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305/70R18 tire size in inches
305/70R18 is 34.81" tall and 12.01" wide, and fits a 18" rim. In flotation (inch) sizing that is roughly 34.8x12.0R18.
305/70R18 dimensions
| Measurement | Inches | Metric |
|---|---|---|
| Overall diameter (height) | 34.81" | 884 mm |
| Section width | 12.01" | 305 mm |
| Sidewall height | 8.41" | 213.5 mm |
| Rim diameter | 18" | 457.2 mm |
| Circumference | 109.4" | 2778 mm |
| Revolutions per mile | 579 | |
| Aspect ratio | 70% (sidewall is 70% of the width) | |
Drawn to scale
Among the 122 sizes for 18" wheels on this site, 305/70R18 is #101 by height (shortest: 245/35R18, tallest: 340/80R18).
What people compare 305/70R18 with
Real comparisons drivers search for, worked out against 305/70R18:
| Compared size | Height | Width | Sidewall | Speedo at true 60 |
|---|---|---|---|---|
| 295/70R18 | -0.55" (-1.58%) | -0.40" | -0.28" | 61 mph |
| 285/75R18 | +0.02" (+0.06%) | -0.79" | +0.01" | 60 mph |
| 275/70R18 | -1.65" (-4.74%) | -1.18" | -0.83" | 63 mph |
How the 305/70R18 numbers are worked out
The size code reads as 305 mm section width, 70% aspect ratio, R for radial construction and 18-inch wheel.
- Sidewall = 305 × 70% = 213.5 mm = 8.41"
- Diameter = 18" + 2 × 8.41" = 34.81"
- Circumference = π × 34.81" = 109.4"
- Revs per mile = 63,360" ÷ 109.4" = 579
Sizes that can replace 305/70R18 on a 18" wheel
Within 3% of 34.81". Last column: speedometer reading at a true 60 mph.
| Size | Diameter | Width | Difference | Speedo at true 60 mph |
|---|---|---|---|---|
| 285/75R18 | 34.83" | 11.22" | +0.06% | 60 mph |
| 265/80R18 | 34.69" | 10.43" | -0.34% | 60.2 mph |
| 325/65R18 | 34.63" | 12.80" | -0.52% | 60.3 mph |
| 255/85R18 | 35.07" | 10.04" | +0.75% | 59.6 mph |
| 280/75R18 | 34.54" | 11.02" | -0.78% | 60.5 mph |
| 335/65R18 | 35.15" | 13.19" | +0.98% | 59.4 mph |
| 275/80R18 | 35.32" | 10.83" | +1.47% | 59.1 mph |
| 295/70R18 | 34.26" | 11.61" | -1.58% | 61 mph |
| 315/70R18 | 35.36" | 12.40" | +1.58% | 59.1 mph |
| 275/75R18 | 34.24" | 10.83" | -1.64% | 61 mph |
| 295/75R18 | 35.42" | 11.61" | +1.75% | 59 mph |
| 315/65R18 | 34.12" | 12.40" | -1.98% | 61.2 mph |
One size wider or narrower
Same height on a different wheel size
- 325/75R15 15" (-1.78%)
- 315/75R16 16" (-0.6%)
- 295/80R16 16" (-0.66%)
- 285/85R16 16" (+0.75%)
- 325/75R16 16" (+1.09%)
- 375/65R16 16" (+1.09%)
- 275/85R16 16" (-1.15%)
- 305/80R16 16" (+1.15%)
- 265/85R17 17" (-0.2%)
- 325/70R17 17" (+0.29%)
Questions about 305/70R18
How tall is a 305/70R18 tire in inches?
A 305/70R18 tire is 34.81 inches (884 mm) tall: the 18-inch rim plus two sidewalls of 8.41 inches each.
Is 305/70R18 a 35 inch tire?
Yes. At 34.81 inches tall it is commonly called a 35-inch tire.
How many revolutions per mile does a 305/70R18 make?
About 579 revolutions per mile, based on a calculated circumference of 109.4 inches.
What size can replace 305/70R18?
285/75R18 is the closest match on a 18" rim (+0.06% height). Check load index, speed rating and clearance first.
Compare 305/70R18 against any other size with the tire size calculator.