Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
120/85r18 vs 110/90r18 Tire Comparison Side By Side
  120/85-18 110/90-18 Difference
Diameter inches (mm) 26.03 (661.2) 25.8 (655.2) -0.24 (-6) -0.9%
Width inches (mm) 4.72 (120) 4.33 (110) -0.39 (-10) -8.3%
Circum. inches (mm) 81.78 (2077.22) 81.04 (2058.37) -0.74 (-18.85) -0.9%
Sidewall Height inches (mm) 4.02 (102) 3.9 (99) -0.12 (-3) -2.9%
Revolutions per mile (km) 774.76 (481.41) 781.85 (485.82) 7.09 (4.41) 0.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.82 mph (31.89 km/h)
25 mph (40.23 km/h)24.77 mph (39.87 km/h)
30 mph (48.28 km/h)29.73 mph (47.84 km/h)
35 mph (56.33 km/h)34.68 mph (55.82 km/h)
40 mph (64.37 km/h)39.64 mph (63.79 km/h)
45 mph (72.42 km/h)44.59 mph (71.76 km/h)
50 mph (80.47 km/h)49.55 mph (79.74 km/h)
55 mph (88.51 km/h)54.5 mph (87.71 km/h)
60 mph (96.56 km/h)59.46 mph (95.68 km/h)
65 mph (104.61 km/h)64.41 mph (103.66 km/h)
70 mph (112.65 km/h)69.36 mph (111.63 km/h)
75 mph (120.7 km/h)74.32 mph (119.61 km/h)
80 mph (128.75 km/h)79.27 mph (127.58 km/h)
85 mph (136.79 km/h)84.23 mph (135.55 km/h)
90 mph (144.84 km/h)89.18 mph (143.53 km/h)
95 mph (152.89 km/h)94.14 mph (151.5 km/h)
100 mph (160.93 km/h)99.09 mph (159.47 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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