I am replacing my 105 10 speed cassette on my Fulcrum racing 7 wheels with an Ultegra 6700 cassette, and am having trouble with the lockring. The current cassette is 12-23, and the new one is 11-25. The new Ultegra 11t lockring doesn't fit the freehub body. Is it possible for a free hub to fit a 12t lock ring and not an 11t? Also, do Fulcrum wheels use their own lockrings, b/c the current one on the wheels is black/generic looking and doesn't say "shimano" anywhere on it.