Further to Roger Schaaf comments about coker tires, I' d like to share my experience with these tires. I bought 5 coker tires radial 235 /75 X15 www for my 300B and I have to agree with Roger concerning the difficulty to correctly balance these tires.The tire shop had to put so many weights on one of my wheels that I had to use it as the spare wheel. I drove this car quite hard on every kind of roads , I went on narrow french mountain roads with many sharp bends and I even drove this car on a race track (not slowly) and to my great surprise I'm very satisfied with these tires. They perform pretty well. I've never tried Michelin tires with vintage cars and I think they don't supply www for our cars, but even though they could be of better quality than Coker tires you could still get 4 Coker tires for the price of 1 Michelin.So I think Coker radial tires are good alternative for 50 American cars.I don't know about Diamond black. Raphael Brunet ,Paris France