Tire Size Calculator

Tire Size Finder (optional):

Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
235/50r18 vs 245/40r20 Tire Comparison Side By Side
  235/50-18 245/40-20 Difference
Diameter inches (mm) 27.25 (692.2) 27.72 (704) 0.46 (11.8) 1.7%
Width inches (mm) 9.25 (235) 9.65 (245) 0.39 (10) 4.3%
Circum. inches (mm) 85.61 (2174.61) 87.07 (2211.68) 1.46 (37.07) 1.7%
Sidewall Height inches (mm) 4.63 (117.5) 3.86 (98) -0.77 (-19.5) -16.6%
Revolutions per mile (km) 740.06 (459.85) 727.66 (452.14) -12.4 (-7.71) -1.7%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.34 mph (32.74 km/h)
25 mph (40.23 km/h)25.43 mph (40.92 km/h)
30 mph (48.28 km/h)30.51 mph (49.1 km/h)
35 mph (56.33 km/h)35.6 mph (57.29 km/h)
40 mph (64.37 km/h)40.68 mph (65.47 km/h)
45 mph (72.42 km/h)45.77 mph (73.66 km/h)
50 mph (80.47 km/h)50.85 mph (81.84 km/h)
55 mph (88.51 km/h)55.94 mph (90.02 km/h)
60 mph (96.56 km/h)61.02 mph (98.21 km/h)
65 mph (104.61 km/h)66.11 mph (106.39 km/h)
70 mph (112.65 km/h)71.19 mph (114.57 km/h)
75 mph (120.7 km/h)76.28 mph (122.76 km/h)
80 mph (128.75 km/h)81.36 mph (130.94 km/h)
85 mph (136.79 km/h)86.45 mph (139.13 km/h)
90 mph (144.84 km/h)91.53 mph (147.31 km/h)
95 mph (152.89 km/h)96.62 mph (155.49 km/h)
100 mph (160.93 km/h)101.7 mph (163.68 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
18522151231724192529260826952797293930813239336535933845404241684239449948625650
Better Fuel Economy Factory Ratios Increased Power

Most Popular 235/50-R18 Comparisons

To Top