Tire Size Calculator

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Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
295/40r21 vs 275/45r21 Tire Comparison Side By Side
  295/40-21 275/45-21 Difference
Diameter inches (mm) 30.29 (769.4) 30.74 (780.9) 0.45 (11.5) 1.5%
Width inches (mm) 11.61 (295) 10.83 (275) -0.79 (-20) -6.8%
Circum. inches (mm) 95.16 (2417.14) 96.59 (2453.27) 1.42 (36.13) 1.5%
Sidewall Height inches (mm) 4.65 (118) 4.87 (123.75) 0.23 (5.75) 4.9%
Revolutions per mile (km) 665.8 (413.71) 656 (407.62) -9.81 (-6.09) -1.5%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.3 mph (32.67 km/h)
25 mph (40.23 km/h)25.37 mph (40.84 km/h)
30 mph (48.28 km/h)30.45 mph (49 km/h)
35 mph (56.33 km/h)35.52 mph (57.17 km/h)
40 mph (64.37 km/h)40.6 mph (65.34 km/h)
45 mph (72.42 km/h)45.67 mph (73.5 km/h)
50 mph (80.47 km/h)50.75 mph (81.67 km/h)
55 mph (88.51 km/h)55.82 mph (89.84 km/h)
60 mph (96.56 km/h)60.9 mph (98 km/h)
65 mph (104.61 km/h)65.97 mph (106.17 km/h)
70 mph (112.65 km/h)71.05 mph (114.34 km/h)
75 mph (120.7 km/h)76.12 mph (122.51 km/h)
80 mph (128.75 km/h)81.2 mph (130.67 km/h)
85 mph (136.79 km/h)86.27 mph (138.84 km/h)
90 mph (144.84 km/h)91.35 mph (147.01 km/h)
95 mph (152.89 km/h)96.42 mph (155.17 km/h)
100 mph (160.93 km/h)101.49 mph (163.34 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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