The Ebay place that I found selling them, states they were designed 50 years ago for bias ply, but they seem to work ok on 75 series tires.. but at $60 a set, I'm not going to buy them if I can't make them work... guess I gotta get some rubber paint... the new tires I have are LT series tires, but there the same diamater, just a 1/2" narrower.. I want to roll with the '51 this year, but I can't afford over $400 for new Coker wide whites now, and I don't think the black walls will look good