are you trying to fit an 11spd cassette to it? when you say too big what exactly do you mean - i would expect that if you are trying to fit an 11spd cassette to a 10spd freehub (assuming that is what you have already) then the hub would be too small...
in theory the freehub would be compatible, but without knowing what the issue you are trying to solve is then i'm not sure if it is the right thing to buy! 
bridgtown cona testa tri team - proudly finishing at the back
most disturbing in lycra award, 2010, 2012, 2013