245/40R20
A 245/40R20 tire is 27.72 inches tall and 9.6 inches wide, with a 3.86-inch sidewall, mounted on a 20-inch wheel.
Overall diameter
27.72″
704 mm
Sidewall height
3.86″
98.0 mm
Tread width
245 mm
9.6″
Circumference
87.07″
7.3 ft
Revs per mile
728
452 per km
Wheel diameter
20″
aspect ratio 40%
Cross-section
- Overall diameter
- 27.72″
- Sidewall (each side)
- 3.86″
- Wheel
- 20″
245/40R20 in inches and millimeters
Every dimension of a 245/40R20, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 27.72″ | 704 mm |
| Tread width | 9.6″ | 245 mm |
| Sidewall height | 3.86″ | 98.0 mm |
| Wheel diameter | 20″ | 508 mm |
| Circumference | 87.07″ | 2212 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.
245/40R20 compared with other sizes
All 25 practical swaps involving 245/40R20 — diameter change, speedometer impact and a fit verdict for each.
245/40R20 → 245/45R19
245/45R19
Diameter +0.1% · This fits
245/40R20 → 275/40R19
275/40R19
Diameter +0.2% · This fits
245/40R20 → 245/35R20
245/35R20
Diameter +3.6% · Borderline. Check clearance first
245/40R20 → 255/35R20
255/35R20
Diameter +2.5% · This fits
245/40R20 → 255/45R20
255/45R20
Diameter −4.5% · Borderline. Check clearance first
245/40R20 → 255/45R19
255/45R19
Diameter −1.1% · This fits
275/35R20 → 245/40R20
275/35R20
Diameter −0.5% · This fits
265/35R20 → 245/40R20
265/35R20
Diameter −1.5% · This fits
245/35R20 → 245/40R20
245/35R20
Diameter −3.5% · Borderline. Check clearance first
245/45R20 → 245/40R20
245/45R20
Diameter +3.5% · Borderline. Check clearance first
255/35R20 → 245/40R20
255/35R20
Diameter −2.5% · This fits
275/40R20 → 245/40R20
275/40R20
Diameter +3.4% · Borderline. Check clearance first
245/45R19 → 245/40R20
245/45R19
Diameter −0.1% · This fits
255/45R20 → 245/40R20
255/45R20
Diameter +4.8% · Borderline. Check clearance first
275/40R19 → 245/40R20
275/40R19
Diameter −0.2% · This fits
255/45R19 → 245/40R20
255/45R19
Diameter +1.2% · This fits
235/45R19 → 245/40R20
235/45R19
Diameter −1.4% · This fits
235/55R18 → 245/40R20
235/55R18
Diameter +1.7% · This fits
235/50R18 → 245/40R20
235/50R18
Diameter −1.7% · This fits
235/50R19 → 245/40R20
235/50R19
Diameter +1.9% · This fits
245/40R20 → 245/45R20
245/45R20
Diameter −3.4% · Borderline. Check clearance first
245/40R20 → 265/35R20
265/35R20
Diameter +1.5% · This fits
245/40R20 → 275/35R20
275/35R20
Diameter +0.5% · This fits
245/40R20 → 275/40R20
275/40R20
Diameter −3.3% · Borderline. Check clearance first
245/40R20 → 275/55R20
275/55R20
Diameter −13.1% · Too big a jump
Common questions
- What is 245/40R20 in inches?
- A 245/40R20 tire is 27.72 inches tall and 9.6 inches wide, with a 3.86-inch sidewall, mounted on a 20-inch wheel. In metric that is 704 mm tall and 245 mm wide. The circumference is 87.07 inches.
- How tall is a 245/40R20 tire?
- 27.72 inches, or 704 mm. That is the overall diameter, wheel included. It turns about 728 times per mile, which is what your speedometer counts.
- What do the numbers in 245/40R20 mean?
- 245 is the tread width in millimeters, 40 is the aspect ratio — the sidewall height as a percentage of the tread width — and 20 is the wheel diameter in inches. So the sidewall is 245 × 40% = 98.0 mm tall.