RAM 2500 2021 Owner's Manual page 452

450 SERVICING AND MAINTENANCE
LT = Light truck tire based on US design standards, or
T or S = Temporary spare tire or
31 = Overall diameter in inches (in)
215, 235, 145 = Section width in millimeters (mm)
65, 85, 80 = Aspect ratio in percent (%)
Ratio of section height to section width of tire, or
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10.5 = Section width in inches (in)
R = Construction code
"R" means radial construction, or
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"D" means diagonal or bias construction
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15, 16, 18 = Rim diameter in inches (in)
Service Description:
95 = Load Index
A numerical code associated with the maximum load a tire can carry

H = Speed Symbol
A symbol indicating the range of speeds at which a tire can carry a load corresponding to its load index under certain operating conditions
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The maximum speed corresponding to the speed symbol should only be achieved under specified operating conditions (i.e., tire pressure, vehicle

loading, road conditions, and posted speed limits)
EXAMPLE: