Joined: Dec 2005
Posts: 1,383
Likes: 2
From: Boulder, Colorado
Bikes: Cinelli Supercoursa 69, Ritchey Breakaway Cross, Mondonico Diamond Extra 05, Coors Light Greg Lemond (built by Scapin) 88, Scapin MTB, Stumpjumper 83, Specialized Stumpjumper M4, Lemond Poprad 2001
Sounds like your derailluer may be not staying in the lowest cassette. If your small pulley is rubbing when it is in the lowest gear you need to shorten your chain. For a good method see Sheldon Browns web site. If you have a 39/27 then it is the same everywhere even in Australia or in the chronosynclastic infandibulum. Good luck.