265/40R21
A 265/40R21 tire is 29.35 inches tall and 10.4 inches wide, with a 4.17-inch sidewall, mounted on a 21-inch wheel.
Overall diameter
29.35″
745 mm
Sidewall height
4.17″
106.0 mm
Tread width
265 mm
10.4″
Circumference
92.19″
7.7 ft
Revs per mile
687
427 per km
Wheel diameter
21″
aspect ratio 40%
Cross-section
- Overall diameter
- 29.35″
- Sidewall (each side)
- 4.17″
- Wheel
- 21″
265/40R21 in inches and millimeters
Every dimension of a 265/40R21, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 29.35″ | 745 mm |
| Tread width | 10.4″ | 265 mm |
| Sidewall height | 4.17″ | 106.0 mm |
| Wheel diameter | 21″ | 533 mm |
| Circumference | 92.19″ | 2342 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.
265/40R21 compared with other sizes
All 24 practical swaps involving 265/40R21 — diameter change, speedometer impact and a fit verdict for each.
265/40R21 → 265/50R19
265/50R19
Diameter −0.3% · This fits
265/40R21 → 295/35R20
295/35R20
Diameter +4.3% · Borderline. Check clearance first
265/40R21 → 235/55R19
235/55R19
Diameter +0.6% · This fits
265/40R21 → 245/55R19
245/55R19
Diameter −0.9% · This fits
265/40R21 → 255/50R19
255/50R19
Diameter +1.1% · This fits
265/40R21 → 245/50R20
245/50R20
Diameter −1.0% · This fits
265/40R21 → 265/45R20
265/45R20
Diameter −0.1% · This fits
285/40R21 → 265/40R21
285/40R21
Diameter +2.1% · This fits
265/45R21 → 265/40R21
265/45R21
Diameter +3.6% · Borderline. Check clearance first
265/45R20 → 265/40R21
265/45R20
Diameter +0.1% · This fits
265/50R19 → 265/40R21
265/50R19
Diameter +0.3% · This fits
275/45R21 → 265/40R21
275/45R21
Diameter +4.8% · Borderline. Check clearance first
235/55R19 → 265/40R21
235/55R19
Diameter −0.6% · This fits
245/55R19 → 265/40R21
245/55R19
Diameter +0.9% · This fits
245/50R20 → 265/40R21
245/50R20
Diameter +1.0% · This fits
255/50R19 → 265/40R21
255/50R19
Diameter −1.0% · This fits
255/45R20 → 265/40R21
255/45R20
Diameter −1.1% · This fits
275/45R20 → 265/40R21
275/45R20
Diameter +1.4% · This fits
245/45R20 → 265/40R21
245/45R20
Diameter −2.3% · This fits
275/40R20 → 265/40R21
275/40R20
Diameter −2.3% · This fits
255/50R20 → 265/40R21
255/50R20
Diameter +2.4% · This fits
265/40R21 → 265/45R21
265/45R21
Diameter −3.4% · Borderline. Check clearance first
265/40R21 → 275/45R21
275/45R21
Diameter −4.5% · Borderline. Check clearance first
265/40R21 → 285/40R21
285/40R21
Diameter −2.1% · This fits
Common questions
- What is 265/40R21 in inches?
- A 265/40R21 tire is 29.35 inches tall and 10.4 inches wide, with a 4.17-inch sidewall, mounted on a 21-inch wheel. In metric that is 745 mm tall and 265 mm wide. The circumference is 92.19 inches.
- How tall is a 265/40R21 tire?
- 29.35 inches, or 745 mm. That is the overall diameter, wheel included. It turns about 687 times per mile, which is what your speedometer counts.
- What do the numbers in 265/40R21 mean?
- 265 is the tread width in millimeters, 40 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 265 × 40% = 106.0 mm tall.