255/50R18 tire size
255/50R18 is a metric size: 28.0" tall, 10.0" wide, on a 18" rim — about a 28x10.00R18. The sidewall is 5.0" and the tire turns 719 times per mile.
255/50R18 specs
| Overall diameter (height) | 28.04" · 712 mm |
|---|---|
| Section width | 10.04" · 255 mm |
| Sidewall height | 5.02" · 127 mm (50% of width) |
| Rim diameter | 18" |
| Circumference | 88.09" · 2.237 m |
| Revolutions per mile | 719 (447 per km) |
| Inch (flotation) equivalent | 28x10.00R18 |
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 | |
|---|---|---|---|---|---|
| 235/60R18 common | 29.10" | +3.79% | -20 mm | 62.3 mph | calculate → |
| 245/45R18 common | 26.68" | -4.84% | -10 mm | 57.1 mph | calculate → |
| 235/50R18 common | 27.25" | -2.81% | -20 mm | 58.3 mph | calculate → |
| 235/55R18 common | 28.18" | +0.49% | -20 mm | 60.3 mph | calculate → |
| 225/60R18 common | 28.63" | +2.11% | -30 mm | 61.3 mph | calculate → |
| 225/50R18 common | 26.86" | -4.21% | -30 mm | 57.5 mph | calculate → |
| 225/55R18 common | 27.74" | -1.05% | -30 mm | 59.4 mph | calculate → |
| 255/55R18 common | 29.04" | +3.58% | 0 mm | 62.1 mph | calculate → |
| 245/50R18 common | 27.65" | -1.40% | -10 mm | 59.2 mph | calculate → |
| 255/45R18 common | 27.04" | -3.58% | 0 mm | 57.9 mph | calculate → |
| 215/55R18 common | 27.31" | -2.60% | -40 mm | 58.4 mph | calculate → |
| 275/40R18 common | 26.66" | -4.91% | +20 mm | 57.1 mph | calculate → |
| 245/55R18 | 28.61" | +2.04% | -10 mm | 61.2 mph | calculate → |
| 275/45R18 | 27.74" | -1.05% | +20 mm | 59.4 mph | calculate → |
| 265/45R18 | 27.39" | -2.32% | +10 mm | 58.6 mph | calculate → |
| 295/40R18 | 27.29" | -2.67% | +40 mm | 58.4 mph | calculate → |
| 285/40R18 | 26.98" | -3.79% | +30 mm | 57.7 mph | calculate → |
| 345/35R18 | 27.51" | -1.90% | +90 mm | 58.9 mph | calculate → |
| 295/45R18 | 28.45" | +1.47% | +40 mm | 60.9 mph | calculate → |
| 315/40R18 | 27.92" | -0.42% | +60 mm | 59.7 mph | calculate → |
| 155/90R18 | 28.98" | +3.37% | -100 mm | 62.0 mph | calculate → |
| 215/60R18 | 28.16" | +0.42% | -40 mm | 60.3 mph | calculate → |
| 155/85R18 | 28.37" | +1.19% | -100 mm | 60.7 mph | calculate → |
| 305/40R18 | 27.61" | -1.54% | +50 mm | 59.1 mph | calculate → |
| 305/45R18 | 28.81" | +2.74% | +50 mm | 61.6 mph | calculate → |
| 285/50R18 | 29.22" | +4.21% | +30 mm | 62.5 mph | calculate → |
| 28x12.00R18 | 28.00" | -0.14% | +50 mm | 59.9 mph | calculate → |
| 285/45R18 | 28.10" | +0.21% | +30 mm | 60.1 mph | calculate → |
| 145/85R18 | 27.70" | -1.19% | -110 mm | 59.3 mph | calculate → |
| 145/80R18 | 27.13" | -3.23% | -110 mm | 58.1 mph | calculate → |
| 165/70R18 | 27.09" | -3.37% | -90 mm | 58.0 mph | calculate → |
| 325/35R18 | 26.96" | -3.86% | +70 mm | 57.7 mph | calculate → |
| 28x10.00R18 | 28.00" | -0.14% | -1 mm | 59.9 mph | calculate → |
| 205/60R18 | 27.69" | -1.26% | -50 mm | 59.2 mph | calculate → |
| 265/50R18 | 28.43" | +1.40% | +10 mm | 60.8 mph | calculate → |
| 195/60R18 | 27.21" | -2.95% | -60 mm | 58.2 mph | calculate → |
| 315/35R18 | 26.68" | -4.84% | +60 mm | 57.1 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 | |
|---|---|---|---|---|---|
| 255/45R19 common | 28.04" | -0.01% | 0 mm | 60.0 mph | calculate → |
| 235/60R17 common | 28.10" | +0.22% | -20 mm | 60.1 mph | calculate → |
| 215/65R17 common | 28.00" | -0.13% | -40 mm | 59.9 mph | calculate → |
| 235/50R19 common | 28.25" | +0.76% | -20 mm | 60.5 mph | calculate → |
| 285/40R19 | 27.98" | -0.22% | +30 mm | 59.9 mph | calculate → |
| 295/40R19 | 28.29" | +0.90% | +40 mm | 60.5 mph | calculate → |
| 255/55R17 | 28.04" | +0.01% | 0 mm | 60.0 mph | calculate → |
| 155/90R17 | 27.98" | -0.20% | -100 mm | 59.9 mph | calculate → |
| 305/45R17 | 27.81" | -0.83% | +50 mm | 59.5 mph | calculate → |
| 28x6.00R17 | 28.00" | -0.14% | -103 mm | 59.9 mph | calculate → |
| 275/50R17 | 27.83" | -0.76% | +20 mm | 59.5 mph | calculate → |
| 145/80R19 | 28.13" | +0.34% | -110 mm | 60.2 mph | calculate → |
| 345/40R17 | 27.87" | -0.62% | +90 mm | 59.6 mph | calculate → |
| 225/50R19 | 27.86" | -0.65% | -30 mm | 59.6 mph | calculate → |
Try another size against 255/50R18
Questions
What size is 255/50R18 in inches?
255/50R18 is about 28.0" tall and 10.0" wide on a 18-inch rim — roughly a 28x10.00R18 in inch sizing.
What does 255/50R18 mean?
255 mm section width, sidewall 50% of the width (5.02"), radial construction, 18-inch rim.
What tire sizes are equivalent to 255/50R18?
On the same 18" rim, within 3% of the diameter: 28x10.00R18 (-0.14%), 28x12.00R18 (-0.14%), 285/45R18 (+0.21%), 315/40R18 (-0.42%), 215/60R18 (+0.42%), 235/55R18 (+0.49%).
How many revolutions per mile does a 255/50R18 tire make?
About 719 revolutions per mile (circumference 88.1").
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.