Jeep 2005 Wrangler Owner's Manual page 208

208 STARTING AND OPERATING
Tire Sizing Chart
Size Designation:
P = Passenger car tire size based on U.S. design standards
....blank.... = Passenger car tire based on European design standards
LT = Light Truck tire based on U.S. design standards
T = Temporary Spare tire
31 = Overall Diameter in Inches (in)
215 = Section Width in Milimeters (mm)
65 = Aspect Ratio in Percent (%)
10.5 = Section Width in Inches (in)
R = Construction Code
15 = Rim Diameter in Inches (in)
—Ratio of section height to section width of tire.
— R means Radial Construction.
— D means Diagonal or Bias Construction.
EXAMPLE: