184Best 305/40 R20 tires
12 rated tires available in this size, scored on dry, wet, snow, comfort and wear. Top overall right now is the Michelin Pilot Sport 4 SUV at 84/100.
29.6″
overall diameter
12″
section width
20″
rim diameter
681.2
revs per mile
Best 305/40 R20 summer tires
7184
279
377
573
670
767Best 305/40 R20 winter tires
3
182
281
378Best 305/40 R20 all-season tires
1
174More top-rated 305/40 R20 tires
1
158Conversion
305/40 R20 in inches
| Overall diameter | 29.6″ |
| Section width | 12″ |
| Rim diameter | 20″ |
| Sidewall height | 122 mm |
| Circumference | 93″ |
| Revolutions per mile | 681.2 |
The closest flotation size is 33x12.00R20 — 11.5% taller and 0.1% narrower. Compare them in the calculator.
Wheels
What rims fit 305/40 R20 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
8.5″
Ideal
9.5″
Maximum
11″
Rim diameter is fixed at 20″ — only the width varies. Estimated from the 12″ section width (70–90% rule).
Fitted from the factory on rims: 20x10.5.
Popular comparisons
Sizes often compared with 305/40 R20
Close alternatives — each opens in the tire size calculator.
Sidewall
305/40 R20 — what does it mean?
| Parameter | Meaning |
|---|---|
| 305 | The first number is the section width — 305 mm, or about 12 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 122 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. |