It might be worth you taking the bike to a dealer or garage where they can get an airgun onto it - especially if it's the first time that the sprocket will be removed since new - they're put on fecking tight at the factory and sometimes even a breaker bar on a 1/2" drive socket and a smack with a lump hammer won't shift them > - an airgun will whizz it straight off - get it loosened, then tighten it sufficiently to get you back home to do the work [smiley=thumbsup.gif]