size CIRCUMF. (MM) CIRCUMF. (INCH) DIAMETER
5 49 – 51 1 15/16 – 2 15.70 – 16.10
6 52 – 53 2 1/16 – 2 1/8 16.51 – 16.92
7 55 – 56 2 3/16 17.35 – 17.75
8 57 – 58 2 1/4 18.19 – 18.53
9 59 – 61 2 5/16 – 2 3/8 18.89 – 19.41
10 62 – 63 2 7/16 – 2 1/2 19.84 – 20.20
11 65 – 66 2 9/16 – 2 5/8 20.68 – 21.08
12 68 – 69 2 11/16 – 2 3/4 21.49 – 21.89
13 70 – 71 2 3/4 – 2 13/16 22.33 – 22.60