305/70R18 tire size in inches
A 305/70R18 tire measures
34.8" tall × 12.0" wide
8.41" sidewall on a 18" wheel. 579 revolutions per mile.
305/70R18 means a tire 305 mm wide, with sidewalls 70% as tall as the tire is wide (214 mm), radial construction (R), for a 18 inch wheel.
305/70R18 specs
| Overall diameter (height) | 34.81 inches (884 mm) |
|---|---|
| Section width | 12.01 inches (305 mm) |
| Sidewall height | 8.41 inches (214 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 109.4 inches (2,778 mm) |
| Revolutions per mile | 579 |
| Revolutions per kilometer | 360 |
| Approximate rim width | 8.0" to 9.5" |
| In inches (flotation style) | 34.8x12.0R18 |
| Aspect ratio | 70% |
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 305/70R18 on a 18" wheel
These 18" sizes are within 3% of 305/70R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 285/75R18 | 34.83" | 11.22" | +0.1% | 60.0 mph | Compare |
| 325/65R18 | 34.63" | 12.80" | −0.5% | 59.7 mph | Compare |
| 35x12.50R18 | 35.00" | 12.50" | +0.5% | 60.3 mph | Compare |
| 335/65R18 | 35.15" | 13.19" | +1.0% | 60.6 mph | Compare |
| 295/70R18 | 34.26" | 11.61" | −1.6% | 59.0 mph | Compare |
| 315/70R18 | 35.36" | 12.40" | +1.6% | 61.0 mph | Compare |
| 275/75R18 | 34.24" | 10.83" | −1.6% | 59.0 mph | Compare |
| 295/75R18 | 35.42" | 11.61" | +1.8% | 61.1 mph | Compare |
| 315/65R18 | 34.12" | 12.40" | −2.0% | 58.8 mph | Compare |
| 335/60R18 | 33.83" | 13.19" | −2.8% | 58.3 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 325/50R22 | 22" | 34.80" | 0.0% | Compare |
| 335/60R19 | 19" | 34.83" | 0.0% | Compare |
| 295/55R22 | 22" | 34.78" | −0.1% | Compare |
| 345/40R24 | 24" | 34.87" | +0.2% | Compare |
| 315/60R20 | 20" | 34.88" | +0.2% | Compare |
| 345/55R20 | 20" | 34.94" | +0.4% | Compare |
| 355/50R21 | 21" | 34.98" | +0.5% | Compare |
| 315/55R21 | 21" | 34.64" | −0.5% | Compare |
| 35x12.50R15 | 15" | 35.00" | +0.5% | Compare |
| 35x12.50R17 | 17" | 35.00" | +0.5% | Compare |
| 35x12.50R20 | 20" | 35.00" | +0.5% | Compare |
| 35x12.50R22 | 22" | 35.00" | +0.5% | Compare |
One size up or down
Compare 305/70R18 with another size
Questions
- How tall is a 305/70R18 tire?
- A 305/70R18 tire is 34.8 inches tall (884 mm), calculated from the size. It is 12.0 inches wide with 8.4 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 305/70R18 mean?
- 305/70R18 means a tire 305 mm wide, with sidewalls 70% as tall as the tire is wide (214 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 305/70R18 tire make?
- About 579 revolutions per mile, based on a circumference of 109.4 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 305/70R18 tire?
- Roughly 8.0" to 9.5". Check the tire maker's approved rim range for the exact model before buying wheels.
- Can I use 285/75R18 instead of 305/70R18?
- 285/75R18 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.