235/45R18 tire size in inches
A 235/45R18 tire measures
26.3" tall × 9.3" wide
4.16" sidewall on a 18" wheel. 766 revolutions per mile.
235/45R18 means a tire 235 mm wide, with sidewalls 45% as tall as the tire is wide (106 mm), radial construction (R), for a 18 inch wheel.
235/45R18 specs
| Overall diameter (height) | 26.33 inches (669 mm) |
|---|---|
| Section width | 9.25 inches (235 mm) |
| Sidewall height | 4.16 inches (106 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 82.7 inches (2,101 mm) |
| Revolutions per mile | 766 |
| Revolutions per kilometer | 476 |
| Approximate rim width | 7.5" to 9.0" |
| In inches (flotation style) | 26.3x9.3R18 |
| 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 235/45R18 on a 18" wheel
These 18" sizes are within 3% of 235/45R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 265/40R18 | 26.35" | 10.43" | +0.1% | 60.0 mph | Compare |
| 305/35R18 | 26.41" | 12.01" | +0.3% | 60.2 mph | Compare |
| 195/55R18 | 26.44" | 7.68" | +0.4% | 60.3 mph | Compare |
| 215/50R18 | 26.46" | 8.46" | +0.5% | 60.3 mph | Compare |
| 295/35R18 | 26.13" | 11.61" | −0.7% | 59.6 mph | Compare |
| 205/50R18 | 26.07" | 8.07" | −1.0% | 59.4 mph | Compare |
| 255/40R18 | 26.03" | 10.04" | −1.1% | 59.3 mph | Compare |
| 275/40R18 | 26.66" | 10.83" | +1.3% | 60.8 mph | Compare |
| 225/45R18 | 25.97" | 8.86" | −1.3% | 59.2 mph | Compare |
| 245/45R18 | 26.68" | 9.65" | +1.3% | 60.8 mph | Compare |
| 315/35R18 | 26.68" | 12.40" | +1.3% | 60.8 mph | Compare |
| 285/35R18 | 25.85" | 11.22" | −1.8% | 58.9 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 175/75R16 | 16" | 26.33" | 0.0% | Compare |
| 225/30R21 | 21" | 26.31" | 0.0% | Compare |
| 215/55R17 | 17" | 26.31" | −0.1% | Compare |
| 265/35R19 | 19" | 26.30" | −0.1% | Compare |
| 205/70R15 | 15" | 26.30" | −0.1% | Compare |
| 295/40R17 | 17" | 26.29" | −0.1% | Compare |
| 225/75R13 | 13" | 26.29" | −0.1% | Compare |
| 195/80R14 | 14" | 26.28" | −0.2% | Compare |
| 185/85R14 | 14" | 26.38" | +0.2% | Compare |
| 205/45R19 | 19" | 26.26" | −0.2% | Compare |
| 265/45R17 | 17" | 26.39" | +0.2% | Compare |
| 265/30R20 | 20" | 26.26" | −0.3% | Compare |
One size up or down
- 225/45R18narrower: 26.0" × 8.9"
- 245/45R18wider: 26.7" × 9.6"
- 235/40R18lower profile: 25.4" × 9.3"
- 235/50R18taller sidewall: 27.3" × 9.3"
Compare 235/45R18 with another size
Questions
- How tall is a 235/45R18 tire?
- A 235/45R18 tire is 26.3 inches tall (669 mm), calculated from the size. It is 9.3 inches wide with 4.2 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 235/45R18 mean?
- 235/45R18 means a tire 235 mm wide, with sidewalls 45% as tall as the tire is wide (106 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 235/45R18 tire make?
- About 766 revolutions per mile, based on a circumference of 82.7 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 235/45R18 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 265/40R18 instead of 235/45R18?
- 265/40R18 is +0.02 inches (+0.1%) 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.