Tire Size Calculator

Tire Size Finder (optional):

Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
80/100r21 vs 90/90r21 Tire Comparison Side By Side
  80/100-21 90/90-21 Difference
Diameter inches (mm) 27.3 (693.4) 27.38 (695.4) 0.08 (2) 0.3%
Width inches (mm) 3.15 (80) 3.54 (90) 0.39 (10) 12.5%
Circum. inches (mm) 85.76 (2178.38) 86.01 (2184.66) 0.25 (6.28) 0.3%
Sidewall Height inches (mm) 3.15 (80) 3.19 (81) 0.04 (1) 1.3%
Revolutions per mile (km) 738.78 (459.06) 736.66 (457.74) -2.12 (-1.32) -0.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)20.06 mph (32.28 km/h)
25 mph (40.23 km/h)25.07 mph (40.35 km/h)
30 mph (48.28 km/h)30.09 mph (48.42 km/h)
35 mph (56.33 km/h)35.1 mph (56.49 km/h)
40 mph (64.37 km/h)40.12 mph (64.56 km/h)
45 mph (72.42 km/h)45.13 mph (72.63 km/h)
50 mph (80.47 km/h)50.14 mph (80.7 km/h)
55 mph (88.51 km/h)55.16 mph (88.77 km/h)
60 mph (96.56 km/h)60.17 mph (96.84 km/h)
65 mph (104.61 km/h)65.19 mph (104.91 km/h)
70 mph (112.65 km/h)70.2 mph (112.98 km/h)
75 mph (120.7 km/h)75.22 mph (121.05 km/h)
80 mph (128.75 km/h)80.23 mph (129.12 km/h)
85 mph (136.79 km/h)85.25 mph (137.19 km/h)
90 mph (144.84 km/h)90.26 mph (145.26 km/h)
95 mph (152.89 km/h)95.27 mph (153.33 km/h)
100 mph (160.93 km/h)100.29 mph (161.4 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
18752178234524492561264027282832297631193279340636383893409242204292455549225720
Better Fuel Economy Factory Ratios Increased Power

Most Popular 80/100-R21 Comparisons

To Top