325/45R18 tire size in inches
A 325/45R18 tire measures
29.5" tall × 12.8" wide
5.76" sidewall on a 18" wheel. 683 revolutions per mile.
325/45R18 means a tire 325 mm wide, with sidewalls 45% as tall as the tire is wide (146 mm), radial construction (R), for a 18 inch wheel.
325/45R18 specs
| Overall diameter (height) | 29.52 inches (750 mm) |
|---|---|
| Section width | 12.80 inches (325 mm) |
| Sidewall height | 5.76 inches (146 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 92.7 inches (2,355 mm) |
| Revolutions per mile | 683 |
| Revolutions per kilometer | 425 |
| Approximate rim width | 10.5" to 12.0" |
| In inches (flotation style) | 29.5x12.8R18 |
| 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 325/45R18 on a 18" wheel
These 18" sizes are within 3% of 325/45R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 195/75R18 | 29.52" | 7.68" | 0.0% | 60.0 mph | Compare |
| 225/65R18 | 29.52" | 8.86" | 0.0% | 60.0 mph | Compare |
| 265/55R18 | 29.48" | 10.43" | −0.1% | 59.9 mph | Compare |
| 245/60R18 | 29.57" | 9.65" | +0.2% | 60.1 mph | Compare |
| 295/50R18 | 29.61" | 11.61" | +0.3% | 60.2 mph | Compare |
| 205/70R18 | 29.30" | 8.07" | −0.7% | 59.6 mph | Compare |
| 285/50R18 | 29.22" | 11.22" | −1.0% | 59.4 mph | Compare |
| 215/70R18 | 29.85" | 8.46" | +1.1% | 60.7 mph | Compare |
| 315/45R18 | 29.16" | 12.40" | −1.2% | 59.3 mph | Compare |
| 335/45R18 | 29.87" | 13.19" | +1.2% | 60.7 mph | Compare |
| 275/55R18 | 29.91" | 10.83" | +1.3% | 60.8 mph | Compare |
| 235/60R18 | 29.10" | 9.25" | −1.4% | 59.2 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 265/60R17 | 17" | 29.52" | 0.0% | Compare |
| 345/35R20 | 20" | 29.51" | 0.0% | Compare |
| 245/70R16 | 16" | 29.50" | 0.0% | Compare |
| 205/65R19 | 19" | 29.49" | −0.1% | Compare |
| 245/65R17 | 17" | 29.54" | +0.1% | Compare |
| 215/80R16 | 16" | 29.54" | +0.1% | Compare |
| 335/40R19 | 19" | 29.55" | +0.1% | Compare |
| 245/75R15 | 15" | 29.47" | −0.2% | Compare |
| 265/65R16 | 16" | 29.56" | +0.2% | Compare |
| 285/60R16 | 16" | 29.46" | −0.2% | Compare |
| 275/35R22 | 22" | 29.58" | +0.2% | Compare |
| 295/45R19 | 19" | 29.45" | −0.2% | Compare |
One size up or down
- 315/45R18narrower: 29.2" × 12.4"
- 335/45R18wider: 29.9" × 13.2"
- 325/40R18lower profile: 28.2" × 12.8"
- 325/50R18taller sidewall: 30.8" × 12.8"
Compare 325/45R18 with another size
Questions
- How tall is a 325/45R18 tire?
- A 325/45R18 tire is 29.5 inches tall (750 mm), calculated from the size. It is 12.8 inches wide with 5.8 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 325/45R18 mean?
- 325/45R18 means a tire 325 mm wide, with sidewalls 45% as tall as the tire is wide (146 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 325/45R18 tire make?
- About 683 revolutions per mile, based on a circumference of 92.7 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 325/45R18 tire?
- Roughly 10.5" to 12.0". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 195/75R18 instead of 325/45R18?
- 195/75R18 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.