From what I am reading on the net the “30” refers to the thickness of the bearings, from 00 to 50. So giving the fact that apparently these pieces wear off anyway (slowly but they do) apparently you will be able to use any others from 00 10 20 40 and 50 and the bike will “get used to it” with time without risking anything. Good to know also : apparently XS1100 use the same parts, we need to check but I suspect XS850 should use the same parts. Another tip : look for 2F3116563000 (without the spaces like in 2F3-11656-30-00) , I managed to find this page which apparently sells these parts, but I don’t know anything about this website so remain careful.