255/40R21 Tires

255/40R21 Conversion

When converted to inches, 255/40R21 is equivalent to 29x10R21.

255/40R21 tire has a section width of 10 inches which is the measurement of tire's width from its inner sidewall to its outer sidewall. Rim diameter of 21 inches represents the size of the wheel the tire can be mounted on. Sidewall height of 4 inches (102 mm) is the measurement from the wheel rim to top of the tire tread. Overall diameter of 29 inches (737 mm) reflects the outer diameter of the tire and stands for tire height. Circumference of 91.1 inches (2314.2 mm) is the outer perimeter of the tire. Tire revolutions indicate the number of times a tire revolves while it covers the distance in miles or kilometers. 255/40R21 tire makes 695 revolutions per mile (432 revolutions per kilometer).

255/40R21 Section Width
10"
29"
255/40R21 Tire Side
Tire Circumference
91.1"
21"
4"
695 Revs/Mile
Metric Inches
Overall Diameter (Tire Height) 737 mm 29"
Tread Width 255 mm 10"
Rim Diameter 533.4 mm 21"
Sidewall Height 102 mm 4"
Circumference 2314.2 mm 91.1"
Revolutions 432 per km 695 per mile

255/40R21 Replacement Tire Sizes

Replacement tires have to be within 3% of the original tire's overall diameter. 255/40R21 tire can be replaced with 30 compatible tire sizes. Select optional plus size to see its specs.

Tire Size Overall Diameter Difference
265/25R23 28.2" (716 mm) -2.8%
305/30R21 28.2" (717 mm) -2.7%
315/25R22 28.2" (717 mm) -2.7%
265/35R21 28.3" (719 mm) -2.4%
265/30R22 28.3" (719 mm) -2.4%
315/30R21 28.5" (723 mm) -1.9%
275/35R21 28.5" (725 mm) -1.6%
275/30R22 28.5" (725 mm) -1.6%
335/25R22 28.6" (727 mm) -1.4%
325/30R21 28.7" (729 mm) -1.1%
245/40R21 28.7" (729 mm) -1.1%
245/35R22 28.8" (731 mm) -0.8%
285/30R22 28.8" (731 mm) -0.8%
285/35R21 28.9" (733 mm) -0.5%
305/25R23 29" (736 mm) -0.1%
255/35R22 29" (737 mm) 0%
295/30R22 29" (737 mm) 0%
295/35R21 29.1" (739 mm) 0.3%
315/25R23 29.2" (742 mm) 0.7%
305/30R22 29.3" (743 mm) 0.8%
235/45R21 29.3" (745 mm) 1.1%
265/40R21 29.3" (745 mm) 1.1%
265/35R22 29.3" (745 mm) 1.1%
305/35R21 29.4" (747 mm) 1.4%
315/30R22 29.5" (749 mm) 1.6%
275/35R22 29.6" (751 mm) 1.9%
315/35R21 29.6" (753 mm) 2.2%
245/45R21 29.6" (753 mm) 2.2%
275/40R21 29.6" (753 mm) 2.2%
285/35R22 29.9" (759 mm) 3%