255/45R20 tire size in inches
A 255/45R20 tire measures
29.0" tall × 10.0" wide
4.52" sidewall on a 20" wheel. 695 revolutions per mile.
255/45R20 means a tire 255 mm wide, with sidewalls 45% as tall as the tire is wide (115 mm), radial construction (R), for a 20 inch wheel.
255/45R20 specs
| Overall diameter (height) | 29.04 inches (737 mm) |
|---|---|
| Section width | 10.04 inches (255 mm) |
| Sidewall height | 4.52 inches (115 mm) |
| Wheel (rim) diameter | 20 inches |
| Circumference | 91.2 inches (2,317 mm) |
| Revolutions per mile | 695 |
| Revolutions per kilometer | 432 |
| Approximate rim width | 8.5" to 10.0" |
| In inches (flotation style) | 29.0x10.0R20 |
| Aspect ratio | 45% |
Calculated from the size. Real tires differ by brand, model and tread depth, typically by a few tenths of an inch.
Sizes that can replace 255/45R20 on a 20" wheel
These 20" sizes are within 3% of 255/45R20's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 285/40R20 | 28.98" | 11.22" | −0.2% | 59.9 mph | Compare |
| 325/35R20 | 28.96" | 12.80" | −0.3% | 59.8 mph | Compare |
| 225/50R20 | 28.86" | 8.86" | −0.6% | 59.6 mph | Compare |
| 335/35R20 | 29.23" | 13.19" | +0.7% | 60.4 mph | Compare |
| 235/50R20 | 29.25" | 9.25" | +0.7% | 60.4 mph | Compare |
| 295/40R20 | 29.29" | 11.61" | +0.9% | 60.5 mph | Compare |
| 215/55R20 | 29.31" | 8.46" | +0.9% | 60.6 mph | Compare |
| 245/45R20 | 28.68" | 9.65" | −1.2% | 59.3 mph | Compare |
| 315/35R20 | 28.68" | 12.40" | −1.2% | 59.3 mph | Compare |
| 265/45R20 | 29.39" | 10.43" | +1.2% | 60.7 mph | Compare |
| 275/40R20 | 28.66" | 10.83" | −1.3% | 59.2 mph | Compare |
| 345/35R20 | 29.51" | 13.58" | +1.6% | 61.0 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 255/50R19 | 19" | 29.04" | 0.0% | Compare |
| 255/40R21 | 21" | 29.03" | 0.0% | Compare |
| 235/65R17 | 17" | 29.03" | 0.0% | Compare |
| 255/35R22 | 22" | 29.03" | 0.0% | Compare |
| 255/55R18 | 18" | 29.04" | 0.0% | Compare |
| 255/60R17 | 17" | 29.05" | 0.0% | Compare |
| 255/25R24 | 24" | 29.02" | −0.1% | Compare |
| 195/85R16 | 16" | 29.05" | +0.1% | Compare |
| 255/65R16 | 16" | 29.05" | +0.1% | Compare |
| 255/70R15 | 15" | 29.06" | +0.1% | Compare |
| 225/85R14 | 14" | 29.06" | +0.1% | Compare |
| 255/75R14 | 14" | 29.06" | +0.1% | Compare |
One size up or down
- 245/45R20narrower: 28.7" × 9.6"
- 265/45R20wider: 29.4" × 10.4"
- 255/40R20lower profile: 28.0" × 10.0"
- 255/50R20taller sidewall: 30.0" × 10.0"
Compare 255/45R20 with another size
Questions
- How tall is a 255/45R20 tire?
- A 255/45R20 tire is 29.0 inches tall (737 mm), calculated from the size. It is 10.0 inches wide with 4.5 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 255/45R20 mean?
- 255/45R20 means a tire 255 mm wide, with sidewalls 45% as tall as the tire is wide (115 mm), radial construction (R), for a 20 inch wheel.
- How many revolutions per mile does a 255/45R20 tire make?
- About 695 revolutions per mile, based on a circumference of 91.2 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 255/45R20 tire?
- Roughly 8.5" to 10.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 285/40R20 instead of 255/45R20?
- 285/40R20 is −0.06 inches (−0.2%) in overall diameter, so at an indicated 60 mph you would be doing 59.9 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.