255/55R20
A 255/55R20 tire is 31.04 inches tall and 10.0 inches wide, with a 5.52-inch sidewall, mounted on a 20-inch wheel.
Overall diameter
31.04″
789 mm
Sidewall height
5.52″
140.3 mm
Tread width
255 mm
10.0″
Circumference
97.53″
8.1 ft
Revs per mile
650
404 per km
Wheel diameter
20″
aspect ratio 55%
Cross-section
- Overall diameter
- 31.04″
- Sidewall (each side)
- 5.52″
- Wheel
- 20″
255/55R20 in inches and millimeters
Every dimension of a 255/55R20, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 31.04″ | 789 mm |
| Tread width | 10.0″ | 255 mm |
| Sidewall height | 5.52″ | 140.3 mm |
| Wheel diameter | 20″ | 508 mm |
| Circumference | 97.53″ | 2477 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.
255/55R20 compared with other sizes
All 30 practical swaps involving 255/55R20 — diameter change, speedometer impact and a fit verdict for each.
255/55R20 → 275/45R20
275/45R20
Diameter +4.4% · Borderline. Check clearance first
255/55R20 → 275/55R20
275/55R20
Diameter −2.7% · This fits
255/55R20 → 255/65R18
255/65R18
Diameter −0.0% · This fits
255/55R20 → 255/60R19
255/60R19
Diameter −0.0% · This fits
255/55R20 → 275/55R19
275/55R19
Diameter +0.4% · This fits
255/55R20 → 245/50R20
245/50R20
Diameter +4.7% · Borderline. Check clearance first
255/55R20 → 255/50R20
255/50R20
Diameter +3.3% · Borderline. Check clearance first
285/50R20 → 255/55R20
285/50R20
Diameter +0.6% · This fits
265/55R20 → 255/55R20
265/55R20
Diameter +1.4% · This fits
265/50R20 → 255/55R20
265/50R20
Diameter −2.0% · This fits
255/50R20 → 255/55R20
255/50R20
Diameter −3.2% · Borderline. Check clearance first
275/55R20 → 255/55R20
275/55R20
Diameter +2.8% · This fits
255/60R19 → 255/55R20
255/60R19
Diameter +0.0% · This fits
255/65R18 → 255/55R20
255/65R18
Diameter +0.0% · This fits
275/45R20 → 255/55R20
275/45R20
Diameter −4.2% · Borderline. Check clearance first
285/55R20 → 255/55R20
285/55R20
Diameter +4.2% · Borderline. Check clearance first
245/50R20 → 255/55R20
245/50R20
Diameter −4.5% · Borderline. Check clearance first
265/60R20 → 255/55R20
265/60R20
Diameter +4.8% · Borderline. Check clearance first
275/60R18 → 255/55R20
275/60R18
Diameter −0.2% · This fits
285/45R21 → 255/55R20
285/45R21
Diameter +0.2% · This fits
285/40R22 → 255/55R20
285/40R22
Diameter −0.2% · This fits
255/55R20 → 265/50R20
265/50R20
Diameter +2.0% · This fits
255/55R20 → 265/55R20
265/55R20
Diameter −1.4% · This fits
255/55R20 → 265/60R20
265/60R20
Diameter −4.5% · Borderline. Check clearance first
255/55R20 → 285/50R20
285/50R20
Diameter −0.6% · This fits
255/55R20 → 285/55R20
285/55R20
Diameter −4.0% · Borderline. Check clearance first
255/55R20 → 275/45R21
275/45R21
Diameter +1.0% · This fits
255/55R20 → 285/45R21
285/45R21
Diameter −0.2% · This fits
255/55R20 → 275/40R22
275/40R22
Diameter +1.2% · This fits
255/55R20 → 285/40R22
285/40R22
Diameter +0.2% · This fits
Common questions
- What is 255/55R20 in inches?
- A 255/55R20 tire is 31.04 inches tall and 10.0 inches wide, with a 5.52-inch sidewall, mounted on a 20-inch wheel. In metric that is 789 mm tall and 255 mm wide. The circumference is 97.53 inches.
- How tall is a 255/55R20 tire?
- 31.04 inches, or 789 mm. That is the overall diameter, wheel included. It turns about 650 times per mile, which is what your speedometer counts.
- What do the numbers in 255/55R20 mean?
- 255 is the tread width in millimeters, 55 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 255 × 55% = 140.3 mm tall.