Size guide
| Diameter In mm | Circumference In mm | Australia & Newzealand | USA & Canada |
|---|---|---|---|
| 15.1 | 47.43 | I | 4 1/2 |
| 15.5 | 48.69 | J | 4 3/4 |
| 16 | 50.26 | K | 5 1/4 |
| 16.3 | 51.2 | L | 5 3/4 |
| 16.7 | 52.46 | M | 6 1/4 |
| 17.1 | 53.72 | N | 6 3/4 |
| 17.4 | 54.66 | O | 7 1/4 |
| 17.7 | 55.6 | P | 7 3/4 |
| 18.1 | 56.86 | Q | 8 1/4 |
| 18.5 | 58.11 | R | 8 3/4 |
| 18.9 | 59.37 | S | 9 1/4 |
| 19.4 | 60.94 | T | 9 3/4 |
| 19.8 | 62.2 | U | 10 1/4 |
| 20.3 | 63.77 | V | 10 3/4 |