184Best 285/40 R21 tires
31 rated tires available in this size, scored on dry, wet, snow, comfort and wear. Top overall right now is the Michelin Pilot Sport All Season 4 at 88/100.
30″
overall diameter
11.2″
section width
21″
rim diameter
672.8
revs per mile
Best 285/40 R21 summer tires
14184
282
383
487
581
681
776
975
1074
1173
12702 more rated tires in this size are listed on their brand pages.
Best 285/40 R21 all-season tires
9
188
286
384
477
774
862
963More top-rated 285/40 R21 tires
7
188
293
386
488
577
688
758Best 285/40 R21 winter tires
1
181Conversion
285/40 R21 in inches
| Overall diameter | 30″ |
| Section width | 11.2″ |
| Rim diameter | 21″ |
| Sidewall height | 114 mm |
| Circumference | 94.2″ |
| Revolutions per mile | 672.8 |
Wheels
What rims fit 285/40 R21 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
8″
Ideal
9″
Maximum
10″
Rim diameter is fixed at 21″ — only the width varies. Estimated from the 11.2″ section width (70–90% rule).
Fitted from the factory on rims: 21x9.5, 21x10, 21x10.5, 21x11.
Popular comparisons
Sizes often compared with 285/40 R21
Close alternatives — each opens in the tire size calculator.
Sidewall
285/40 R21 — what does it mean?
| Parameter | Meaning |
|---|---|
| 285 | The first number is the section width — 285 mm, or about 11.2 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 114 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. |