315/55R18 tire size
315/55R18 in inches: 31.64" overall diameter — 12.40" wide, 6.82" sidewall.
Overall diameter 31.64 in 803.7 mm
Section width 12.40 in 315 mm
Sidewall height 6.82 in 173.25 mm
Revs / mile 637 speedo calibration
Full dimensions
| Measurement | Metric | Imperial |
|---|---|---|
| Overall diameter | 803.7 mm | 31.64 in |
| Section width | 315 mm | 12.40 in |
| Sidewall height | 173.25 mm | 6.82 in |
| Rim diameter | 457.2 mm | 18 in |
| Circumference | 2524.9 mm | 99.41 in |
| Revolutions per mile | 637.4 | |
| Aspect ratio | 55% | |
Compare 315/55R18 to similar sizes
Frequently asked questions
What is the overall diameter of a 315/55R18 tire?
A 315/55R18 tire has an overall diameter of 31.64 inches (803.7 mm).
How tall is a 315/55R18 tire?
The sidewall height is 173.25 mm (6.82 inches), and the overall diameter from the ground to the top of the tire is 31.64 inches.
How many revolutions per mile does a 315/55R18 tire make?
A 315/55R18 tire makes approximately 637 revolutions per mile. Your speedometer is calibrated to this number.
What rim size does a 315/55R18 tire fit?
A 315/55R18 tire is designed for a 18-inch rim (457.2 mm).
All dimensions calculated using standard ETRTO formulas. Always confirm fitment with your vehicle's door-placard and a qualified tire professional before purchasing.