Shimano Dura-Ace CS-7900 10 Speed Cassette

The lions share of attention has gone to Shimano's awesome 7900 (standard) and 7950 (compact) cranksets, and the 7900 shifters. There's not a lot of glamour in the cassette category this year. Is this a bad thing? Absolutely not. It simply means that Shimano's engineers only needed to apply a few tweaks to match the awesome new technology seen on other 7900 Dura Ace components. It's almost like you've been riding 2009 technology for a year already.Make no mistake, there are changes that have been made, like stacking four titanium cogs on all sizes of cassettes this year. Just like the chainrings, the teeth of the cassette have been re- profiled to mesh perfectly with the new 7900 chain for smooth, quiet, seamless shifting unlike any you've experienced before. A new carrier also adds stiffness and reduces weight.Don't run the 11-27 or 11-28 versions with anything but a 7900 rear derailleur. All other 7900 cassettes will work with your 7800 rear derailleur, but you should probably just go ahead and upgrade that too.