Now, one last question. Assuming that I simply replace my current SRAM 9-speed cassette with another 9-speed one - probably a Shimano Tiagra HG50, will I need to replace anything else? From what you guys have told me, I will be able to use my existing rear derailleur (Shimano Deore) and shifters (Shimano R440). How about the chain? Now that my biggest cog will be smaller (30T vs 34T), will I need to get a shorter chain?