From some quick web searching, I'm concluding that these tires no longer exist, at least not in the US or UK. Never was a common size to begin with, being found primarily on early 1970s Volvo wagons. The sedans used the more common 165x15, which also is getting less common, at least in any great range of choice, but 165x15 is still easy to find at good prices from places such as Tirerack.com. Anyway, 165x15 is the original size radial tire for a TR4!