Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
115/70r15 vs 125/70r15 Tire Comparison Side By Side
  115/70-15 125/70-15 Difference
Diameter inches (mm) 21.34 (542) 21.89 (556) 0.55 (14) 2.6%
Width inches (mm) 4.53 (115) 4.92 (125) 0.39 (10) 8.7%
Circum. inches (mm) 67.04 (1702.74) 68.77 (1746.73) 1.73 (43.98) 2.6%
Sidewall Height inches (mm) 3.17 (80.5) 3.44 (87.5) 0.28 (7) 8.7%
Revolutions per mile (km) 945.15 (587.29) 921.35 (572.5) -23.8 (-14.79) -2.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.52 mph (33.02 km/h)
25 mph (40.23 km/h)25.65 mph (41.27 km/h)
30 mph (48.28 km/h)30.77 mph (49.53 km/h)
35 mph (56.33 km/h)35.9 mph (57.78 km/h)
40 mph (64.37 km/h)41.03 mph (66.04 km/h)
45 mph (72.42 km/h)46.16 mph (74.29 km/h)
50 mph (80.47 km/h)51.29 mph (82.55 km/h)
55 mph (88.51 km/h)56.42 mph (90.8 km/h)
60 mph (96.56 km/h)61.55 mph (99.06 km/h)
65 mph (104.61 km/h)66.68 mph (107.31 km/h)
70 mph (112.65 km/h)71.81 mph (115.56 km/h)
75 mph (120.7 km/h)76.94 mph (123.82 km/h)
80 mph (128.75 km/h)82.07 mph (132.07 km/h)
85 mph (136.79 km/h)87.2 mph (140.33 km/h)
90 mph (144.84 km/h)92.32 mph (148.58 km/h)
95 mph (152.89 km/h)97.45 mph (156.84 km/h)
100 mph (160.93 km/h)102.58 mph (165.09 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
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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