235/80R18 tire size
235/80R18 is a metric size: 32.8" tall, 9.3" wide, on a 18" rim — about a 33x9.50R18. The sidewall is 7.4" and the tire turns 615 times per mile.
235/80R18 specs
| Overall diameter (height) | 32.80" · 833 mm |
|---|---|
| Section width | 9.25" · 235 mm |
| Sidewall height | 7.40" · 188 mm (80% of width) |
| Rim diameter | 18" |
| Circumference | 103.05" · 2.618 m |
| Revolutions per mile | 615 (382 per km) |
| Inch (flotation) equivalent | 33x9.50R18 |
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 | |
|---|---|---|---|---|---|
| 275/65R18 common | 32.07" | -2.22% | +40 mm | 58.7 mph | calculate → |
| 275/70R18 common | 33.16" | +1.08% | +40 mm | 60.6 mph | calculate → |
| 265/65R18 common | 31.56" | -3.78% | +30 mm | 57.7 mph | calculate → |
| 265/70R18 common | 32.61" | -0.60% | +30 mm | 59.6 mph | calculate → |
| 255/70R18 common | 32.06" | -2.28% | +20 mm | 58.6 mph | calculate → |
| 285/65R18 common | 32.59" | -0.66% | +50 mm | 59.6 mph | calculate → |
| 295/70R18 common | 34.26" | +4.44% | +60 mm | 62.7 mph | calculate → |
| 33x12.50R18 | 33.00" | +0.60% | +83 mm | 60.4 mph | calculate → |
| 285/60R18 | 31.46" | -4.08% | +50 mm | 57.6 mph | calculate → |
| 305/65R18 | 33.61" | +2.46% | +70 mm | 61.5 mph | calculate → |
| 305/60R18 | 32.41" | -1.20% | +70 mm | 59.3 mph | calculate → |
| 285/70R18 | 33.71" | +2.76% | +50 mm | 61.7 mph | calculate → |
| 325/60R18 | 33.35" | +1.68% | +90 mm | 61.0 mph | calculate → |
| 245/75R18 | 32.47" | -1.02% | +10 mm | 59.4 mph | calculate → |
| 295/65R18 | 33.10" | +0.90% | +60 mm | 60.5 mph | calculate → |
| 245/70R18 | 31.50" | -3.96% | +10 mm | 57.6 mph | calculate → |
| 33x11.50R18 | 33.00" | +0.60% | +57 mm | 60.4 mph | calculate → |
| 33x13.50R18 | 33.00" | +0.60% | +108 mm | 60.4 mph | calculate → |
| 33x13.00R18 | 33.00" | +0.60% | +95 mm | 60.4 mph | calculate → |
| 34x12.50R18 | 34.00" | +3.65% | +83 mm | 62.2 mph | calculate → |
| 33x10.50R18 | 33.00" | +0.60% | +32 mm | 60.4 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 | |
|---|---|---|---|---|---|
| 285/70R17 common | 32.71" | -0.29% | +50 mm | 59.8 mph | calculate → |
| 33x12.50R17 | 33.00" | +0.60% | +83 mm | 60.4 mph | calculate → |
| 255/80R17 | 33.06" | +0.79% | +20 mm | 60.5 mph | calculate → |
| 305/65R17 | 32.61" | -0.59% | +70 mm | 59.6 mph | calculate → |
| 33x10.50R17 | 33.00" | +0.60% | +32 mm | 60.4 mph | calculate → |
| 33x11.50R17 | 33.00" | +0.60% | +57 mm | 60.4 mph | calculate → |
| 33x13.50R17 | 33.00" | +0.60% | +108 mm | 60.4 mph | calculate → |
| 33x13.00R17 | 33.00" | +0.60% | +95 mm | 60.4 mph | calculate → |
| 33x9.50R17 | 33.00" | +0.60% | +6 mm | 60.4 mph | calculate → |
| 235/85R17 | 32.73" | -0.23% | 0 mm | 59.9 mph | calculate → |
Try another size against 235/80R18
Questions
What size is 235/80R18 in inches?
235/80R18 is about 32.8" tall and 9.3" wide on a 18-inch rim — roughly a 33x9.50R18 in inch sizing.
What does 235/80R18 mean?
235 mm section width, sidewall 80% of the width (7.40"), radial construction, 18-inch rim.
What tire sizes are equivalent to 235/80R18?
On the same 18" rim, within 3% of the diameter: 265/70R18 (-0.60%), 33x10.50R18 (+0.60%), 33x11.50R18 (+0.60%), 33x12.50R18 (+0.60%), 33x13.50R18 (+0.60%), 33x13.00R18 (+0.60%).
How many revolutions per mile does a 235/80R18 tire make?
About 615 revolutions per mile (circumference 103.1").
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.