Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
125/70r17 vs 235/40r18 Tire Comparison Side By Side
  125/70-17 235/40-18 Difference
Diameter inches (mm) 23.89 (606.8) 25.4 (645.2) 1.51 (38.4) 6.3%
Width inches (mm) 4.92 (125) 9.25 (235) 4.33 (110) 88%
Circum. inches (mm) 75.05 (1906.32) 79.8 (2026.96) 4.75 (120.64) 6.3%
Sidewall Height inches (mm) 3.44 (87.5) 3.7 (94) 0.26 (6.5) 7.4%
Revolutions per mile (km) 844.22 (524.57) 793.97 (493.35) -50.24 (-31.22) -6%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.27 mph (34.22 km/h)
25 mph (40.23 km/h)26.58 mph (42.78 km/h)
30 mph (48.28 km/h)31.9 mph (51.34 km/h)
35 mph (56.33 km/h)37.21 mph (59.89 km/h)
40 mph (64.37 km/h)42.53 mph (68.45 km/h)
45 mph (72.42 km/h)47.85 mph (77 km/h)
50 mph (80.47 km/h)53.16 mph (85.56 km/h)
55 mph (88.51 km/h)58.48 mph (94.12 km/h)
60 mph (96.56 km/h)63.8 mph (102.67 km/h)
65 mph (104.61 km/h)69.11 mph (111.23 km/h)
70 mph (112.65 km/h)74.43 mph (119.78 km/h)
75 mph (120.7 km/h)79.75 mph (128.34 km/h)
80 mph (128.75 km/h)85.06 mph (136.9 km/h)
85 mph (136.79 km/h)90.38 mph (145.45 km/h)
90 mph (144.84 km/h)95.7 mph (154.01 km/h)
95 mph (152.89 km/h)101.01 mph (162.56 km/h)
100 mph (160.93 km/h)106.33 mph (171.12 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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