315/40R18 tires are 27.9″ tall, have a section width of 12.4″, and fit wheels with a diameter of 18. The circumference is 87.7″ that translates into 723 revolutions per mile. As a rule, they can be mounted on the wheels with 18″ x 10.5-12.5″ rim width. In the high flotation system, the equivalent tire size is 27.9×12.4R18.
What is 315/40R18 in inches?
| Tire Diameter: | 27.9″ |
| Tire Section Width: | 12.4″ |
| Rim Width Range: | 18″ x 10.5-12.5″ |
| Sidewall Height: | 5.0″ |
| Circumference: | 87.7″ |
| Revs/Mile: | 723 |
Alternate sizes – Upsizing Wheels or Tires?
What is a 315/40R18 equivalent to?
Check out the chart below to find possible alternatives to the 315/40R18 tire size staying within the 3%-range of the tire diameter, allowing to choose wider wheels or tires with smaller sidewalls. A good rule of thumb is to avoid decreasing the diameter of the wheel. If you are not sure about the custom sizes, consult the experts or stick to the factory tire size.
| Tire size | Diameter | Difference | Width | Wheel size |
|---|---|---|---|---|
| 215/55R18 | 27.3″ | -2.15% | 8.5″ | 18 |
| 225/55R18 | 27.7″ | -0.72% | 8.9″ | 18 |
| 235/50R18 | 27.3″ | -2.15% | 9.3″ | 18 |
| 245/50R18 | 27.6″ | -1.08% | 9.6″ | 18 |
| 265/45R18 | 27.4″ | -1.79% | 10.4″ | 18 |
| 275/45R18 | 27.7″ | -0.72% | 10.8″ | 18 |
| 295/40R18 | 27.3″ | -2.15% | 11.6″ | 18 |
| 305/40R18 | 27.6″ | -1.08% | 12.0″ | 18 |
| 345/35R18 | 27.5″ | -1.43% | 13.6″ | 18 |
| 155/85R18 | 28.4″ | 1.79% | 6.1″ | 18 |
| 225/60R18 | 28.6″ | 2.51% | 8.9″ | 18 |
| 235/55R18 | 28.2″ | 1.08% | 9.3″ | 18 |
| 245/55R18 | 28.6″ | 2.51% | 9.6″ | 18 |
| 255/50R18 | 28.0″ | 0.36% | 10.0″ | 18 |
| 305/42/R18 | 28.0″ | 0.36% | 12.0″ | 18 |
| 295/45R18 | 28.5″ | 2.15% | 11.6″ | 18 |
What does 315/40R18 mean?
Trying to decode the size of the tires? Scroll down the page to learn what all these numbers on the sidewall stand for.
| P or LT | The first letter in the string denotes the class. P stands for passenger vehicles, LT is intended for light trucks carrying heavy loads. |
| 315 | It means the width of the tire is 315 millimeters |
| 40 | The tire has an aspect ratio of 40. To put it simple, the sidewall height is 40% of the width, so it would be 5.0″. |
| R | R stands for the Radial, a standard construction method for about 99% of tires. |
| 18 | The tire is designed to fit 18″ x 10.5-12.5″ rims that are 18 inches in diameter. |
Popular questions about 315/40R18 tire size
How wide is a 315/40R18 tire?
The tires of the given size have a section width of 12.4″ inches.
How tall is a 315/40R18 tire?
The height of the following tire size equals 27.9″ inches.
What rims will fit 315/40R18 tires?
For each tire size, often there are several wheel sizes. You can’t put very wide tires on narrow rims or vise versa. You need the rim size of 18″ x 10.5-12.5″ for 315/40R18 tires.
