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305/60R18 tire size in inches
305/60R18 is 32.41" tall and 12.01" wide, and fits a 18" rim. In flotation (inch) sizing that is roughly 32.4x12.0R18.
305/60R18 dimensions
| Measurement | Inches | Metric |
|---|---|---|
| Overall diameter (height) | 32.41" | 823 mm |
| Section width | 12.01" | 305 mm |
| Sidewall height | 7.20" | 183.0 mm |
| Rim diameter | 18" | 457.2 mm |
| Circumference | 101.8" | 2586 mm |
| Revolutions per mile | 622 | |
| Aspect ratio | 60% (sidewall is 60% of the width) | |
Drawn to scale
Among the 122 sizes for 18" wheels on this site, 305/60R18 is #76 by height (shortest: 245/35R18, tallest: 340/80R18).
305/60R18 against the most popular 18" sizes
| Popular size | Height | Width | Sidewall | Speedo at true 60 |
|---|---|---|---|---|
| 275/70R18 | +0.75" (+2.31%) | -1.18" | +0.38" | 58.6 mph |
| 275/65R18 | -0.34" (-1.05%) | -1.18" | -0.16" | 60.6 mph |
| 295/70R18 | +1.85" (+5.71%) | -0.40" | +0.93" | 56.8 mph |
| 285/65R18 | +0.18" (+0.56%) | -0.79" | +0.09" | 59.7 mph |
| 305/70R18 | +2.40" (+7.41%) | 0.00" | +1.21" | 55.9 mph |
How the 305/60R18 numbers are worked out
The size code reads as 305 mm section width, 60% aspect ratio, R for radial construction and 18-inch wheel.
- Sidewall = 305 × 60% = 183.0 mm = 7.20"
- Diameter = 18" + 2 × 7.20" = 32.41"
- Circumference = π × 32.41" = 101.8"
- Revs per mile = 63,360" ÷ 101.8" = 622
Sizes that can replace 305/60R18 on a 18" wheel
Within 3% of 32.41". Last column: speedometer reading at a true 60 mph.
| Size | Diameter | Width | Difference | Speedo at true 60 mph |
|---|---|---|---|---|
| 245/75R18 | 32.47" | 9.65" | +0.19% | 59.9 mph |
| 280/65R18 | 32.33" | 11.02" | -0.25% | 60.1 mph |
| 285/65R18 | 32.59" | 11.22" | +0.56% | 59.7 mph |
| 265/70R18 | 32.61" | 10.43" | +0.62% | 59.6 mph |
| 275/65R18 | 32.07" | 10.83" | -1.05% | 60.6 mph |
| 325/55R18 | 32.07" | 12.80" | -1.05% | 60.6 mph |
| 255/70R18 | 32.06" | 10.04" | -1.08% | 60.7 mph |
| 375/50R18 | 32.76" | 14.76" | +1.08% | 59.4 mph |
| 235/80R18 | 32.80" | 9.25" | +1.2% | 59.3 mph |
| 270/70R18 | 32.88" | 10.63" | +1.45% | 59.1 mph |
| 295/60R18 | 31.94" | 11.61" | -1.45% | 60.9 mph |
| 315/60R18 | 32.88" | 12.40" | +1.45% | 59.1 mph |
One size wider or narrower
- Narrower: 295/60R18 — 11.61" wide, 31.94" tall
- Wider: 315/60R18 — 12.40" wide, 32.88" tall
Same height on a different wheel size
- 295/75R15 15" (+0.03%)
- 315/70R15 15" (-0.15%)
- 265/85R15 15" (+1.02%)
- 255/85R15 15" (-1.05%)
- 285/75R15 15" (-1.79%)
- 305/70R15 15" (-1.85%)
- 305/75R15 15" (+1.85%)
- 245/85R16 16" (-0.03%)
- 280/75R16 16" (+0.4%)
- 295/70R16 16" (-0.46%)
Questions about 305/60R18
How tall is a 305/60R18 tire in inches?
A 305/60R18 tire is 32.41 inches (823 mm) tall: the 18-inch rim plus two sidewalls of 7.20 inches each.
Is 305/60R18 a 32 inch tire?
Yes. At 32.41 inches tall it is commonly called a 32-inch tire.
How many revolutions per mile does a 305/60R18 make?
About 622 revolutions per mile, based on a calculated circumference of 101.8 inches.
What size can replace 305/60R18?
245/75R18 is the closest match on a 18" rim (+0.19% height). Check load index, speed rating and clearance first.
Compare 305/60R18 against any other size with the tire size calculator.