Hi

I want hills to be as easy as possible, and am already using compact chain rings, but my rear cassette is standard shimano ultegra and has a big gear of 27. The biggest three gears come in an assembly so you can't just change the big gear individually. Is there any way that I can get 29 or 30 for my biggest gear in an Ultegra compatible arrangement. Will this have any implications for chain length etc.

Davida