Originally Posted by 70sSanO

Herein lies the issue with doubles in some circumstances.

For the vast majority, a compact, subcompact, or even a 1x is the best option. But for others, I imagine more prevalent with tourers and an extra 50lbs, a middle ring that will go the width of a cassette might end up being the weapon of choice for a lot of miles.

It has little to do with running some chart to demonstrate the same available ratios with less duplicates. It has to do what the the ease of use, and convenience, that makes it almost function as a 1x in a lot of situation. At those times, there is little care if the same ratio could be found elsewhere in the gearing.

Back in the 52/42 days, most of my time was spent in the 42t in hilly terrain, or even where there were a lot of lights. The 52t was great on flats and downhills with open road.

John