255/65R18 tire size
A 255/65R18 tire is 31.1 inches tall and 10.0 inches wide. Here are its full dimensions, what the numbers mean, and the sizes you can swap it for.
- Overall diameter
- 31.05″ (789 mm)
- Section width
- 10.04″ (255 mm)
- Sidewall height
- 6.53″ (166 mm)
- Wheel diameter
- 18″
- Circumference
- 97.6″
- Revolutions per mile
- 650
What 255/65R18 means
- 255: the tire is 255 mm (10.0 in) wide from sidewall to sidewall.
- 65: the sidewall is 65% of the width, 165.8 mm (6.53 in) tall.
- R: radial construction, used by almost every modern tire.
- 18: it fits a 18-inch wheel.
Overall diameter = 18 + 2 × 6.53 = 31.05 inches.
Sizes equivalent to 255/65R18
These sizes are within 3% of the overall diameter, the usual limit for swapping without speedometer problems.
| Size | Diameter | Difference | Speedometer at 60 mph |
|---|---|---|---|
| 255/60R19 | 31.0″ | -0.0% | 60.0 mph actual |
| 255/55R20 | 31.0″ | -0.0% | 60.0 mph actual |
| 235/65R19 | 31.0″ | -0.1% | 60.0 mph actual |
| 235/60R20 | 31.1″ | +0.2% | 60.1 mph actual |
| 275/60R18 | 31.0″ | -0.2% | 59.9 mph actual |
| 235/70R18 | 31.0″ | -0.3% | 59.8 mph actual |
| 275/55R19 | 30.9″ | -0.5% | 59.7 mph actual |
| 275/50R20 | 30.8″ | -0.7% | 59.6 mph actual |
| 265/55R20 | 31.5″ | +1.4% | 60.8 mph actual |
| 245/55R20 | 30.6″ | -1.4% | 59.1 mph actual |
Going a size taller? 265/65R18 is 31.6″ tall, 1.6% more than 255/65R18. Compare any two sizes in the tire size calculator.
See every common size side by side in the tire size chart.
Questions
What is 255/65R18 in inches?
A 255/65R18 tire is about 31.1 inches tall (789 mm) and 10.0 inches wide, on a 18-inch wheel. In flotation sizing that's roughly 31.1x10.0R18.
How tall is a 255/65R18 tire?
The overall diameter is 31.05 inches: the 18-inch wheel plus two 6.53-inch sidewalls. Actual tires vary by a few tenths of an inch between brands and models.
Can I put 265/65R18 instead of 255/65R18?
265/65R18 is 0.51 inches taller (1.6%) and 10 mm wider. That's within the usual 3% limit, but check that your wheel width is approved for it and that it clears the suspension.
How many revolutions per mile does a 255/65R18 make?
About 650 revolutions per mile, from a circumference of 97.6 inches.
