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Convert Sizes By Country
Diameter (mm)
diameter (inches)
circumference (mm)
circumference (inches)
British/Australian
19.41
9.91
0.39
31.13
A - 3
19.51
10.72
0.442
33.68
A - 2
19.62
11.53
0.454
36.22
A - 1
19.84
11.95
0.474
37.54
A
20.02
12.18
0.482
38.26
A 1/2
20.2
12.37
0.487
38.86
B
20.32
12.6
0.496
39.58
B 1/2
20.44
12.78
0.503
40.15
C
20.68
13
0.512
40.84
C 1/2
20.76
13.21
0.52
41.5
D
20.85
13.41
0.528
42.13
D 1/2
20.94
13.61
0.536
42.76
E
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