235/65R18 tire size
A 235/65R18 tire is 30.0 inches tall and 9.3 inches wide. Here are its full dimensions, what the numbers mean, and the sizes you can swap it for.
- Overall diameter
- 30.03″ (763 mm)
- Section width
- 9.25″ (235 mm)
- Sidewall height
- 6.01″ (153 mm)
- Wheel diameter
- 18″
- Circumference
- 94.3″
- Revolutions per mile
- 672
What 235/65R18 means
- 235: the tire is 235 mm (9.3 in) wide from sidewall to sidewall.
- 65: the sidewall is 65% of the width, 152.8 mm (6.01 in) tall.
- R: radial construction, used by almost every modern tire.
- 18: it fits a 18-inch wheel.
Overall diameter = 18 + 2 × 6.01 = 30.03 inches.
Sizes equivalent to 235/65R18
These sizes are within 3% of the overall diameter, the usual limit for swapping without speedometer problems.
| Size | Diameter | Difference | Speedometer at 60 mph |
|---|---|---|---|
| 255/50R20 | 30.0″ | +0.0% | 60.0 mph actual |
| 255/55R19 | 30.0″ | +0.1% | 60.0 mph actual |
| 255/60R18 | 30.0″ | +0.1% | 60.0 mph actual |
| 215/65R19 | 30.0″ | -0.1% | 60.0 mph actual |
| 235/60R19 | 30.1″ | +0.2% | 60.1 mph actual |
| 215/60R20 | 30.2″ | +0.4% | 60.3 mph actual |
| 235/55R20 | 30.2″ | +0.5% | 60.3 mph actual |
| 215/70R18 | 29.9″ | -0.6% | 59.6 mph actual |
| 225/55R20 | 29.7″ | -0.9% | 59.4 mph actual |
| 225/70R18 | 30.4″ | +1.2% | 60.7 mph actual |
Going a size taller? 255/60R18 is 30.0″ tall, 0.1% more than 235/65R18. Compare any two sizes in the tire size calculator.
See every common size side by side in the tire size chart.
Questions
What is 235/65R18 in inches?
A 235/65R18 tire is about 30.0 inches tall (763 mm) and 9.3 inches wide, on a 18-inch wheel. In flotation sizing that's roughly 30.0x9.3R18.
How tall is a 235/65R18 tire?
The overall diameter is 30.03 inches: the 18-inch wheel plus two 6.01-inch sidewalls. Actual tires vary by a few tenths of an inch between brands and models.
How many revolutions per mile does a 235/65R18 make?
About 672 revolutions per mile, from a circumference of 94.3 inches.
