177Best 245/40 R21 tires
18 rated tires available in this size, scored on dry, wet, snow, comfort and wear. Top overall right now is the Falken Azenis FK460 A/S at 88/100.
28.7″
overall diameter
9.6″
section width
21″
rim diameter
702.3
revs per mile
Best 245/40 R21 summer tires
10177
276
574
672
768
870
967
1053More top-rated 245/40 R21 tires
4
188
283
386
480Best 245/40 R21 winter tires
2
181
Best 245/40 R21 all-season tires
2
177
Conversion
245/40 R21 in inches
| Overall diameter | 28.7″ |
| Section width | 9.6″ |
| Rim diameter | 21″ |
| Sidewall height | 98 mm |
| Circumference | 90.2″ |
| Revolutions per mile | 702.3 |
Wheels
What rims fit 245/40 R21 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
7″
Ideal
7.5″
Maximum
8.5″
Rim diameter is fixed at 21″ — only the width varies. Estimated from the 9.6″ section width (70–90% rule).
Fitted from the factory on rims: 21x8, 21x8.5, 21x9, 21x9.5, 21x10.5.
Popular comparisons
Sizes often compared with 245/40 R21
Close alternatives — each opens in the tire size calculator.
Sidewall
245/40 R21 — what does it mean?
| Parameter | Meaning |
|---|---|
| 245 | The first number is the section width — 245 mm, or about 9.6 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 98 mm tall. |
| R21 | R means radial construction, which nearly all modern tires use. The number is the rim diameter in inches — this tire fits a 21-inch wheel. |