US INCHES MM UK FRENCH GERMAN

5 1  15/16 49 J 1/2 49 15 3/4

6 2  1/16 51.5 M 51 1/2 16 1/2

7 2  3/16 54 O 54 17 1/4

8 2  516 56.6 Q 56 3/4 18

9 2  7/16 59.1 R 1/2 59 1/4 19

10 2  5/8 61.6 T 1/2 61 3/4 20