255/40R20 tire size in inches
A 255/40R20 tire measures
28.0" tall × 10.0" wide
4.02" sidewall on a 20" wheel. 719 revolutions per mile.
255/40R20 means a tire 255 mm wide, with sidewalls 40% as tall as the tire is wide (102 mm), radial construction (R), for a 20 inch wheel.
255/40R20 specs
| Overall diameter (height) | 28.03 inches (712 mm) |
|---|---|
| Section width | 10.04 inches (255 mm) |
| Sidewall height | 4.02 inches (102 mm) |
| Wheel (rim) diameter | 20 inches |
| Circumference | 88.1 inches (2,237 mm) |
| Revolutions per mile | 719 |
| Revolutions per kilometer | 447 |
| Approximate rim width | 8.5" to 10.0" |
| In inches (flotation style) | 28.0x10.0R20 |
| Aspect ratio | 40% |
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 255/40R20 on a 20" wheel
These 20" sizes are within 3% of 255/40R20's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 225/45R20 | 27.97" | 8.86" | −0.2% | 59.9 mph | Compare |
| 295/35R20 | 28.13" | 11.61" | +0.4% | 60.2 mph | Compare |
| 335/30R20 | 27.91" | 13.19" | −0.4% | 59.7 mph | Compare |
| 345/30R20 | 28.15" | 13.58" | +0.4% | 60.3 mph | Compare |
| 285/35R20 | 27.85" | 11.22" | −0.6% | 59.6 mph | Compare |
| 235/45R20 | 28.33" | 9.25" | +1.1% | 60.6 mph | Compare |
| 245/40R20 | 27.72" | 9.65" | −1.1% | 59.3 mph | Compare |
| 265/40R20 | 28.35" | 10.43" | +1.1% | 60.7 mph | Compare |
| 325/30R20 | 27.68" | 12.80" | −1.3% | 59.2 mph | Compare |
| 355/30R20 | 28.39" | 13.98" | +1.3% | 60.8 mph | Compare |
| 305/35R20 | 28.41" | 12.01" | +1.3% | 60.8 mph | Compare |
| 215/45R20 | 27.62" | 8.46" | −1.5% | 59.1 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 235/65R16 | 16" | 28.03" | 0.0% | Compare |
| 255/45R19 | 19" | 28.04" | 0.0% | Compare |
| 255/35R21 | 21" | 28.03" | 0.0% | Compare |
| 255/50R18 | 18" | 28.04" | 0.0% | Compare |
| 255/30R22 | 22" | 28.02" | 0.0% | Compare |
| 255/55R17 | 17" | 28.04" | 0.0% | Compare |
| 255/60R16 | 16" | 28.05" | +0.1% | Compare |
| 195/85R15 | 15" | 28.05" | +0.1% | Compare |
| 255/65R15 | 15" | 28.05" | +0.1% | Compare |
| 255/70R14 | 14" | 28.06" | +0.1% | Compare |
| 215/65R17 | 17" | 28.00" | −0.1% | Compare |
| 225/85R13 | 13" | 28.06" | +0.1% | Compare |
One size up or down
- 245/40R20narrower: 27.7" × 9.6"
- 265/40R20wider: 28.3" × 10.4"
- 255/35R20lower profile: 27.0" × 10.0"
- 255/45R20taller sidewall: 29.0" × 10.0"
Compare 255/40R20 with another size
Questions
- How tall is a 255/40R20 tire?
- A 255/40R20 tire is 28.0 inches tall (712 mm), calculated from the size. It is 10.0 inches wide with 4.0 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 255/40R20 mean?
- 255/40R20 means a tire 255 mm wide, with sidewalls 40% as tall as the tire is wide (102 mm), radial construction (R), for a 20 inch wheel.
- How many revolutions per mile does a 255/40R20 tire make?
- About 719 revolutions per mile, based on a circumference of 88.1 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 255/40R20 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 225/45R20 instead of 255/40R20?
- 225/45R20 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.