We have a small stash of vintage Precision Miniatures 1/43 scale tires available. These were highly regarded for being quite accurate and appropriate for 1950's and early 1960's sports and competition model cars like the Porsche 550 spyder or the Ferrari 250 Testa Rossa.
The tires are vintage and a little firm, but still pliable. A quick soak in hot water will allow them to fit most any wheel.