235/55R18 tire size
235/55R18 is a metric size: 28.2" tall, 9.3" wide, on a 18" rim — about a 28x9.50R18. The sidewall is 5.1" and the tire turns 716 times per mile.
235/55R18 specs
| Overall diameter (height) | 28.18" · 716 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 5.09" · 129 mm (55% of width) |
| Rim diameter | 18" |
| Circumference | 88.52" · 2.248 m |
| Revolutions per mile | 716 (445 per km) |
| Inch (flotation) equivalent | 28x9.50R18 |
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" | +3.28% | 0 mm | 62.0 mph | compare → |
| 235/50R18 common | 27.25" | -3.28% | 0 mm | 58.0 mph | compare → |
| 225/60R18 common | 28.63" | +1.61% | -10 mm | 61.0 mph | compare → |
| 225/50R18 common | 26.86" | -4.68% | -10 mm | 57.2 mph | compare → |
| 245/60R18 common | 29.57" | +4.96% | +10 mm | 63.0 mph | compare → |
| 225/55R18 common | 27.74" | -1.54% | -10 mm | 59.1 mph | compare → |
| 255/55R18 common | 29.04" | +3.07% | +20 mm | 61.8 mph | compare → |
| 245/50R18 common | 27.65" | -1.89% | +10 mm | 58.9 mph | compare → |
| 255/45R18 common | 27.04" | -4.05% | +20 mm | 57.6 mph | compare → |
| 215/55R18 common | 27.31" | -3.07% | -20 mm | 58.2 mph | compare → |
| 245/55R18 | 28.61" | +1.54% | +10 mm | 60.9 mph | compare → |
| 275/45R18 | 27.74" | -1.54% | +40 mm | 59.1 mph | compare → |
| 265/45R18 | 27.39" | -2.79% | +30 mm | 58.3 mph | compare → |
| 295/40R18 | 27.29" | -3.14% | +60 mm | 58.1 mph | compare → |
| 285/40R18 | 26.98" | -4.26% | +50 mm | 57.4 mph | calculate → |
| 345/35R18 | 27.51" | -2.38% | +110 mm | 58.6 mph | calculate → |
| 295/45R18 | 28.45" | +0.98% | +60 mm | 60.6 mph | calculate → |
| 255/50R18 | 28.04" | -0.49% | +20 mm | 59.7 mph | calculate → |
| 315/40R18 | 27.92" | -0.91% | +80 mm | 59.5 mph | calculate → |
| 155/90R18 | 28.98" | +2.86% | -80 mm | 61.7 mph | calculate → |
| 215/60R18 | 28.16" | -0.07% | -20 mm | 60.0 mph | calculate → |
| 155/85R18 | 28.37" | +0.70% | -80 mm | 60.4 mph | calculate → |
| 305/40R18 | 27.61" | -2.03% | +70 mm | 58.8 mph | calculate → |
| 305/45R18 | 28.81" | +2.24% | +70 mm | 61.3 mph | calculate → |
| 285/50R18 | 29.22" | +3.70% | +50 mm | 62.2 mph | calculate → |
| 285/45R18 | 28.10" | -0.28% | +50 mm | 59.8 mph | calculate → |
| 28x12.00R18 | 28.00" | -0.63% | +70 mm | 59.6 mph | calculate → |
| 145/85R18 | 27.70" | -1.68% | -90 mm | 59.0 mph | calculate → |
| 145/80R18 | 27.13" | -3.70% | -90 mm | 57.8 mph | calculate → |
| 165/70R18 | 27.09" | -3.84% | -70 mm | 57.7 mph | calculate → |
| 325/35R18 | 26.96" | -4.33% | +90 mm | 57.4 mph | calculate → |
| 325/45R18 | 29.52" | +4.75% | +90 mm | 62.9 mph | calculate → |
| 28x10.00R18 | 28.00" | -0.63% | +19 mm | 59.6 mph | calculate → |
| 265/50R18 | 28.43" | +0.91% | +30 mm | 60.5 mph | calculate → |
| 205/60R18 | 27.69" | -1.75% | -30 mm | 59.0 mph | calculate → |
| 195/60R18 | 27.21" | -3.42% | -40 mm | 57.9 mph | calculate → |
| 265/55R18 | 29.48" | +4.61% | +30 mm | 62.8 mph | calculate → |
| 225/65R18 | 29.52" | +4.75% | -10 mm | 62.9 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" | -0.50% | +20 mm | 59.7 mph | compare → |
| 235/60R17 common | 28.10" | -0.27% | 0 mm | 59.8 mph | compare → |
| 215/65R17 common | 28.00" | -0.61% | -20 mm | 59.6 mph | compare → |
| 235/50R19 common | 28.25" | +0.27% | 0 mm | 60.2 mph | compare → |
| 285/40R19 | 27.98" | -0.71% | +50 mm | 59.6 mph | compare → |
| 295/40R19 | 28.29" | +0.41% | +60 mm | 60.2 mph | compare → |
| 265/45R19 | 28.39" | +0.75% | +30 mm | 60.5 mph | calculate → |
| 255/55R17 | 28.04" | -0.48% | +20 mm | 59.7 mph | calculate → |
| 155/90R17 | 27.98" | -0.68% | -80 mm | 59.6 mph | calculate → |
| 28x6.00R17 | 28.00" | -0.63% | -83 mm | 59.6 mph | calculate → |
| 145/80R19 | 28.13" | -0.15% | -90 mm | 59.9 mph | calculate → |
Try another size against 235/55R18
Questions
What size is 235/55R18 in inches?
235/55R18 is about 28.2" tall and 9.3" wide on a 18-inch rim — roughly a 28x9.50R18 in inch sizing.
What does 235/55R18 mean?
235 mm section width, sidewall 55% of the width (5.09"), radial construction, 18-inch rim.
What tire sizes are equivalent to 235/55R18?
On the same 18" rim, within 3% of the diameter: 215/60R18 (-0.07%), 285/45R18 (-0.28%), 255/50R18 (-0.49%), 28x10.00R18 (-0.63%), 28x12.00R18 (-0.63%), 155/85R18 (+0.70%).
How many revolutions per mile does a 235/55R18 tire make?
About 716 revolutions per mile (circumference 88.5").
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.