275/45R21 in inches
A 275/45R21 tire stands 30.7 inches tall and is 10.8 inches wide. It fits a 21-inch wheel. People usually call it a 31-inch tire.
Tall
30.7″
781 mm
Wide
10.8″
275 mm
Wheel
21″
rim diameter
Cars that come with 275/45R21
Similar-height sizes
Within 3% of 275/45R21, so your speedometer stays close.
| Size | Height | vs 275/45R21 | |
|---|---|---|---|
| 265/70R16 | 30.6″ | −0.4%needs 16″ wheels | Compare |
| 265/65R17 | 30.6″ | −0.6%needs 17″ wheels | Compare |
| 265/60R18 | 30.5″ | −0.7%needs 18″ wheels | Compare |
| 245/70R17 | 30.5″ | −0.8%needs 17″ wheels | Compare |
| 245/75R16 | 30.5″ | −0.9%needs 16″ wheels | Compare |
| 295/45R20 | 30.5″ | −0.9%needs 20″ wheels | Compare |
| 255/55R20 | 31.0″ | +1.0%needs 20″ wheels | Compare |
| 255/65R18 | 31.1″ | +1.0%needs 18″ wheels | Compare |
How 275/45R21 is measured
| Measurement | Inches | Millimetres |
|---|---|---|
| Overall height (diameter) | 30.74 | 781 |
| Tread width | 10.83 | 275 |
| Sidewall height | 4.87 | 124 |
| Distance per turn (circumference) | 96.6 | 2453 |
| Turns per mile | 656 | |
The first number (275) is the width in millimetres. The second (45) means the sidewall is 45% as tall as the tire is wide. The last (21) is the wheel size in inches. More on reading a tire size.