<VV> Tire gurus - What kind of tires do I have?

[Steve Oxford]

The tires were marked:
Front: P185/80D-13

Just to clear things up, the "D" stands for "D" load range.  Those bias ply tires are actually fairly common today, and may be relatively new, since Doug thought they looked in good condition.   They are used for trailers, and are normally marked as such, and not for passenger car use.  Someone else suggested the "D" stood for "diagonal" - not so.  I don't know that those tires are inherently insafe for use on passenger cars, but they definitely would have all of the negative aspects of the old bias ply tires that we all loved to hate.  Remember how the old nylon tires flat spotted if the car sat too long or the weather got cold?  Thump, thump, thump until they warmed up.

As Matt suggested, the C or D 78 tires are either bias ply or belted tires from the 70s, since that designation has not been used since then.  Those tires, regardless of how good they look, are probably dangerous.  

Steve Oxford/'63 conv, w/radials