Originally Posted by spindle
so downtube shifters, thumb shifters, bar end shifters, they all seem to work on pretty much the same principle and to make a good deal of sense. brake-lever integrated shifters, though, how the hell do they work? could someone please explain what's going on inside those things to this curious individual? thanks.
Same principle: levers pull or release cable tension. It's just the way they are jury-rigged to do this that's different. Generally speaking, there's a ratchet mechanism which spools the cable up as you push on a lever. Then there's a clutch, pawl or ratchet-stop of some sort that can be released to slacken the cable. The only "tricky" part is packaging it all into a compact enough space with the proper linkages to allow you place everything into one unit.