The very common big Dinky Toys 20mm Black (block) treaded tyre , covering a major period during the 1950s and 1960s.
Originally packed in a dozen box, with the catalogue number 10253, it was very useful to have available as a spare tyre. Common for the majority of 1:48 scale Dinky Supertoys like the Fodens. In the early period it was parallelled by the Grey 20mm tyre with round tread, which changed into a Grey block tread in 1957/58.
In ca. 1953 this tyre succeeded the one with round tread, which was in use since ca. 1949, and which succeeded the one with ‘herringbone’ tread, which was in use on the prewar racing cars since 1936 already, and continued to be used on the early Fodens of 1947 (and the early Large Trailers and the early Bedford Articulated Lorries of 1948)
As a reference the spare tyres as demonstrated in the 1961 British catalogue, showing both old and new numbers.