285/30R18 tire size
285/30R18 is a metric size: 24.7" tall, 11.2" wide, on a 18" rim — about a 24.5x11.00R18. The sidewall is 3.4" and the tire turns 815 times per mile.
285/30R18 specs
| Overall diameter (height) | 24.73" · 628 mm |
|---|---|
| Section width | 11.22" · 285 mm |
| Sidewall height | 3.37" · 86 mm (30% of width) |
| Rim diameter | 18" |
| Circumference | 77.70" · 1.974 m |
| Revolutions per mile | 815 (507 per km) |
| Inch (flotation) equivalent | 24.5x11.00R18 |
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 | |
|---|---|---|---|---|---|
| 245/40R18 common | 25.72" | +3.98% | -40 mm | 62.4 mph | compare → |
| 225/40R18 common | 25.09" | +1.43% | -60 mm | 60.9 mph | compare → |
| 235/40R18 common | 25.40" | +2.71% | -50 mm | 61.6 mph | compare → |
| 255/35R18 common | 25.03" | +1.19% | -30 mm | 60.7 mph | compare → |
| 275/35R18 common | 25.58" | +3.42% | -10 mm | 62.1 mph | compare → |
| 265/35R18 common | 25.30" | +2.31% | -20 mm | 61.4 mph | compare → |
| 215/45R18 common | 25.62" | +3.58% | -70 mm | 62.1 mph | compare → |
| 245/35R18 common | 24.75" | +0.08% | -40 mm | 60.0 mph | compare → |
| 215/40R18 | 24.77" | +0.16% | -70 mm | 60.1 mph | compare → |
| 285/35R18 | 25.85" | +4.54% | 0 mm | 62.7 mph | compare → |
| 295/30R18 | 24.97" | +0.96% | +10 mm | 60.6 mph | compare → |
| 315/30R18 | 25.44" | +2.87% | +30 mm | 61.7 mph | compare → |
| 205/40R18 | 24.46" | -1.11% | -80 mm | 59.3 mph | compare → |
| 335/30R18 | 25.91" | +4.78% | +50 mm | 62.9 mph | compare → |
| 225/35R18 | 24.20" | -2.15% | -60 mm | 58.7 mph | calculate → |
| 215/35R18 | 23.93" | -3.26% | -70 mm | 58.0 mph | calculate → |
| 235/35R18 | 24.48" | -1.03% | -50 mm | 59.4 mph | calculate → |
| 305/30R18 | 25.20" | +1.91% | +20 mm | 61.1 mph | calculate → |
| 155/60R18 | 25.32" | +2.39% | -130 mm | 61.4 mph | calculate → |
| 205/35R18 | 23.65" | -4.38% | -80 mm | 57.4 mph | calculate → |
| 235/30R18 | 23.55" | -4.78% | -50 mm | 57.1 mph | calculate → |
| 205/45R18 | 25.26" | +2.15% | -80 mm | 61.3 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 | |
|---|---|---|---|---|---|
| 225/45R17 common | 24.97" | +0.97% | -60 mm | 60.6 mph | compare → |
| 215/45R17 common | 24.62" | -0.46% | -70 mm | 59.7 mph | compare → |
| 245/40R17 common | 24.72" | -0.06% | -40 mm | 60.0 mph | compare → |
| 275/35R17 | 24.58" | -0.62% | -10 mm | 59.6 mph | calculate → |
| 245/30R19 | 24.79" | +0.22% | -40 mm | 60.1 mph | calculate → |
| 295/25R19 | 24.81" | +0.30% | +10 mm | 60.2 mph | calculate → |
| 235/30R19 | 24.55" | -0.73% | -50 mm | 59.6 mph | calculate → |
| 215/35R19 | 24.93" | +0.78% | -70 mm | 60.5 mph | calculate → |
Try another size against 285/30R18
Questions
What size is 285/30R18 in inches?
285/30R18 is about 24.7" tall and 11.2" wide on a 18-inch rim — roughly a 24.5x11.00R18 in inch sizing.
What does 285/30R18 mean?
285 mm section width, sidewall 30% of the width (3.37"), radial construction, 18-inch rim.
What tire sizes are equivalent to 285/30R18?
On the same 18" rim, within 3% of the diameter: 245/35R18 (+0.08%), 215/40R18 (+0.16%), 295/30R18 (+0.96%), 235/35R18 (-1.03%), 205/40R18 (-1.11%), 255/35R18 (+1.19%).
How many revolutions per mile does a 285/30R18 tire make?
About 815 revolutions per mile (circumference 77.7").
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.