255/45R20
A 255/45R20 tire is 29.04 inches tall and 10.0 inches wide, with a 4.52-inch sidewall, mounted on a 20-inch wheel.
Common fitments: Model Y Performance, Edge
Overall diameter
29.04″
737 mm
Sidewall height
4.52″
114.8 mm
Tread width
255 mm
10.0″
Circumference
91.22″
7.6 ft
Revs per mile
695
432 per km
Wheel diameter
20″
aspect ratio 45%
Cross-section
- Overall diameter
- 29.04″
- Sidewall (each side)
- 4.52″
- Wheel
- 20″
255/45R20 in inches and millimeters
Every dimension of a 255/45R20, converted both ways. Calculated from the size code, accurate to about 1%.
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter (height) | 29.04″ | 737 mm |
| Tread width | 10.0″ | 255 mm |
| Sidewall height | 4.52″ | 114.8 mm |
| Wheel diameter | 20″ | 508 mm |
| Circumference | 91.22″ | 2317 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.
255/45R20 compared with other sizes
All 30 practical swaps involving 255/45R20 — diameter change, speedometer impact and a fit verdict for each.
255/45R20 → 235/60R18
235/60R18
Diameter −0.2% · This fits
255/45R20 → 255/55R18
255/55R18
Diameter −0.0% · This fits
245/45R20 → 255/45R20
245/45R20
Diameter −1.2% · This fits
265/45R20 → 255/45R20
265/45R20
Diameter +1.2% · This fits
275/40R20 → 255/45R20
275/40R20
Diameter −1.3% · This fits
245/50R20 → 255/45R20
245/50R20
Diameter +2.1% · This fits
255/50R20 → 255/45R20
255/50R20
Diameter +3.5% · Borderline. Check clearance first
275/45R20 → 255/45R20
275/45R20
Diameter +2.4% · This fits
295/35R20 → 255/45R20
295/35R20
Diameter −3.1% · Borderline. Check clearance first
255/50R19 → 255/45R20
255/50R19
Diameter +0.0% · This fits
255/55R18 → 255/45R20
255/55R18
Diameter +0.0% · This fits
245/40R20 → 255/45R20
245/40R20
Diameter −4.5% · Borderline. Check clearance first
265/50R20 → 255/45R20
265/50R20
Diameter +4.8% · Borderline. Check clearance first
275/35R20 → 255/45R20
275/35R20
Diameter −5.0% · Too big a jump
235/60R18 → 255/45R20
235/60R18
Diameter +0.2% · This fits
235/55R19 → 255/45R20
235/55R19
Diameter +0.5% · This fits
255/45R20 → 275/45R20
275/45R20
Diameter −2.4% · This fits
255/45R20 → 295/35R20
295/35R20
Diameter +3.2% · Borderline. Check clearance first
255/45R20 → 235/55R19
235/55R19
Diameter −0.5% · This fits
255/45R20 → 255/50R19
255/50R19
Diameter −0.0% · This fits
255/45R20 → 245/40R20
245/40R20
Diameter +4.8% · Borderline. Check clearance first
255/45R20 → 245/45R20
245/45R20
Diameter +1.2% · This fits
255/45R20 → 245/50R20
245/50R20
Diameter −2.1% · This fits
255/45R20 → 255/50R20
255/50R20
Diameter −3.3% · Borderline. Check clearance first
255/45R20 → 265/45R20
265/45R20
Diameter −1.2% · This fits
255/45R20 → 265/50R20
265/50R20
Diameter −4.6% · Borderline. Check clearance first
255/45R20 → 275/35R20
275/35R20
Diameter +5.3% · Too big a jump
255/45R20 → 275/40R20
275/40R20
Diameter +1.3% · This fits
255/45R20 → 265/40R21
265/40R21
Diameter −1.1% · This fits
255/45R20 → 275/55R20
275/55R20
Diameter −9.0% · Too big a jump
Common questions
- What is 255/45R20 in inches?
- A 255/45R20 tire is 29.04 inches tall and 10.0 inches wide, with a 4.52-inch sidewall, mounted on a 20-inch wheel. In metric that is 737 mm tall and 255 mm wide. The circumference is 91.22 inches.
- How tall is a 255/45R20 tire?
- 29.04 inches, or 737 mm. That is the overall diameter, wheel included. It turns about 695 times per mile, which is what your speedometer counts.
- What do the numbers in 255/45R20 mean?
- 255 is the tread width in millimeters, 45 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 × 45% = 114.8 mm tall.