Best 345/30 R21 tires
We don't have rated tires listed in this size yet — the conversion, rim fitment and comparisons below still apply.
29.1″
overall diameter
13.6″
section width
21″
rim diameter
691.9
revs per mile
Conversion
345/30 R21 in inches
| Overall diameter | 29.1″ |
| Section width | 13.6″ |
| Rim diameter | 21″ |
| Sidewall height | 104 mm |
| Circumference | 91.6″ |
| Revolutions per mile | 691.9 |
Wheels
What rims fit 345/30 R21 tires?
A tire fits a range of rim widths. Too narrow or too wide and the sidewall changes shape.
Minimum
9.5″
Ideal
11″
Maximum
12″
Rim diameter is fixed at 21″ — only the width varies. Estimated from the 13.6″ section width (70–90% rule).
Fitted from the factory on rims: 21x12, 21x12.5.
Sidewall
345/30 R21 — what does it mean?
| Parameter | Meaning |
|---|---|
| 345 | The first number is the section width — 345 mm, or about 13.6 inches across the widest part of the tire. |
| 30 | The second number is the aspect ratio: sidewall height as a percentage of width. At 30%, the sidewall is about 104 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. |