Originally Posted by
Paravia
I owned a bike with a triple in the past, totally redundant just more weight to carry. I have the same ratios now (actually more) with a compact double, easier/quicker to use and to maintain, so I don't see the point of a triple.
If you were seriously considering an 11x42 cassette, then a triple combined with a more closely spaced cassette is anything but redundant.
The closer spacing of the two larger rings is a major plus as is the ability to have a very low low gear without going to a dinner plate size largest cog and the huge gearing gaps those cassettes provide.
The weight penalty of the triple is negligible, certainly no more than that of having a 42T cog.