235/50R18 tire size
A 235/50R18 tire is 27.3 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
- 27.25″ (692 mm)
- Section width
- 9.25″ (235 mm)
- Sidewall height
- 4.63″ (118 mm)
- Wheel diameter
- 18″
- Circumference
- 85.6″
- Revolutions per mile
- 740
What 235/50R18 means
- 235: the tire is 235 mm (9.3 in) wide from sidewall to sidewall.
- 50: the sidewall is 50% of the width, 117.5 mm (4.63 in) tall.
- R: radial construction, used by almost every modern tire.
- 18: it fits a 18-inch wheel.
Overall diameter = 18 + 2 × 4.63 = 27.25 inches.
Sizes equivalent to 235/50R18
These sizes are within 3% of the overall diameter, the usual limit for swapping without speedometer problems.
| Size | Diameter | Difference | Speedometer at 60 mph |
|---|---|---|---|
| 215/55R18 | 27.3″ | +0.2% | 60.1 mph actual |
| 235/45R19 | 27.3″ | +0.3% | 60.2 mph actual |
| 235/40R20 | 27.4″ | +0.5% | 60.3 mph actual |
| 225/40R20 | 27.1″ | -0.6% | 59.6 mph actual |
| 215/50R19 | 27.5″ | +0.8% | 60.5 mph actual |
| 255/45R18 | 27.0″ | -0.8% | 59.5 mph actual |
| 255/40R19 | 27.0″ | -0.8% | 59.5 mph actual |
| 255/35R20 | 27.0″ | -0.8% | 59.5 mph actual |
| 225/45R19 | 27.0″ | -1.0% | 59.4 mph actual |
| 215/45R20 | 27.6″ | +1.3% | 60.8 mph actual |
Going a size taller? 225/55R18 is 27.7″ tall, 1.8% more than 235/50R18. Compare any two sizes in the tire size calculator.
See every common size side by side in the tire size chart.
Questions
What is 235/50R18 in inches?
A 235/50R18 tire is about 27.3 inches tall (692 mm) and 9.3 inches wide, on a 18-inch wheel. In flotation sizing that's roughly 27.3x9.3R18.
How tall is a 235/50R18 tire?
The overall diameter is 27.25 inches: the 18-inch wheel plus two 4.63-inch sidewalls. Actual tires vary by a few tenths of an inch between brands and models.
How many revolutions per mile does a 235/50R18 make?
About 740 revolutions per mile, from a circumference of 85.6 inches.
