Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
145/70r15 vs 145/65r15 Tire Comparison Side By Side
  145/70-15 145/65-15 Difference
Diameter inches (mm) 22.99 (584) 22.42 (569.5) -0.57 (-14.5) -2.5%
Width inches (mm) 5.71 (145) 5.71 (145) 0 (0) 0%
Circum. inches (mm) 72.23 (1834.69) 70.44 (1789.14) -1.79 (-45.55) -2.5%
Sidewall Height inches (mm) 4 (101.5) 3.71 (94.25) -0.29 (-7.25) -7.1%
Revolutions per mile (km) 877.17 (545.05) 899.51 (558.93) 22.33 (13.88) 2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.5 mph (31.39 km/h)
25 mph (40.23 km/h)24.38 mph (39.23 km/h)
30 mph (48.28 km/h)29.26 mph (47.08 km/h)
35 mph (56.33 km/h)34.13 mph (54.93 km/h)
40 mph (64.37 km/h)39.01 mph (62.78 km/h)
45 mph (72.42 km/h)43.88 mph (70.62 km/h)
50 mph (80.47 km/h)48.76 mph (78.47 km/h)
55 mph (88.51 km/h)53.63 mph (86.32 km/h)
60 mph (96.56 km/h)58.51 mph (94.16 km/h)
65 mph (104.61 km/h)63.39 mph (102.01 km/h)
70 mph (112.65 km/h)68.26 mph (109.86 km/h)
75 mph (120.7 km/h)73.14 mph (117.7 km/h)
80 mph (128.75 km/h)78.01 mph (125.55 km/h)
85 mph (136.79 km/h)82.89 mph (133.4 km/h)
90 mph (144.84 km/h)87.77 mph (141.25 km/h)
95 mph (152.89 km/h)92.64 mph (149.09 km/h)
100 mph (160.93 km/h)97.52 mph (156.94 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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