Best 315/40 R20 tires
We don't have rated tires listed in this size yet — the conversion, rim fitment and comparisons below still apply.
29.9″
overall diameter
12.4″
section width
20″
rim diameter
674
revs per mile
Conversion
315/40 R20 in inches
| Overall diameter | 29.9″ |
| Section width | 12.4″ |
| Rim diameter | 20″ |
| Sidewall height | 126 mm |
| Circumference | 94″ |
| Revolutions per mile | 674 |
The closest flotation size is 33x12.50R20 — 10.3% taller and 0.8% wider. Compare them in the calculator.
Wheels
What rims fit 315/40 R20 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 20″ — only the width varies. Estimated from the 12.4″ section width (70–90% rule).
Fitted from the factory on rims: 20x11.
Sidewall
315/40 R20 — 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. |
| R20 | R means radial construction, which nearly all modern tires use. The number is the rim diameter in inches — this tire fits a 20-inch wheel. |