Best 165/40R18 tires
3 rated tires available in this size, scored on dry, wet, snow, comfort and wear.
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Every rated 165/40R18 tire, by season
Ranked by our Relative score, weighed against how many reviews and tests stand behind it.
How scores work
- Relative score
- 0–100. Blends road tests (60%) and owner reviews (40%) category by category, the same way on every TireWheelGuide page. With only one of the two, the missing half is estimated from it, so the score stays closer to average. It needs at least one road test or five owner reviews.
- Ranking
- The score already allows for how much stands behind it: with only a few reviews or tests a tire stays near the typical score. Among similar scores, newer tires rank higher and tires replaced by a newer generation lower.
Best 165/40R18 summer tires
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165/40R18 in inches
| Overall diameter | 23.2″ |
| Section width | 6.5″ |
| Rim diameter | 18″ |
| Sidewall height | 66 mm |
| Circumference | 72.9″ |
| Revolutions per mile | 869.4 |
Revolutions per mile: how many times the tire turns in one mile, the count your speedometer is calibrated to.
What rims fit 165/40R18 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
4.5″
Ideal
5″
Maximum
6″
The rim diameter is fixed at 18″; only the width can change. Rims are usually 70–90% as wide as the tire’s 6.5″ section width.
165/40R18 — what does it mean?
| Parameter | Meaning |
|---|---|
| 165 | The first number is the section width — 165 mm, or about 6.5 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 66 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. |