275/45R21
A 275/45R21 tire is 30.74 inches tall and 10.8 inches wide, with a 4.87-inch sidewall, mounted on a 21-inch wheel.
Common fitments: Cayenne, X5, Range Rover
Overall diameter
30.74″
781 mm
Sidewall height
4.87″
123.8 mm
Tread width
275 mm
10.8″
Circumference
96.59″
8.0 ft
Revs per mile
656
408 per km
Wheel diameter
21″
aspect ratio 45%
Cross-section
- Overall diameter
- 30.74″
- Sidewall (each side)
- 4.87″
- Wheel
- 21″
275/45R21 in inches and millimeters
Every dimension of a 275/45R21, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 30.74″ | 781 mm |
| Tread width | 10.8″ | 275 mm |
| Sidewall height | 4.87″ | 123.8 mm |
| Wheel diameter | 21″ | 533 mm |
| Circumference | 96.59″ | 2453 mm |
Nominal dimensions from the size code. A real tire varies by a few millimeters between manufacturers, and a loaded tire sits slightly shorter than its free diameter.
275/45R21 compared with other sizes
All 24 practical swaps involving 275/45R21 — diameter change, speedometer impact and a fit verdict for each.
275/45R21 → 255/60R19
255/60R19
Diameter −1.0% · This fits
275/45R21 → 265/55R19
265/55R19
Diameter +0.9% · This fits
275/45R21 → 275/55R19
275/55R19
Diameter −0.5% · This fits
275/45R21 → 265/40R21
265/40R21
Diameter +4.8% · Borderline. Check clearance first
275/45R21 → 265/45R21
265/45R21
Diameter +1.2% · This fits
285/45R21 → 275/45R21
285/45R21
Diameter +1.2% · This fits
265/45R21 → 275/45R21
265/45R21
Diameter −1.2% · This fits
275/50R21 → 275/45R21
275/50R21
Diameter +3.5% · Borderline. Check clearance first
285/40R21 → 275/45R21
285/40R21
Diameter −2.5% · This fits
275/40R22 → 275/45R21
275/40R22
Diameter −0.3% · This fits
275/55R19 → 275/45R21
275/55R19
Diameter +0.5% · This fits
265/40R21 → 275/45R21
265/40R21
Diameter −4.5% · Borderline. Check clearance first
285/40R22 → 275/45R21
285/40R22
Diameter +0.8% · This fits
265/55R19 → 275/45R21
265/55R19
Diameter −0.9% · This fits
255/55R20 → 275/45R21
255/55R20
Diameter +1.0% · This fits
255/60R19 → 275/45R21
255/60R19
Diameter +1.0% · This fits
265/50R20 → 275/45R21
265/50R20
Diameter −1.0% · This fits
285/50R20 → 275/45R21
285/50R20
Diameter +1.5% · This fits
275/45R20 → 275/45R21
275/45R20
Diameter −3.3% · Borderline. Check clearance first
275/45R21 → 275/50R21
275/50R21
Diameter −3.4% · Borderline. Check clearance first
275/45R21 → 285/40R21
285/40R21
Diameter +2.6% · This fits
275/45R21 → 285/45R21
285/45R21
Diameter −1.1% · This fits
275/45R21 → 275/40R22
275/40R22
Diameter +0.3% · This fits
275/45R21 → 285/40R22
285/40R22
Diameter −0.7% · This fits
Common questions
- What is 275/45R21 in inches?
- A 275/45R21 tire is 30.74 inches tall and 10.8 inches wide, with a 4.87-inch sidewall, mounted on a 21-inch wheel. In metric that is 781 mm tall and 275 mm wide. The circumference is 96.59 inches.
- How tall is a 275/45R21 tire?
- 30.74 inches, or 781 mm. That is the overall diameter, wheel included. It turns about 656 times per mile, which is what your speedometer counts.
- What do the numbers in 275/45R21 mean?
- 275 is the tread width in millimeters, 45 is the aspect ratio — the sidewall height as a percentage of the tread width — and 21 is the wheel diameter in inches. So the sidewall is 275 × 45% = 123.8 mm tall.