Originally Posted by papapapaof4
Just bought a new road bike and would like to have a better really low gear for those long hills. Is there any reason why one cannot simply replace the stock 12-26 rear cassette with a 11-32 mountain bike cassette to go with the 52-42-30 front gears?
You can do that, but if you do, that may not be all you need to do. From what I remember, most road rear derailleurs have a limit on the difference between smallest and largest cogs that they can handle, and so an 11-27 is about at the limit. Putting a mtn bike rear derailleur on there ought to work just fine.