Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
225/50r18 vs 245/45r18 Tire Comparison Side By Side
  225/50-18 245/45-18 Difference
Diameter inches (mm) 26.86 (682.2) 26.68 (677.7) -0.18 (-4.5) -0.7%
Width inches (mm) 8.86 (225) 9.65 (245) 0.79 (20) 8.9%
Circum. inches (mm) 84.38 (2143.19) 83.82 (2129.06) -0.56 (-14.14) -0.7%
Sidewall Height inches (mm) 4.43 (112.5) 4.34 (110.25) -0.09 (-2.25) -2%
Revolutions per mile (km) 750.91 (466.59) 755.9 (469.69) 4.99 (3.1) 0.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.87 mph (31.97 km/h)
25 mph (40.23 km/h)24.84 mph (39.97 km/h)
30 mph (48.28 km/h)29.8 mph (47.96 km/h)
35 mph (56.33 km/h)34.77 mph (55.96 km/h)
40 mph (64.37 km/h)39.74 mph (63.95 km/h)
45 mph (72.42 km/h)44.7 mph (71.94 km/h)
50 mph (80.47 km/h)49.67 mph (79.94 km/h)
55 mph (88.51 km/h)54.64 mph (87.93 km/h)
60 mph (96.56 km/h)59.6 mph (95.92 km/h)
65 mph (104.61 km/h)64.57 mph (103.92 km/h)
70 mph (112.65 km/h)69.54 mph (111.91 km/h)
75 mph (120.7 km/h)74.51 mph (119.9 km/h)
80 mph (128.75 km/h)79.47 mph (127.9 km/h)
85 mph (136.79 km/h)84.44 mph (135.89 km/h)
90 mph (144.84 km/h)89.41 mph (143.89 km/h)
95 mph (152.89 km/h)94.37 mph (151.88 km/h)
100 mph (160.93 km/h)99.34 mph (159.87 km/h)

Gear Ratio / RPMs for New Tire (@ 65 mph)
2.35 2.73 2.94 3.07 3.21 3.31 3.42 3.55 3.73 3.91 4.11 4.27 4.56 4.88 5.13 5.29 5.38 5.71 6.17 7.17
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