction tires. I have an accumulation of various tires from engines of all the manufacturers and wonder how much differences small diameter differences make in choosing replacements. Frequently the suggested tire for a particular engine is not available and I have installed a close match that is usually a little smaller and needs more stretching to get it on. Sometimes I think the wrong tire, stretched to fit even lasts longer but this is just a hunch. Some tires I own of similar diameter are much thicker rubber and allow for more stretching. The question comes down to whether traction tires work best if they are stretched and tight or thicker and looser. I realize the answer to this question is complicated and would involve tracking engine running times and how long tires last in some of the above mentioned circumstances. Other thoughts on this matter would be appreciated. Phil
IMHO, the biggest problem with traction tires is that the thermoset rubber compound is too soft and "sticky." I believe the compound is thermoset neoprene rubber with a Shore A hardness of about 20-30, about that of a rubber band. It would seem to me that the same rubber used in car & truck tires, thermoset natural rubber (or even thermoset EPDM rubber) at Shore A 70-80 hardness would perform much better and last longer. With the harder rubber you would get a little "slip" when you needed it around tight turns yet plenty of traction with a fairly heavy loco and, like the treadwear ratings on car tires show, more resistance to cutting and abrasion as the hardness goes up. I worked at Advanced Elastomer Systems making Santoprene, which is a thermoplastic elastomer, that would also function well in this application at the same hardness and be easier to fabricate as it could be extruded into tubes of the appropriate diameter and wall thickness and cut to width on an appropriate mandrel. Trouble is, all of this stuff is made in China now (nothing against the Chinese people) at the lowest possible cost and car tire rubber is likely too expensive in their "cost model."
