245/55R18 tire size
245/55R18 is a metric size: 28.6" tall, 9.6" wide, on a 18" rim — about a 28.5x9.50R18. The sidewall is 5.3" and the tire turns 705 times per mile.
245/55R18 specs
| Overall diameter (height) | 28.61" · 727 mm |
|---|---|
| Section width | 9.65" · 245 mm |
| Sidewall height | 5.31" · 135 mm (55% of width) |
| Rim diameter | 18" |
| Circumference | 89.88" · 2.283 m |
| Revolutions per mile | 705 (438 per km) |
| Inch (flotation) equivalent | 28.5x9.50R18 |
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" | +1.72% | -10 mm | 61.0 mph | compare → |
| 235/50R18 common | 27.25" | -4.75% | -10 mm | 57.2 mph | compare → |
| 235/55R18 common | 28.18" | -1.51% | -10 mm | 59.1 mph | compare → |
| 225/60R18 common | 28.63" | +0.07% | -20 mm | 60.0 mph | compare → |
| 245/60R18 common | 29.57" | +3.37% | 0 mm | 62.0 mph | compare → |
| 225/55R18 common | 27.74" | -3.03% | -20 mm | 58.2 mph | compare → |
| 255/55R18 common | 29.04" | +1.51% | +10 mm | 60.9 mph | compare → |
| 235/65R18 common | 30.03" | +4.95% | -10 mm | 63.0 mph | compare → |
| 245/50R18 common | 27.65" | -3.37% | 0 mm | 58.0 mph | compare → |
| 215/55R18 common | 27.31" | -4.54% | -30 mm | 57.3 mph | compare → |
| 275/45R18 | 27.74" | -3.03% | +30 mm | 58.2 mph | compare → |
| 265/45R18 | 27.39" | -4.27% | +20 mm | 57.4 mph | compare → |
| 295/40R18 | 27.29" | -4.61% | +50 mm | 57.2 mph | compare → |
| 345/35R18 | 27.51" | -3.85% | +100 mm | 57.7 mph | calculate → |
| 295/45R18 | 28.45" | -0.55% | +50 mm | 59.7 mph | calculate → |
| 255/50R18 | 28.04" | -2.00% | +10 mm | 58.8 mph | calculate → |
| 155/90R18 | 28.98" | +1.31% | -90 mm | 60.8 mph | calculate → |
| 315/40R18 | 27.92" | -2.41% | +70 mm | 58.6 mph | calculate → |
| 305/45R18 | 28.81" | +0.69% | +60 mm | 60.4 mph | calculate → |
| 155/85R18 | 28.37" | -0.83% | -90 mm | 59.5 mph | calculate → |
| 215/60R18 | 28.16" | -1.58% | -30 mm | 59.1 mph | calculate → |
| 285/50R18 | 29.22" | +2.13% | +40 mm | 61.3 mph | calculate → |
| 305/40R18 | 27.61" | -3.51% | +60 mm | 57.9 mph | calculate → |
| 165/90R18 | 29.69" | +3.78% | -80 mm | 62.3 mph | calculate → |
| 285/45R18 | 28.10" | -1.79% | +40 mm | 58.9 mph | calculate → |
| 28x12.00R18 | 28.00" | -2.13% | +60 mm | 58.7 mph | calculate → |
| 145/85R18 | 27.70" | -3.16% | -100 mm | 58.1 mph | calculate → |
| 325/45R18 | 29.52" | +3.16% | +80 mm | 61.9 mph | calculate → |
| 275/55R18 | 29.91" | +4.54% | +30 mm | 62.7 mph | calculate → |
| 265/50R18 | 28.43" | -0.62% | +20 mm | 59.6 mph | calculate → |
| 28x10.00R18 | 28.00" | -2.13% | +9 mm | 58.7 mph | calculate → |
| 265/55R18 | 29.48" | +3.03% | +20 mm | 61.8 mph | calculate → |
| 225/65R18 | 29.52" | +3.16% | -20 mm | 61.9 mph | calculate → |
| 205/60R18 | 27.69" | -3.23% | -40 mm | 58.1 mph | calculate → |
| 195/60R18 | 27.21" | -4.89% | -50 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 | |
|---|---|---|---|---|---|
| 225/65R17 common | 28.52" | -0.33% | -20 mm | 59.8 mph | compare → |
| 225/55R19 common | 28.74" | +0.47% | -20 mm | 60.3 mph | compare → |
| 245/50R19 common | 28.65" | +0.12% | 0 mm | 60.1 mph | compare → |
| 275/45R19 | 28.74" | +0.47% | +30 mm | 60.3 mph | compare → |
| 265/45R19 | 28.39" | -0.77% | +20 mm | 59.5 mph | calculate → |
| 165/90R17 | 28.69" | +0.29% | -80 mm | 60.2 mph | calculate → |
| 215/70R17 | 28.85" | +0.84% | -30 mm | 60.5 mph | calculate → |
| 345/35R19 | 28.51" | -0.36% | +100 mm | 59.8 mph | calculate → |
| 155/80R19 | 28.76" | +0.54% | -90 mm | 60.3 mph | calculate → |
| 245/60R17 | 28.57" | -0.12% | 0 mm | 59.9 mph | calculate → |
Try another size against 245/55R18
Questions
What size is 245/55R18 in inches?
245/55R18 is about 28.6" tall and 9.6" wide on a 18-inch rim — roughly a 28.5x9.50R18 in inch sizing.
What does 245/55R18 mean?
245 mm section width, sidewall 55% of the width (5.31"), radial construction, 18-inch rim.
What tire sizes are equivalent to 245/55R18?
On the same 18" rim, within 3% of the diameter: 225/60R18 (+0.07%), 295/45R18 (-0.55%), 265/50R18 (-0.62%), 305/45R18 (+0.69%), 155/85R18 (-0.83%), 155/90R18 (+1.31%).
How many revolutions per mile does a 245/55R18 tire make?
About 705 revolutions per mile (circumference 89.9").
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.