I read through the extensive archive about tire choice and checked the websites of various vendors here in the U.S. for Dunlop RS5 (6.40x15) alternatives. Can someone tell me where to buy tires with that format? So far I could only find a Firestone tire of that size. I am replacing my set of Dunlop RS5 on my '63 OTS for age reason and I would like to maintain the original visual appearance. I am aware of the 185x15 alternatives but I prefer the cross-plus. Any recommendation is much appreciated.