I have asked this question before but I now have more info and am trying to ask a more informed question.
To begin with, I have a Trek 1200 with a 30-39-50 triple up front and a 12-25 in the rear.....and want lower gearing. Since I am older (55) and have two bad knees and other health issues I'm probably not going to get much stronger but do have a desire to ride the Blue Ridge Parkway and other terrain with similar hills.
Not that I dispute the gospel of Sheldon Brown/Harris Cyclery,but has anyone ever installed their '13-30 Century Special', which they claim can be used with any Shimano derailleur, and if so, how did it work out? Never having changed a cassette before, is this something I can do and/or does it take special tools?
Also, if that doesn't work, will I get much help from a 12-27?