Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
265/40r21 vs 275/35r21 Tire Comparison Side By Side
  265/40-21 275/35-21 Difference
Diameter inches (mm) 29.35 (745.4) 28.58 (725.9) -0.77 (-19.5) -2.6%
Width inches (mm) 10.43 (265) 10.83 (275) 0.39 (10) 3.8%
Circum. inches (mm) 92.19 (2341.74) 89.78 (2280.48) -2.41 (-61.26) -2.6%
Sidewall Height inches (mm) 4.17 (106) 3.79 (96.25) -0.38 (-9.75) -9.2%
Revolutions per mile (km) 687.24 (427.03) 705.7 (438.5) 18.46 (11.47) 2.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.48 mph (31.34 km/h)
25 mph (40.23 km/h)24.35 mph (39.18 km/h)
30 mph (48.28 km/h)29.22 mph (47.02 km/h)
35 mph (56.33 km/h)34.08 mph (54.85 km/h)
40 mph (64.37 km/h)38.95 mph (62.69 km/h)
45 mph (72.42 km/h)43.82 mph (70.53 km/h)
50 mph (80.47 km/h)48.69 mph (78.36 km/h)
55 mph (88.51 km/h)53.56 mph (86.2 km/h)
60 mph (96.56 km/h)58.43 mph (94.03 km/h)
65 mph (104.61 km/h)63.3 mph (101.87 km/h)
70 mph (112.65 km/h)68.17 mph (109.71 km/h)
75 mph (120.7 km/h)73.04 mph (117.54 km/h)
80 mph (128.75 km/h)77.91 mph (125.38 km/h)
85 mph (136.79 km/h)82.78 mph (133.22 km/h)
90 mph (144.84 km/h)87.65 mph (141.05 km/h)
95 mph (152.89 km/h)92.51 mph (148.89 km/h)
100 mph (160.93 km/h)97.38 mph (156.72 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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