189Best 205/40 R18 tires
16 rated tires available in this size, scored on dry, wet, snow, comfort and wear. Top overall right now is the Michelin Pilot Sport 4 at 89/100.
24.5″
overall diameter
8.1″
section width
18″
rim diameter
824.6
revs per mile
Best 205/40 R18 summer tires
10189
283
379
477
839
970
1066Best 205/40 R18 winter tires
2
180
More top-rated 205/40 R18 tires
2
184
283Best 205/40 R18 all-season tires
2
184
272Conversion
205/40 R18 in inches
| Overall diameter | 24.5″ |
| Section width | 8.1″ |
| Rim diameter | 18″ |
| Sidewall height | 82 mm |
| Circumference | 76.8″ |
| Revolutions per mile | 824.6 |
The closest flotation size is 28x12.00R18 — 14.5% taller and 48.7% wider. Compare them in the calculator.
Wheels
What rims fit 205/40 R18 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
5.5″
Ideal
6.5″
Maximum
7.5″
Rim diameter is fixed at 18″ — only the width varies. Estimated from the 8.1″ section width (70–90% rule).
Fitted from the factory on rims: 18x7, 18x7.5, 18x8.
Popular comparisons
Sizes often compared with 205/40 R18
Close alternatives — each opens in the tire size calculator.
Sidewall
205/40 R18 — what does it mean?
| Parameter | Meaning |
|---|---|
| 205 | The first number is the section width — 205 mm, or about 8.1 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 82 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. |