When SRAM launched its single-ring, 11-speed, wide-range drivetrain in the summer of 2012 it took quite a few years for the technology to trickle its way down to the entry level groupsets, and it also took some time for the single-ring revolution to really run its course. With 12-speed Eagle, it’s only been two years, and in that short time frame it seems like it has become the go-to standard for many a bike build, at least when it comes to OEM spec on mid- to high-end models. With Shimano finally joining the 12-speed party, and e*thirteen now making a...