Originally Posted by
KillerBeagle
Pardon a noobish question but what exactly is meant by a "compact double"?
I have a Stronglight 93 52/38 that I'm thinking of dropping to 50/38. It can't go any lower than 38 with 122 BCP, but I got around Germany and Luxembourg with it okay with a 14-28 freewheel back in the early 80s.
A typical road gearing for a crankset is around 52t/(42t-39t). A typical triple crankset might be 48/36/28. These are usually run with freewheel/cassettes around the 13-28 or so range.
A compact double usually runs more around 50/34 (16 teeth spread usually?), and is often run with wide cassettes (11-32). This way, you get the range of a triple crankset with a double front crankset. The reasons for wanting a double as opposed to a triple tend to vary for different people, but they're usually something like "it's simpler and lighter".