I have a few questions regarding derailleurs, cassettes, and cranksets, if you don't mind indulging me for a moment.

First off, I'm really confused about the cage lengths of rear derailleurs. Does the length of the cage have any relation/consequences regarding the cassette/freewheel, or does the length correspond more to the crankset chainrings?
If the latter is true, does it relate to the number of teeth (size) of the chainrings or to the number of chainrings (ie: 2 vs. 3 rings)?

Can a newer rear derailleur designed for an indexed shifting system be used with a friction shifter setup? In other words is the internal mechanism for the derailleur indexed, or can it shift in a continuous motion with friction shifters?

Regarding cranksets, is a compact design preferable? What are its advantages vs. drawbacks? Is there any real reason to have a triple on a road bike?

My last question is in regards to both the cassette/freewheel and chainrings. For the cassette/freewheel, does it really matter if the smallest gear has 11 vs. 12 teeth, or if the largest has say 27 vs. 28? Similarly, do the chainring sizes make much of a difference, aside from matching the front derailleur profile?


I am working on a road bike project this summer, and am starting with a bare frame, so I would like to have a better understanding of what I'm putting together so that the transmission will function properly when I'm finished. I will post pics during the build for certain.

Thanks!