255/70R18 tire size
255/70R18 is a metric size: 32.1" tall, 10.0" wide, on a 18" rim — about a 32x10.00R18. The sidewall is 7.0" and the tire turns 629 times per mile.
255/70R18 specs
| Overall diameter (height) | 32.06" · 814 mm |
|---|---|
| Section width | 10.04" · 255 mm |
| Sidewall height | 7.03" · 179 mm (70% of width) |
| Rim diameter | 18" |
| Circumference | 100.70" · 2.558 m |
| Revolutions per mile | 629 (391 per km) |
| Inch (flotation) equivalent | 32x10.00R18 |
Equivalent sizes on a 18" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 275/65R18 common | 32.07" | +0.06% | +20 mm | 60.0 mph | compare → |
| 265/60R18 common | 30.52" | -4.79% | +10 mm | 57.1 mph | compare → |
| 275/70R18 common | 33.16" | +3.44% | +20 mm | 62.1 mph | compare → |
| 265/65R18 common | 31.56" | -1.54% | +10 mm | 59.1 mph | compare → |
| 265/70R18 common | 32.61" | +1.72% | +10 mm | 61.0 mph | compare → |
| 255/65R18 common | 31.05" | -3.13% | 0 mm | 58.1 mph | compare → |
| 285/65R18 common | 32.59" | +1.66% | +30 mm | 61.0 mph | compare → |
| 33x12.50R18 | 33.00" | +2.95% | +63 mm | 61.8 mph | compare → |
| 285/60R18 | 31.46" | -1.84% | +30 mm | 58.9 mph | compare → |
| 305/65R18 | 33.61" | +4.85% | +50 mm | 62.9 mph | compare → |
| 275/60R18 | 30.99" | -3.32% | +20 mm | 58.0 mph | compare → |
| 305/60R18 | 32.41" | +1.11% | +50 mm | 60.7 mph | compare → |
| 325/60R18 | 33.35" | +4.05% | +70 mm | 62.4 mph | compare → |
| 245/75R18 | 32.47" | +1.29% | -10 mm | 60.8 mph | calculate → |
| 295/65R18 | 33.10" | +3.25% | +40 mm | 62.0 mph | calculate → |
| 245/70R18 | 31.50" | -1.72% | -10 mm | 59.0 mph | calculate → |
| 235/80R18 | 32.80" | +2.33% | -20 mm | 61.4 mph | calculate → |
| 33x11.50R18 | 33.00" | +2.95% | +37 mm | 61.8 mph | calculate → |
| 33x13.50R18 | 33.00" | +2.95% | +88 mm | 61.8 mph | calculate → |
| 33x13.00R18 | 33.00" | +2.95% | +75 mm | 61.8 mph | calculate → |
| 235/70R18 | 30.95" | -3.44% | -20 mm | 57.9 mph | calculate → |
| 245/65R18 | 30.54" | -4.73% | -10 mm | 57.2 mph | calculate → |
| 33x10.50R18 | 33.00" | +2.95% | +12 mm | 61.8 mph | calculate → |
Plus / minus sizing: 17" and 19" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 235/80R17 common | 31.80" | -0.79% | -20 mm | 59.5 mph | compare → |
| 255/75R17 | 32.06" | +0.01% | 0 mm | 60.0 mph | compare → |
| 275/70R17 | 32.16" | +0.32% | +20 mm | 60.2 mph | compare → |
| 255/65R19 | 32.05" | -0.01% | 0 mm | 60.0 mph | calculate → |
| 32x11.50R17 | 32.00" | -0.17% | +37 mm | 59.9 mph | calculate → |
| 315/60R17 | 31.88" | -0.54% | +60 mm | 59.7 mph | calculate → |
| 32x10.50R17 | 32.00" | -0.17% | +12 mm | 59.9 mph | calculate → |
Try another size against 255/70R18
Questions
What size is 255/70R18 in inches?
255/70R18 is about 32.1" tall and 10.0" wide on a 18-inch rim — roughly a 32x10.00R18 in inch sizing.
What does 255/70R18 mean?
255 mm section width, sidewall 70% of the width (7.03"), radial construction, 18-inch rim.
What tire sizes are equivalent to 255/70R18?
On the same 18" rim, within 3% of the diameter: 275/65R18 (+0.06%), 305/60R18 (+1.11%), 245/75R18 (+1.29%), 265/65R18 (-1.54%), 285/65R18 (+1.66%), 245/70R18 (-1.72%).
How many revolutions per mile does a 255/70R18 tire make?
About 629 revolutions per mile (circumference 100.7").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.