Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
175/70r12 vs 135/80r15 Tire Comparison Side By Side
  175/70-12 135/80-15 Difference
Diameter inches (mm) 21.65 (549.8) 23.5 (597) 1.86 (47.2) 8.6%
Width inches (mm) 6.89 (175) 5.31 (135) -1.57 (-40) -22.9%
Circum. inches (mm) 68 (1727.25) 73.84 (1875.53) 5.84 (148.28) 8.6%
Sidewall Height inches (mm) 4.82 (122.5) 4.25 (108) -0.57 (-14.5) -11.8%
Revolutions per mile (km) 931.74 (578.95) 858.07 (533.18) -73.67 (-45.77) -7.9%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)21.72 mph (34.95 km/h)
25 mph (40.23 km/h)27.15 mph (43.69 km/h)
30 mph (48.28 km/h)32.58 mph (52.43 km/h)
35 mph (56.33 km/h)38 mph (61.16 km/h)
40 mph (64.37 km/h)43.43 mph (69.9 km/h)
45 mph (72.42 km/h)48.86 mph (78.64 km/h)
50 mph (80.47 km/h)54.29 mph (87.38 km/h)
55 mph (88.51 km/h)59.72 mph (96.11 km/h)
60 mph (96.56 km/h)65.15 mph (104.85 km/h)
65 mph (104.61 km/h)70.58 mph (113.59 km/h)
70 mph (112.65 km/h)76.01 mph (122.33 km/h)
75 mph (120.7 km/h)81.44 mph (131.06 km/h)
80 mph (128.75 km/h)86.87 mph (139.8 km/h)
85 mph (136.79 km/h)92.3 mph (148.54 km/h)
90 mph (144.84 km/h)97.73 mph (157.28 km/h)
95 mph (152.89 km/h)103.16 mph (166.01 km/h)
100 mph (160.93 km/h)108.58 mph (174.75 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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