195/40R18 tire size in inches
A 195/40R18 tire measures
24.1" tall × 7.7" wide
3.07" sidewall on a 18" wheel. 835 revolutions per mile.
195/40R18 means a tire 195 mm wide, with sidewalls 40% as tall as the tire is wide (78 mm), radial construction (R), for a 18 inch wheel.
195/40R18 specs
| Overall diameter (height) | 24.14 inches (613 mm) |
|---|---|
| Section width | 7.68 inches (195 mm) |
| Sidewall height | 3.07 inches (78 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 75.8 inches (1,926 mm) |
| Revolutions per mile | 835 |
| Revolutions per kilometer | 519 |
| Approximate rim width | 6.5" to 8.0" |
| In inches (flotation style) | 24.1x7.7R18 |
| Aspect ratio | 40% |
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 195/40R18 on a 18" wheel
These 18" sizes are within 3% of 195/40R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 225/35R18 | 24.20" | 8.86" | +0.2% | 60.1 mph | Compare |
| 215/35R18 | 23.93" | 8.46" | −0.9% | 59.5 mph | Compare |
| 205/40R18 | 24.46" | 8.07" | +1.3% | 60.8 mph | Compare |
| 235/35R18 | 24.48" | 9.25" | +1.4% | 60.8 mph | Compare |
| 205/35R18 | 23.65" | 8.07" | −2.0% | 58.8 mph | Compare |
| 245/35R18 | 24.75" | 9.65" | +2.5% | 61.5 mph | Compare |
| 215/40R18 | 24.77" | 8.46" | +2.6% | 61.6 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 215/60R14 | 14" | 24.16" | +0.1% | Compare |
| 235/55R14 | 14" | 24.18" | +0.1% | Compare |
| 235/60R13 | 13" | 24.10" | −0.2% | Compare |
| 165/70R15 | 15" | 24.09" | −0.2% | Compare |
| 225/40R17 | 17" | 24.09" | −0.2% | Compare |
| 185/70R14 | 14" | 24.20" | +0.2% | Compare |
| 215/30R19 | 19" | 24.08" | −0.3% | Compare |
| 195/60R15 | 15" | 24.21" | +0.3% | Compare |
| 205/50R16 | 16" | 24.07" | −0.3% | Compare |
| 265/25R19 | 19" | 24.22" | +0.3% | Compare |
| 215/25R20 | 20" | 24.23" | +0.4% | Compare |
| 165/85R13 | 13" | 24.04" | −0.4% | Compare |
One size up or down
- 205/40R18wider: 24.5" × 8.1"
- 195/35R18lower profile: 23.4" × 7.7"
- 195/45R18taller sidewall: 24.9" × 7.7"
Compare 195/40R18 with another size
Questions
- How tall is a 195/40R18 tire?
- A 195/40R18 tire is 24.1 inches tall (613 mm), calculated from the size. It is 7.7 inches wide with 3.1 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 195/40R18 mean?
- 195/40R18 means a tire 195 mm wide, with sidewalls 40% as tall as the tire is wide (78 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 195/40R18 tire make?
- About 835 revolutions per mile, based on a circumference of 75.8 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 195/40R18 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 225/35R18 instead of 195/40R18?
- 225/35R18 is +0.06 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.