195/45R18 tire size in inches
A 195/45R18 tire measures
24.9" tall × 7.7" wide
3.45" sidewall on a 18" wheel. 810 revolutions per mile.
195/45R18 means a tire 195 mm wide, with sidewalls 45% as tall as the tire is wide (88 mm), radial construction (R), for a 18 inch wheel.
195/45R18 specs
| Overall diameter (height) | 24.91 inches (633 mm) |
|---|---|
| Section width | 7.68 inches (195 mm) |
| Sidewall height | 3.45 inches (88 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 78.3 inches (1,988 mm) |
| Revolutions per mile | 810 |
| Revolutions per kilometer | 503 |
| Approximate rim width | 6.5" to 8.0" |
| In inches (flotation style) | 24.9x7.7R18 |
| 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 195/45R18 on a 18" wheel
These 18" sizes are within 3% of 195/45R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 255/35R18 | 25.03" | 10.04" | +0.5% | 60.3 mph | Compare |
| 215/40R18 | 24.77" | 8.46" | −0.6% | 59.7 mph | Compare |
| 245/35R18 | 24.75" | 9.65" | −0.6% | 59.6 mph | Compare |
| 225/40R18 | 25.09" | 8.86" | +0.7% | 60.4 mph | Compare |
| 205/45R18 | 25.26" | 8.07" | +1.4% | 60.9 mph | Compare |
| 265/35R18 | 25.30" | 10.43" | +1.6% | 60.9 mph | Compare |
| 235/35R18 | 24.48" | 9.25" | −1.7% | 59.0 mph | Compare |
| 205/40R18 | 24.46" | 8.07" | −1.8% | 58.9 mph | Compare |
| 235/40R18 | 25.40" | 9.25" | +2.0% | 61.2 mph | Compare |
| 275/35R18 | 25.58" | 10.83" | +2.7% | 61.6 mph | Compare |
| 225/35R18 | 24.20" | 8.86" | −2.8% | 58.3 mph | Compare |
| 215/45R18 | 25.62" | 8.46" | +2.8% | 61.7 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 215/35R19 | 19" | 24.93" | +0.1% | Compare |
| 185/75R14 | 14" | 24.93" | +0.1% | Compare |
| 205/55R16 | 16" | 24.88" | −0.1% | Compare |
| 175/65R16 | 16" | 24.96" | +0.2% | Compare |
| 225/50R16 | 16" | 24.86" | −0.2% | Compare |
| 285/35R17 | 17" | 24.85" | −0.2% | Compare |
| 215/70R13 | 13" | 24.85" | −0.2% | Compare |
| 225/45R17 | 17" | 24.97" | +0.3% | Compare |
| 285/40R16 | 16" | 24.98" | +0.3% | Compare |
| 195/65R15 | 15" | 24.98" | +0.3% | Compare |
| 245/25R20 | 20" | 24.82" | −0.3% | Compare |
| 215/65R14 | 14" | 25.00" | +0.4% | Compare |
One size up or down
- 205/45R18wider: 25.3" × 8.1"
- 195/40R18lower profile: 24.1" × 7.7"
- 195/50R18taller sidewall: 25.7" × 7.7"
Compare 195/45R18 with another size
Questions
- How tall is a 195/45R18 tire?
- A 195/45R18 tire is 24.9 inches tall (633 mm), calculated from the size. It is 7.7 inches wide with 3.5 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 195/45R18 mean?
- 195/45R18 means a tire 195 mm wide, with sidewalls 45% as tall as the tire is wide (88 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 195/45R18 tire make?
- About 810 revolutions per mile, based on a circumference of 78.3 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 195/45R18 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 255/35R18 instead of 195/45R18?
- 255/35R18 is +0.12 inches (+0.5%) in overall diameter, so at an indicated 60 mph you would be doing 60.3 mph. Differences under 3% are usually fine, but check clearance, load index and your vehicle's placard.