192Best 315/40 R18 tires
2 rated tires available in this size, scored on dry, wet, snow, comfort and wear. Top overall right now is the Hoosier R7 at 92/100.
27.9″
overall diameter
12.4″
section width
18″
rim diameter
722.3
revs per mile
More top-rated 315/40 R18 tires
1192Best 315/40 R18 summer tires
1
184Conversion
315/40 R18 in inches
| Overall diameter | 27.9″ |
| Section width | 12.4″ |
| Rim diameter | 18″ |
| Sidewall height | 126 mm |
| Circumference | 87.7″ |
| Revolutions per mile | 722.3 |
The closest flotation size is 28x12.00R18 — 0.3% taller and 3.2% narrower. Compare them in the calculator.
Wheels
What rims fit 315/40 R18 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
8.5″
Ideal
10″
Maximum
11″
Rim diameter is fixed at 18″ — only the width varies. Estimated from the 12.4″ section width (70–90% rule).
Fitted from the factory on rims: 18x11.
Sidewall
315/40 R18 — what does it mean?
| Parameter | Meaning |
|---|---|
| 315 | The first number is the section width — 315 mm, or about 12.4 inches across the widest part of the tire. |
| 40 | The second number is the aspect ratio: sidewall height as a percentage of width. At 40%, the sidewall is about 126 mm tall. |
| R18 | R means radial construction, which nearly all modern tires use. The number is the rim diameter in inches — this tire fits a 18-inch wheel. |