225/55R18 tire size in inches
A 225/55R18 tire measures
27.7" tall × 8.9" wide
4.87" sidewall on a 18" wheel. 727 revolutions per mile.
225/55R18 means a tire 225 mm wide, with sidewalls 55% as tall as the tire is wide (124 mm), radial construction (R), for a 18 inch wheel.
225/55R18 specs
| Overall diameter (height) | 27.74 inches (705 mm) |
|---|---|
| Section width | 8.86 inches (225 mm) |
| Sidewall height | 4.87 inches (124 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 87.2 inches (2,214 mm) |
| Revolutions per mile | 727 |
| Revolutions per kilometer | 452 |
| Approximate rim width | 6.5" to 8.0" |
| In inches (flotation style) | 27.7x8.9R18 |
| Aspect ratio | 55% |
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 225/55R18 on a 18" wheel
These 18" sizes are within 3% of 225/55R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 275/45R18 | 27.74" | 10.83" | 0.0% | 60.0 mph | Compare |
| 205/60R18 | 27.69" | 8.07" | −0.2% | 59.9 mph | Compare |
| 245/50R18 | 27.65" | 9.65" | −0.4% | 59.8 mph | Compare |
| 305/40R18 | 27.61" | 12.01" | −0.5% | 59.7 mph | Compare |
| 315/40R18 | 27.92" | 12.40" | +0.6% | 60.4 mph | Compare |
| 195/65R18 | 27.98" | 7.68" | +0.9% | 60.5 mph | Compare |
| 255/50R18 | 28.04" | 10.04" | +1.1% | 60.6 mph | Compare |
| 285/45R18 | 28.10" | 11.22" | +1.3% | 60.8 mph | Compare |
| 265/45R18 | 27.39" | 10.43" | −1.3% | 59.2 mph | Compare |
| 215/60R18 | 28.16" | 8.46" | +1.5% | 60.9 mph | Compare |
| 215/55R18 | 27.31" | 8.46" | −1.6% | 59.1 mph | Compare |
| 235/55R18 | 28.18" | 9.25" | +1.6% | 60.9 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 195/70R17 | 17" | 27.75" | 0.0% | Compare |
| 245/35R21 | 21" | 27.75" | 0.0% | Compare |
| 285/30R21 | 21" | 27.73" | 0.0% | Compare |
| 205/85R14 | 14" | 27.72" | −0.1% | Compare |
| 245/40R20 | 20" | 27.72" | −0.1% | Compare |
| 175/85R16 | 16" | 27.71" | −0.1% | Compare |
| 245/30R22 | 22" | 27.79" | +0.2% | Compare |
| 215/75R15 | 15" | 27.70" | −0.2% | Compare |
| 345/25R21 | 21" | 27.79" | +0.2% | Compare |
| 235/80R13 | 13" | 27.80" | +0.2% | Compare |
| 245/45R19 | 19" | 27.68" | −0.2% | Compare |
| 295/25R22 | 22" | 27.81" | +0.2% | Compare |
One size up or down
- 215/55R18narrower: 27.3" × 8.5"
- 235/55R18wider: 28.2" × 9.3"
- 225/50R18lower profile: 26.9" × 8.9"
- 225/60R18taller sidewall: 28.6" × 8.9"
Compare 225/55R18 with another size
Questions
- How tall is a 225/55R18 tire?
- A 225/55R18 tire is 27.7 inches tall (705 mm), calculated from the size. It is 8.9 inches wide with 4.9 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 225/55R18 mean?
- 225/55R18 means a tire 225 mm wide, with sidewalls 55% as tall as the tire is wide (124 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 225/55R18 tire make?
- About 727 revolutions per mile, based on a circumference of 87.2 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 225/55R18 tire?
- Roughly 6.5" to 8.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 275/45R18 instead of 225/55R18?
- 275/45R18 is 0.00 inches (0.0%) in overall diameter, so at an indicated 60 mph you would be doing 60.0 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.