Note:

• Circum = Circumference
• MM = Millimeters

Size	Circum in Inches	Circum in MM	Diameter in Inches	Diameter in MM
5.0	1.94	49.3	0.61	15.7
5.5	1.98	50.3	0.63	16.1
6.0	2.04	51.8	0.64	16.5
6.5	2.09	53.1	0.66	16.9
7.0	2.14	54.4	0.68	17.3
7.5	2.18	55.6	0.69	17.7
8.0	2.24	56.9	0.71	18.1
8.5	2.29	58.4	0.72	18.5
9.0	2.34	59.5	0.74	18.9
9.5	2.39	60.9	0.75	19.3
10.0	2.44	62.1	0.77	19.8
10.5	2.50	63.5	0.79	20.2
11.0	2.54	64.6	0.81	20.6
11.5	2.59	66.0	0.82	21.0
12.0	2.64	67.2	0.84	21.4
12.5	2.69	68.5	0.85	21.8
13.0	2.74	69.7	0.87	22.2
13.5	2.79	71.0	0.88	22.6