235/45R18 tire size
235/45R18 is a metric size: 26.3" tall, 9.3" wide, on a 18" rim — about a 26.5x9.50R18. The sidewall is 4.2" and the tire turns 766 times per mile.
235/45R18 specs
| Overall diameter (height) | 26.33" · 669 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 4.16" · 106 mm (45% of width) |
| Rim diameter | 18" |
| Circumference | 82.71" · 2.101 m |
| Revolutions per mile | 766 (476 per km) |
| Inch (flotation) equivalent | 26.5x9.50R18 |
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 | |
|---|---|---|---|---|---|
| 225/45R18 common | 25.97" | -1.35% | -10 mm | 59.2 mph | compare → |
| 245/40R18 common | 25.72" | -2.32% | +10 mm | 58.6 mph | compare → |
| 225/40R18 common | 25.09" | -4.71% | -10 mm | 57.2 mph | compare → |
| 245/45R18 common | 26.68" | +1.35% | +10 mm | 60.8 mph | compare → |
| 235/50R18 common | 27.25" | +3.51% | 0 mm | 62.1 mph | compare → |
| 235/40R18 common | 25.40" | -3.51% | 0 mm | 57.9 mph | compare → |
| 225/50R18 common | 26.86" | +2.02% | -10 mm | 61.2 mph | compare → |
| 255/35R18 common | 25.03" | -4.93% | +20 mm | 57.0 mph | compare → |
| 255/40R18 common | 26.03" | -1.12% | +20 mm | 59.3 mph | compare → |
| 275/35R18 common | 25.58" | -2.84% | +40 mm | 58.3 mph | compare → |
| 265/35R18 common | 25.30" | -3.89% | +30 mm | 57.7 mph | compare → |
| 255/45R18 common | 27.04" | +2.69% | +20 mm | 61.6 mph | compare → |
| 215/55R18 common | 27.31" | +3.74% | -20 mm | 62.2 mph | compare → |
| 275/40R18 common | 26.66" | +1.27% | +40 mm | 60.8 mph | compare → |
| 215/45R18 common | 25.62" | -2.69% | -20 mm | 58.4 mph | compare → |
| 265/40R18 | 26.35" | +0.07% | +30 mm | 60.0 mph | compare → |
| 285/35R18 | 25.85" | -1.79% | +50 mm | 58.9 mph | compare → |
| 315/30R18 | 25.44" | -3.36% | +80 mm | 58.0 mph | compare → |
| 295/35R18 | 26.13" | -0.75% | +60 mm | 59.6 mph | compare → |
| 335/30R18 | 25.91" | -1.57% | +100 mm | 59.1 mph | compare → |
| 215/50R18 | 26.46" | +0.52% | -20 mm | 60.3 mph | compare → |
| 295/40R18 | 27.29" | +3.66% | +60 mm | 62.2 mph | compare → |
| 265/45R18 | 27.39" | +4.04% | +30 mm | 62.4 mph | compare → |
| 285/40R18 | 26.98" | +2.47% | +50 mm | 61.5 mph | calculate → |
| 305/35R18 | 26.41" | +0.30% | +70 mm | 60.2 mph | calculate → |
| 345/35R18 | 27.51" | +4.49% | +110 mm | 62.7 mph | calculate → |
| 305/40R18 | 27.61" | +4.86% | +70 mm | 62.9 mph | calculate → |
| 155/70R18 | 26.54" | +0.82% | -80 mm | 60.5 mph | calculate → |
| 26x12.00R18 | 26.00" | -1.24% | +70 mm | 59.3 mph | calculate → |
| 26x6.00R18 | 26.00" | -1.24% | -83 mm | 59.3 mph | calculate → |
| 26x8.00R18 | 26.00" | -1.24% | -32 mm | 59.3 mph | calculate → |
| 145/70R18 | 25.99" | -1.27% | -90 mm | 59.2 mph | calculate → |
| 325/35R18 | 26.96" | +2.39% | +90 mm | 61.4 mph | calculate → |
| 165/70R18 | 27.09" | +2.92% | -70 mm | 61.7 mph | calculate → |
| 145/80R18 | 27.13" | +3.07% | -90 mm | 61.8 mph | calculate → |
| 155/60R18 | 25.32" | -3.81% | -80 mm | 57.7 mph | calculate → |
| 305/30R18 | 25.20" | -4.26% | +70 mm | 57.4 mph | calculate → |
| 345/30R18 | 26.15" | -0.67% | +110 mm | 59.6 mph | calculate → |
| 315/35R18 | 26.68" | +1.35% | +80 mm | 60.8 mph | calculate → |
| 195/60R18 | 27.21" | +3.36% | -40 mm | 62.0 mph | calculate → |
| 205/45R18 | 25.26" | -4.04% | -30 mm | 57.6 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 | |
|---|---|---|---|---|---|
| 215/55R17 common | 26.31" | -0.06% | -20 mm | 60.0 mph | compare → |
| 235/40R19 common | 26.40" | +0.28% | 0 mm | 60.2 mph | compare → |
| 275/35R19 common | 26.58" | +0.96% | +40 mm | 60.6 mph | compare → |
| 225/40R19 common | 26.09" | -0.91% | -10 mm | 59.5 mph | compare → |
| 235/50R17 common | 26.25" | -0.28% | 0 mm | 59.8 mph | compare → |
| 265/35R19 common | 26.30" | -0.09% | +30 mm | 59.9 mph | compare → |
| 305/30R19 | 26.20" | -0.46% | +70 mm | 59.7 mph | compare → |
| 315/30R19 | 26.44" | +0.43% | +80 mm | 60.3 mph | compare → |
| 335/35R17 | 26.23" | -0.36% | +100 mm | 59.8 mph | calculate → |
| 195/60R17 | 26.21" | -0.43% | -40 mm | 59.7 mph | calculate → |
| 145/80R17 | 26.13" | -0.73% | -90 mm | 59.6 mph | calculate → |
| 295/40R17 | 26.29" | -0.13% | +60 mm | 59.9 mph | calculate → |
| 165/70R17 | 26.09" | -0.88% | -70 mm | 59.5 mph | calculate → |
Try another size against 235/45R18
Questions
What size is 235/45R18 in inches?
235/45R18 is about 26.3" tall and 9.3" wide on a 18-inch rim — roughly a 26.5x9.50R18 in inch sizing.
What does 235/45R18 mean?
235 mm section width, sidewall 45% of the width (4.16"), radial construction, 18-inch rim.
What tire sizes are equivalent to 235/45R18?
On the same 18" rim, within 3% of the diameter: 265/40R18 (+0.07%), 305/35R18 (+0.30%), 215/50R18 (+0.52%), 345/30R18 (-0.67%), 295/35R18 (-0.75%), 155/70R18 (+0.82%).
How many revolutions per mile does a 235/45R18 tire make?
About 766 revolutions per mile (circumference 82.7").
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.