21-inch tire sizes
26 common 21-inch sizes, from 275/30R21 at 27.50 in to 275/50R21 at 31.83 in overall diameter, sorted shortest to tallest below.
The median 21-inch size in this list by overall diameter is 235/45R21 at 29.33 in, turning 688 times per mile.
Section widths run from 235 mm to 325 mm, and the most frequent aspect ratio here is 35% (7 sizes).
| Size | Diameter | Width | Sidewall | Rev/mile |
|---|---|---|---|---|
| 275/30R21 | 27.50 in | 10.83 in | 3.25 in | 733 |
| 245/35R21 | 27.75 in | 9.65 in | 3.38 in | 727 |
| 295/30R21 | 27.97 in | 11.61 in | 3.48 in | 721 |
| 255/35R21 | 28.03 in | 10.04 in | 3.51 in | 720 |
| 305/30R21 | 28.20 in | 12.01 in | 3.60 in | 715 |
| 265/35R21 | 28.30 in | 10.43 in | 3.65 in | 713 |
| 275/35R21 | 28.58 in | 10.83 in | 3.79 in | 706 |
| 325/30R21 | 28.68 in | 12.80 in | 3.84 in | 703 |
| 245/40R21 | 28.72 in | 9.65 in | 3.86 in | 702 |
| 285/35R21 | 28.85 in | 11.22 in | 3.93 in | 699 |
| 255/40R21 | 29.03 in | 10.04 in | 4.02 in | 695 |
| 295/35R21 | 29.13 in | 11.61 in | 4.06 in | 692 |
| 235/45R21 | 29.33 in | 9.25 in | 4.16 in | 688 |
| 265/40R21 | 29.35 in | 10.43 in | 4.17 in | 687 |
| 275/40R21 | 29.66 in | 10.83 in | 4.33 in | 680 |
| 245/45R21 | 29.68 in | 9.65 in | 4.34 in | 679 |
| 315/35R21 | 29.68 in | 12.40 in | 4.34 in | 679 |
| 285/40R21 | 29.98 in | 11.22 in | 4.49 in | 673 |
| 255/45R21 | 30.04 in | 10.04 in | 4.52 in | 671 |
| 295/40R21 | 30.29 in | 11.61 in | 4.65 in | 666 |
| 265/45R21 | 30.39 in | 10.43 in | 4.69 in | 664 |
| 275/45R21 | 30.74 in | 10.83 in | 4.87 in | 656 |
| 255/50R21 | 31.04 in | 10.04 in | 5.02 in | 650 |
| 285/45R21 | 31.10 in | 11.22 in | 5.05 in | 649 |
| 265/50R21 | 31.43 in | 10.43 in | 5.22 in | 642 |
| 275/50R21 | 31.83 in | 10.83 in | 5.41 in | 634 |
Common 21-inch comparisons
- 275/30R21 vs 295/30R21 (+1.72%)
- 275/30R21 vs 275/35R21 (+3.94%)
- 245/35R21 vs 255/35R21 (+0.99%)
- 245/35R21 vs 265/35R21 (+1.99%)
- 245/35R21 vs 245/40R21 (+3.48%)
- 295/30R21 vs 305/30R21 (+0.84%)
- 295/30R21 vs 295/35R21 (+4.15%)
- 255/35R21 vs 265/35R21 (+0.98%)
- 255/35R21 vs 275/35R21 (+1.97%)
- 255/35R21 vs 255/40R21 (+3.58%)
- 305/30R21 vs 325/30R21 (+1.68%)
- 265/35R21 vs 275/35R21 (+0.97%)
- 265/35R21 vs 285/35R21 (+1.95%)
- 265/35R21 vs 265/40R21 (+3.69%)
- 275/35R21 vs 285/35R21 (+0.96%)
- 275/35R21 vs 295/35R21 (+1.93%)
- 275/35R21 vs 275/40R21 (+3.79%)
- 245/40R21 vs 255/40R21 (+1.10%)
- 245/40R21 vs 265/40R21 (+2.19%)
- 245/40R21 vs 245/45R21 (+3.36%)
- 285/35R21 vs 295/35R21 (+0.96%)
- 285/35R21 vs 285/40R21 (+3.89%)
- 255/40R21 vs 265/40R21 (+1.08%)
- 255/40R21 vs 275/40R21 (+2.17%)
- 255/40R21 vs 255/45R21 (+3.46%)
- 295/35R21 vs 315/35R21 (+1.89%)
- 295/35R21 vs 295/40R21 (+3.99%)
- 235/45R21 vs 245/45R21 (+1.21%)
- 235/45R21 vs 255/45R21 (+2.42%)
- 265/40R21 vs 275/40R21 (+1.07%)
Plus-size options from 21-inch
- 255/45R21 vs 255/40R22 (−0.01%)
- 255/40R21 vs 255/35R22 (−0.01%)
- 255/35R21 vs 255/30R22 (−0.01%)
- 265/45R21 vs 305/35R22 (+0.05%)
- 245/40R21 vs 285/30R22 (+0.05%)
- 235/45R21 vs 265/35R22 (−0.08%)
- 245/40R21 vs 245/35R22 (+0.12%)
- 245/35R21 vs 245/30R22 (+0.13%)
- 265/50R21 vs 265/45R22 (−0.14%)
- 265/45R21 vs 265/40R22 (−0.14%)
- 265/40R21 vs 265/35R22 (−0.15%)
- 265/35R21 vs 265/30R22 (−0.15%)
- 295/40R21 vs 265/40R22 (+0.18%)
- 285/40R21 vs 255/40R22 (+0.18%)
- 325/30R21 vs 285/30R22 (+0.19%)
- 305/30R21 vs 265/30R22 (+0.20%)
- 295/30R21 vs 255/30R22 (+0.20%)
- 245/35R21 vs 295/25R22 (+0.20%)
- 255/50R21 vs 285/40R22 (−0.20%)
- 255/40R21 vs 295/30R22 (−0.22%)
Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.