305/65R18 tire size in inches
A 305/65R18 tire measures
33.6" tall × 12.0" wide
7.81" sidewall on a 18" wheel. 600 revolutions per mile.
305/65R18 means a tire 305 mm wide, with sidewalls 65% as tall as the tire is wide (198 mm), radial construction (R), for a 18 inch wheel.
305/65R18 specs
| Overall diameter (height) | 33.61 inches (854 mm) |
|---|---|
| Section width | 12.01 inches (305 mm) |
| Sidewall height | 7.81 inches (198 mm) |
| Wheel (rim) diameter | 18 inches |
| Circumference | 105.6 inches (2,682 mm) |
| Revolutions per mile | 600 |
| Revolutions per kilometer | 373 |
| Approximate rim width | 8.0" to 9.5" |
| In inches (flotation style) | 33.6x12.0R18 |
| Aspect ratio | 65% |
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 305/65R18 on a 18" wheel
These 18" sizes are within 3% of 305/65R18's overall diameter, the range most tire shops treat as interchangeable.
| Size | Diameter | Width | Difference | Real speed at 60 | |
|---|---|---|---|---|---|
| 265/75R18 | 33.65" | 10.43" | +0.1% | 60.1 mph | Compare |
| 285/70R18 | 33.71" | 11.22" | +0.3% | 60.2 mph | Compare |
| 335/60R18 | 33.83" | 13.19" | +0.6% | 60.4 mph | Compare |
| 325/60R18 | 33.35" | 12.80" | −0.8% | 59.5 mph | Compare |
| 275/70R18 | 33.16" | 10.83" | −1.3% | 59.2 mph | Compare |
| 315/65R18 | 34.12" | 12.40" | +1.5% | 60.9 mph | Compare |
| 295/65R18 | 33.10" | 11.61" | −1.5% | 59.1 mph | Compare |
| 255/75R18 | 33.06" | 10.04" | −1.6% | 59.0 mph | Compare |
| 33x12.50R18 | 33.00" | 12.50" | −1.8% | 58.9 mph | Compare |
| 275/75R18 | 34.24" | 10.83" | +1.9% | 61.1 mph | Compare |
| 295/70R18 | 34.26" | 11.61" | +1.9% | 61.2 mph | Compare |
| 315/60R18 | 32.88" | 12.40" | −2.2% | 58.7 mph | Compare |
Same height on other wheel sizes (plus and minus sizing)
| Size | Wheel | Diameter | Difference | |
|---|---|---|---|---|
| 295/50R22 | 22" | 33.61" | 0.0% | Compare |
| 305/40R24 | 24" | 33.61" | 0.0% | Compare |
| 285/65R19 | 19" | 33.59" | −0.1% | Compare |
| 345/50R20 | 20" | 33.58" | −0.1% | Compare |
| 315/55R20 | 20" | 33.64" | +0.1% | Compare |
| 355/45R21 | 21" | 33.58" | −0.1% | Compare |
| 265/65R20 | 20" | 33.56" | −0.1% | Compare |
| 325/45R22 | 22" | 33.52" | −0.3% | Compare |
| 335/55R19 | 19" | 33.51" | −0.3% | Compare |
| 345/35R24 | 24" | 33.51" | −0.3% | Compare |
| 265/85R16 | 16" | 33.74" | +0.4% | Compare |
| 265/55R22 | 22" | 33.48" | −0.4% | Compare |
One size up or down
- 295/65R18narrower: 33.1" × 11.6"
- 315/65R18wider: 34.1" × 12.4"
- 305/60R18lower profile: 32.4" × 12.0"
- 305/70R18taller sidewall: 34.8" × 12.0"
Compare 305/65R18 with another size
Questions
- How tall is a 305/65R18 tire?
- A 305/65R18 tire is 33.6 inches tall (854 mm), calculated from the size. It is 12.0 inches wide with 7.8 inches sidewalls. Real tires vary by a few tenths of an inch between brands and tread patterns.
- What does 305/65R18 mean?
- 305/65R18 means a tire 305 mm wide, with sidewalls 65% as tall as the tire is wide (198 mm), radial construction (R), for a 18 inch wheel.
- How many revolutions per mile does a 305/65R18 tire make?
- About 600 revolutions per mile, based on a circumference of 105.6 inches. Under load the tire flattens slightly, so the maker's published figure is usually a little higher.
- What rim width fits a 305/65R18 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 265/75R18 instead of 305/65R18?
- 265/75R18 is +0.04 inches (+0.1%) 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.