I pulled some of the dimensional info out of Goodyear's Marathon brochure, and copied it below. Actually, this was mostly an experiment in formatting a post. Can everyone see it OK?
Since the tire "Diameter" is not simply twice the "Loaded Radius", I assume that "Diameter" means the overall diameter of the unloaded tire, while "Loaded radius" means the distance from the center of the axle to the ground when the tire is carrying a load. I would also assume that the distance from the center of the axle to the top of the loaded tire would be half the "Diameter". WMTIRE, can you confirm or correct all this?
The first line is the 14" tire that TM puts on most of our TMs.
The second line is the 15" load range C tire.
The third line is the 15" load range D tire.
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Tire................Load....Tire...Outside.....Loaded ..Max
Size...............Range..Width.Diameter...Radius.....Load
ST215/75R14.....C.......8.5.....26.6.......12.4....1870@50psi
ST225/75R15.....C.......8.7.....28.3.......13.0....2150@50psi
ST225/75R15.....D.......8.7.....28.3.......13.0....2540@65psi
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All tires are rated for 65 mph
Bill
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