205/45R18 tire size in inches
A 205/45R18 tire measures
25.3" tall × 8.1" wide
3.63" sidewall on a 18" wheel. 798 revolutions per mile.
205/45R18 means a tire 205 mm wide, with sidewalls 45% as tall as the tire is wide (92 mm), radial construction (R), for a 18 inch wheel.
205/45R18 specs
| Overall diameter (height) | 25.26 inches (642 mm) |
|---|---|
| Section width | 8.07 inches (205 mm) |
| Sidewall height | 3.63 inches (92 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 79.4 inches (2,016 mm) |
| Revolutions per mile | 798 |
| Revolutions per kilometer | 496 |
| Approximate rim width | 6.5" to 8.0" |
| In inches (flotation style) | 25.3x8.1R18 |
| 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 205/45R18 on a 18" wheel
These 18" sizes are within 3% of 205/45R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 265/35R18 | 25.30" | 10.43" | +0.2% | 60.1 mph | Compare |
| 235/40R18 | 25.40" | 9.25" | +0.5% | 60.3 mph | Compare |
| 225/40R18 | 25.09" | 8.86" | −0.7% | 59.6 mph | Compare |
| 255/35R18 | 25.03" | 10.04" | −0.9% | 59.4 mph | Compare |
| 275/35R18 | 25.58" | 10.83" | +1.2% | 60.7 mph | Compare |
| 195/45R18 | 24.91" | 7.68" | −1.4% | 59.2 mph | Compare |
| 215/45R18 | 25.62" | 8.46" | +1.4% | 60.8 mph | Compare |
| 195/50R18 | 25.68" | 7.68" | +1.6% | 61.0 mph | Compare |
| 245/40R18 | 25.72" | 9.65" | +1.8% | 61.1 mph | Compare |
| 215/40R18 | 24.77" | 8.46" | −1.9% | 58.8 mph | Compare |
| 245/35R18 | 24.75" | 9.65" | −2.0% | 58.8 mph | Compare |
| 285/35R18 | 25.85" | 11.22" | +2.3% | 61.4 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 265/30R19 | 19" | 25.26" | 0.0% | Compare |
| 235/50R16 | 16" | 25.25" | 0.0% | Compare |
| 195/80R13 | 13" | 25.28" | +0.1% | Compare |
| 295/40R16 | 16" | 25.29" | +0.1% | Compare |
| 205/70R14 | 14" | 25.30" | +0.1% | Compare |
| 215/55R16 | 16" | 25.31" | +0.2% | Compare |
| 265/25R20 | 20" | 25.22" | −0.2% | Compare |
| 195/60R16 | 16" | 25.21" | −0.2% | Compare |
| 225/30R20 | 20" | 25.31" | +0.2% | Compare |
| 225/35R19 | 19" | 25.20" | −0.2% | Compare |
| 235/45R17 | 17" | 25.33" | +0.2% | Compare |
| 315/25R19 | 19" | 25.20" | −0.2% | Compare |
One size up or down
- 195/45R18narrower: 24.9" × 7.7"
- 215/45R18wider: 25.6" × 8.5"
- 205/40R18lower profile: 24.5" × 8.1"
- 205/50R18taller sidewall: 26.1" × 8.1"
Compare 205/45R18 with another size
Questions
- How tall is a 205/45R18 tire?
- A 205/45R18 tire is 25.3 inches tall (642 mm), calculated from the size. It is 8.1 inches wide with 3.6 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 205/45R18 mean?
- 205/45R18 means a tire 205 mm wide, with sidewalls 45% as tall as the tire is wide (92 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 205/45R18 tire make?
- About 798 revolutions per mile, based on a circumference of 79.4 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 205/45R18 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 265/35R18 instead of 205/45R18?
- 265/35R18 is +0.04 inches (+0.2%) in overall diameter, so at an indicated 60 mph you would be doing 60.1 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.