255/55R18 tire size in inches
A 255/55R18 tire measures
29.0" tall × 10.0" wide
5.52" sidewall on a 18" wheel. 694 revolutions per mile.
255/55R18 means a tire 255 mm wide, with sidewalls 55% as tall as the tire is wide (140 mm), radial construction (R), for a 18 inch wheel.
255/55R18 specs
| Overall diameter (height) | 29.04 inches (738 mm) |
|---|---|
| Section width | 10.04 inches (255 mm) |
| Sidewall height | 5.52 inches (140 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 91.2 inches (2,318 mm) |
| Revolutions per mile | 694 |
| Revolutions per kilometer | 431 |
| Approximate rim width | 7.5" to 9.0" |
| In inches (flotation style) | 29.0x10.0R18 |
| 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 255/55R18 on a 18" wheel
These 18" sizes are within 3% of 255/55R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 215/65R18 | 29.00" | 8.46" | −0.1% | 59.9 mph | Compare |
| 235/60R18 | 29.10" | 9.25" | +0.2% | 60.1 mph | Compare |
| 315/45R18 | 29.16" | 12.40" | +0.4% | 60.2 mph | Compare |
| 285/50R18 | 29.22" | 11.22" | +0.6% | 60.4 mph | Compare |
| 275/50R18 | 28.83" | 10.83" | −0.7% | 59.6 mph | Compare |
| 305/45R18 | 28.81" | 12.01" | −0.8% | 59.5 mph | Compare |
| 205/70R18 | 29.30" | 8.07" | +0.9% | 60.5 mph | Compare |
| 195/70R18 | 28.75" | 7.68" | −1.0% | 59.4 mph | Compare |
| 225/60R18 | 28.63" | 8.86" | −1.4% | 59.1 mph | Compare |
| 265/55R18 | 29.48" | 10.43" | +1.5% | 60.9 mph | Compare |
| 245/55R18 | 28.61" | 9.65" | −1.5% | 59.1 mph | Compare |
| 195/75R18 | 29.52" | 7.68" | +1.6% | 61.0 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 255/60R17 | 17" | 29.05" | 0.0% | Compare |
| 255/50R19 | 19" | 29.04" | 0.0% | Compare |
| 195/85R16 | 16" | 29.05" | 0.0% | Compare |
| 255/65R16 | 16" | 29.05" | 0.0% | Compare |
| 255/45R20 | 20" | 29.04" | 0.0% | Compare |
| 255/70R15 | 15" | 29.06" | 0.0% | Compare |
| 255/40R21 | 21" | 29.03" | 0.0% | Compare |
| 225/85R14 | 14" | 29.06" | +0.1% | Compare |
| 235/65R17 | 17" | 29.03" | −0.1% | Compare |
| 255/75R14 | 14" | 29.06" | +0.1% | Compare |
| 255/35R22 | 22" | 29.03" | −0.1% | Compare |
| 255/25R24 | 24" | 29.02" | −0.1% | Compare |
One size up or down
- 245/55R18narrower: 28.6" × 9.6"
- 265/55R18wider: 29.5" × 10.4"
- 255/50R18lower profile: 28.0" × 10.0"
- 255/60R18taller sidewall: 30.0" × 10.0"
Compare 255/55R18 with another size
Questions
- How tall is a 255/55R18 tire?
- A 255/55R18 tire is 29.0 inches tall (738 mm), calculated from the size. It is 10.0 inches wide with 5.5 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 255/55R18 mean?
- 255/55R18 means a tire 255 mm wide, with sidewalls 55% as tall as the tire is wide (140 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 255/55R18 tire make?
- About 694 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 255/55R18 tire?
- Roughly 7.5" to 9.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 215/65R18 instead of 255/55R18?
- 215/65R18 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.