285/50R18 tire size
285/50R18 is a metric size: 29.2" tall, 11.2" wide, on a 18" rim — about a 29x11.00R18. The sidewall is 5.6" and the tire turns 690 times per mile.
285/50R18 specs
| Overall diameter (height) | 29.22" · 742 mm |
|---|---|
| Section width | 11.22" · 285 mm |
| Sidewall height | 5.61" · 143 mm (50% of width) |
| Rim diameter | 18" |
| Circumference | 91.80" · 2.332 m |
| Revolutions per mile | 690 (429 per km) |
| Inch (flotation) equivalent | 29x11.00R18 |
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" | -0.40% | -50 mm | 59.8 mph | calculate → |
| 235/55R18 common | 28.18" | -3.57% | -50 mm | 57.9 mph | calculate → |
| 265/60R18 common | 30.52" | +4.45% | -20 mm | 62.7 mph | calculate → |
| 225/60R18 common | 28.63" | -2.02% | -60 mm | 58.8 mph | calculate → |
| 245/60R18 common | 29.57" | +1.21% | -40 mm | 60.7 mph | calculate → |
| 255/55R18 common | 29.04" | -0.61% | -30 mm | 59.6 mph | calculate → |
| 235/65R18 common | 30.03" | +2.76% | -50 mm | 61.7 mph | calculate → |
| 255/60R18 | 30.05" | +2.83% | -30 mm | 61.7 mph | calculate → |
| 245/55R18 | 28.61" | -2.09% | -40 mm | 58.7 mph | calculate → |
| 295/45R18 | 28.45" | -2.63% | +10 mm | 58.4 mph | calculate → |
| 255/50R18 | 28.04" | -4.04% | -30 mm | 57.6 mph | calculate → |
| 155/90R18 | 28.98" | -0.81% | -130 mm | 59.5 mph | calculate → |
| 315/40R18 | 27.92" | -4.45% | +30 mm | 57.3 mph | calculate → |
| 305/45R18 | 28.81" | -1.41% | +20 mm | 59.2 mph | calculate → |
| 165/90R18 | 29.69" | +1.62% | -120 mm | 61.0 mph | calculate → |
| 155/85R18 | 28.37" | -2.90% | -130 mm | 58.3 mph | calculate → |
| 215/60R18 | 28.16" | -3.64% | -70 mm | 57.8 mph | calculate → |
| 325/45R18 | 29.52" | +1.01% | +40 mm | 60.6 mph | calculate → |
| 275/55R18 | 29.91" | +2.36% | -10 mm | 61.4 mph | calculate → |
| 285/45R18 | 28.10" | -3.84% | 0 mm | 57.7 mph | calculate → |
| 285/55R18 | 30.34" | +3.84% | 0 mm | 62.3 mph | calculate → |
| 175/90R18 | 30.40" | +4.04% | -110 mm | 62.4 mph | calculate → |
| 28x12.00R18 | 28.00" | -4.18% | +20 mm | 57.5 mph | calculate → |
| 245/65R18 | 30.54" | +4.51% | -40 mm | 62.7 mph | calculate → |
| 265/55R18 | 29.48" | +0.88% | -20 mm | 60.5 mph | calculate → |
| 225/65R18 | 29.52" | +1.01% | -60 mm | 60.6 mph | calculate → |
| 265/50R18 | 28.43" | -2.69% | -20 mm | 58.4 mph | calculate → |
| 28x10.00R18 | 28.00" | -4.18% | -31 mm | 57.5 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 | |
|---|---|---|---|---|---|
| 235/55R19 common | 29.18" | -0.15% | -50 mm | 59.9 mph | calculate → |
| 235/65R17 common | 29.03" | -0.66% | -50 mm | 59.6 mph | calculate → |
| 255/50R19 common | 29.04" | -0.62% | -30 mm | 59.6 mph | calculate → |
| 265/50R19 common | 29.43" | +0.73% | -20 mm | 60.4 mph | calculate → |
| 255/60R17 | 29.05" | -0.59% | -30 mm | 59.6 mph | calculate → |
| 285/45R19 | 29.10" | -0.42% | 0 mm | 59.7 mph | calculate → |
| 295/45R19 | 29.45" | +0.79% | +10 mm | 60.5 mph | calculate → |
| 175/90R17 | 29.40" | +0.62% | -110 mm | 60.4 mph | calculate → |
| 225/70R17 | 29.40" | +0.62% | -60 mm | 60.4 mph | calculate → |
Try another size against 285/50R18
Questions
What size is 285/50R18 in inches?
285/50R18 is about 29.2" tall and 11.2" wide on a 18-inch rim — roughly a 29x11.00R18 in inch sizing.
What does 285/50R18 mean?
285 mm section width, sidewall 50% of the width (5.61"), radial construction, 18-inch rim.
What tire sizes are equivalent to 285/50R18?
On the same 18" rim, within 3% of the diameter: 235/60R18 (-0.40%), 255/55R18 (-0.61%), 155/90R18 (-0.81%), 265/55R18 (+0.88%), 225/65R18 (+1.01%), 325/45R18 (+1.01%).
How many revolutions per mile does a 285/50R18 tire make?
About 690 revolutions per mile (circumference 91.8").
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.