245/40R20 tire size in inches
A 245/40R20 tire measures
27.7" tall × 9.6" wide
3.86" sidewall on a 20" wheel. 728 revolutions per mile.
245/40R20 means a tire 245 mm wide, with sidewalls 40% as tall as the tire is wide (98 mm), radial construction (R), for a 20 inch wheel.
245/40R20 specs
| Overall diameter (height) | 27.72 inches (704 mm) |
|---|---|
| Section width | 9.65 inches (245 mm) |
| Sidewall height | 3.86 inches (98 mm) |
| Wheel (rim) diameter | 20 inches |
| Circumference | 87.1 inches (2,212 mm) |
| Revolutions per mile | 728 |
| Revolutions per kilometer | 452 |
| Approximate rim width | 8.0" to 9.5" |
| In inches (flotation style) | 27.7x9.6R20 |
| 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 245/40R20 on a 20" wheel
These 20" sizes are within 3% of 245/40R20's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 325/30R20 | 27.68" | 12.80" | −0.1% | 59.9 mph | Compare |
| 215/45R20 | 27.62" | 8.46" | −0.4% | 59.8 mph | Compare |
| 275/35R20 | 27.58" | 10.83" | −0.5% | 59.7 mph | Compare |
| 285/35R20 | 27.85" | 11.22" | +0.5% | 60.3 mph | Compare |
| 335/30R20 | 27.91" | 13.19" | +0.7% | 60.4 mph | Compare |
| 225/45R20 | 27.97" | 8.86" | +0.9% | 60.6 mph | Compare |
| 315/30R20 | 27.44" | 12.40" | −1.0% | 59.4 mph | Compare |
| 235/40R20 | 27.40" | 9.25" | −1.1% | 59.3 mph | Compare |
| 255/40R20 | 28.03" | 10.04" | +1.1% | 60.7 mph | Compare |
| 265/35R20 | 27.30" | 10.43" | −1.5% | 59.1 mph | Compare |
| 295/35R20 | 28.13" | 11.61" | +1.5% | 60.9 mph | Compare |
| 345/30R20 | 28.15" | 13.58" | +1.6% | 60.9 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 175/85R16 | 16" | 27.71" | 0.0% | Compare |
| 205/85R14 | 14" | 27.72" | 0.0% | Compare |
| 285/30R21 | 21" | 27.73" | +0.1% | Compare |
| 215/75R15 | 15" | 27.70" | −0.1% | Compare |
| 225/55R18 | 18" | 27.74" | +0.1% | Compare |
| 275/45R18 | 18" | 27.74" | +0.1% | Compare |
| 195/70R17 | 17" | 27.75" | +0.1% | Compare |
| 205/60R18 | 18" | 27.69" | −0.1% | Compare |
| 245/45R19 | 19" | 27.68" | −0.1% | Compare |
| 245/35R21 | 21" | 27.75" | +0.1% | Compare |
| 315/35R19 | 19" | 27.68" | −0.1% | Compare |
| 275/40R19 | 19" | 27.66" | −0.2% | Compare |
One size up or down
- 235/40R20narrower: 27.4" × 9.3"
- 255/40R20wider: 28.0" × 10.0"
- 245/35R20lower profile: 26.8" × 9.6"
- 245/45R20taller sidewall: 28.7" × 9.6"
Compare 245/40R20 with another size
Questions
- How tall is a 245/40R20 tire?
- A 245/40R20 tire is 27.7 inches tall (704 mm), calculated from the size. It is 9.6 inches wide with 3.9 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 245/40R20 mean?
- 245/40R20 means a tire 245 mm wide, with sidewalls 40% as tall as the tire is wide (98 mm), radial construction (R), for a 20 inch wheel.
- How many revolutions per mile does a 245/40R20 tire make?
- About 728 revolutions per mile, based on a circumference of 87.1 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 245/40R20 tire?
- Roughly 8.0" to 9.5". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 325/30R20 instead of 245/40R20?
- 325/30R20 is −0.04 inches (−0.1%) 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.