315/40R21 Tires
315/40R21 Conversion
When converted to inches, 315/40R21 is equivalent to 30.9x12.4R21.
315/40R21 tire has a section width of 12.4 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 5 inches (126 mm) is the measurement from the wheel rim to top of the tire tread. Overall diameter of 30.9 inches (785 mm) reflects the outer diameter of the tire and stands for tire height. Circumference of 97 inches (2464.9 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. 315/40R21 tire makes 653 revolutions per mile (406 revolutions per kilometer).
| Metric | Inches | |
|---|---|---|
| Overall Diameter (Tire Height) | 785 mm | 30.9" |
| Tread Width | 315 mm | 12.4" |
| Rim Diameter | 533.4 mm | 21" |
| Sidewall Height | 126 mm | 5" |
| Circumference | 2464.9 mm | 97" |
| Revolutions | 406 per km | 653 per mile |
| Best Prices on 315/40R21 Tires | |
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 from $327.50 |
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 from $407.91 |
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 from $327.50 |
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315/40R21 Replacement Tire Sizes
Replacement tires have to be within 3% of the original tire's overall diameter. 315/40R21 tire can be replaced with 26 compatible tire sizes. Select optional plus size to see its specs.
| Tire Size | Overall Diameter | Difference |
|---|---|---|
| 295/30R23 | 30" (762 mm) | -2.9% |
| 255/40R22 | 30" (763 mm) | -2.8% |
| 255/45R21 | 30" (763 mm) | -2.8% |
| 295/35R22 | 30.1" (765 mm) | -2.5% |
| 295/40R21 | 30.3" (769 mm) | -2% |
| 265/40R22 | 30.4" (771 mm) | -1.8% |
| 265/45R21 | 30.4" (771 mm) | -1.8% |
| 305/35R22 | 30.4" (773 mm) | -1.5% |
| 275/40R22 | 30.7" (779 mm) | -0.8% |
| 315/35R22 | 30.7" (779 mm) | -0.8% |
| 325/30R23 | 30.7" (780 mm) | -0.6% |
| 275/45R21 | 30.7" (781 mm) | -0.5% |
| 285/35R23 | 30.9" (784 mm) | -0.1% |
| 285/40R22 | 31" (787 mm) | 0.3% |
| 325/35R22 | 31" (787 mm) | 0.3% |
| 285/45R21 | 31.1" (789 mm) | 0.5% |
| 255/45R22 | 31.1" (789 mm) | 0.5% |
| 255/50R21 | 31.1" (789 mm) | 0.5% |
| 295/35R23 | 31.1" (790 mm) | 0.6% |
| 325/40R21 | 31.2" (793 mm) | 1% |
| 295/40R22 | 31.3" (795 mm) | 1.3% |
| 265/45R22 | 31.4" (797 mm) | 1.5% |
| 305/35R23 | 31.4" (798 mm) | 1.7% |
| 305/40R22 | 31.6" (803 mm) | 2.3% |
| 275/40R23 | 31.7" (804 mm) | 2.4% |
| 275/45R22 | 31.8" (807 mm) | 2.8% |