Tire Size Calculator

Tire Size Finder (optional):

Stock Sizes

  • 255/75-16

Plus Sizes

  • 255/75-16

Accepts P-Metric and Inches
/ R
/ R
325/25r21 vs 265/35r20 Tire Comparison Side By Side
  325/25-21 265/35-20 Difference
Diameter inches (mm) 27.4 (695.9) 27.3 (693.5) -0.09 (-2.4) -0.3%
Width inches (mm) 12.8 (325) 10.43 (265) -2.36 (-60) -18.5%
Circum. inches (mm) 86.07 (2186.23) 85.78 (2178.69) -0.3 (-7.54) -0.3%
Sidewall Height inches (mm) 3.2 (81.25) 3.65 (92.75) 0.45 (11.5) 14.2%
Revolutions per mile (km) 736.13 (457.41) 738.67 (458.99) 2.55 (1.58) 0.3%

Speedometer Difference

Speedo Reading Actual Speed
20 mph (32.19 km/h)19.93 mph (32.08 km/h)
25 mph (40.23 km/h)24.91 mph (40.09 km/h)
30 mph (48.28 km/h)29.9 mph (48.11 km/h)
35 mph (56.33 km/h)34.88 mph (56.13 km/h)
40 mph (64.37 km/h)39.86 mph (64.15 km/h)
45 mph (72.42 km/h)44.84 mph (72.17 km/h)
50 mph (80.47 km/h)49.83 mph (80.19 km/h)
55 mph (88.51 km/h)54.81 mph (88.21 km/h)
60 mph (96.56 km/h)59.79 mph (96.23 km/h)
65 mph (104.61 km/h)64.78 mph (104.25 km/h)
70 mph (112.65 km/h)69.76 mph (112.27 km/h)
75 mph (120.7 km/h)74.74 mph (120.28 km/h)
80 mph (128.75 km/h)79.72 mph (128.3 km/h)
85 mph (136.79 km/h)84.71 mph (136.32 km/h)
90 mph (144.84 km/h)89.69 mph (144.34 km/h)
95 mph (152.89 km/h)94.67 mph (152.36 km/h)
100 mph (160.93 km/h)99.66 mph (160.38 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
18802184235224562568264827362840298431283288341636483904410442324304456749355735
Better Fuel Economy Factory Ratios Increased Power

Most Popular 325/25-R21 Comparisons

To Top