Well thanks very much flyboy,I had been doing a lot of looking here and there and have seen a pic of a P51 with what I took to be a similar style wheel.
Apologies to everyone for not thanking you for allowing me the place to post such a question,I like the site a lot.Also sorry for putting such a biggggg picture on,anyone not on broadband would have to wait an age to download it
Going back to the wheel,was it likely that the same type were fitted to several different fighter types(American)??
The tyre is indeed a C27 Firestone Sky Champion ,made in Canada.