Just yesterday, I published TriRig's full review of the new Red group. It's an awesome set of hardware, but one of my major gripes had to do with the shifting hardware. SRAM's official position was that the old R2C shifters aren't ideal because of their inclusion of a trim position. I speculated that they'd soon remedy the problem with a YAW-specific R2C shifter. Soon indeed - just a day later, and SRAM has launched the YAW version of the R2C levers. I swear that at the time I wrote the review, I didn't know these were coming. Of course, if you have old R2C shifters and want to use them, you technically can. But SRAM warns that you'll have to go through the mildly annoying task of shifting past those trim positions on your way to the small or large chainring. The new shifter sliminates the trim positions, and makes for a much faster lever throw from one ring to the other. I used them on a demo bike, and can tell you it's actually a much bigger change than you'd expect. The throw feels much shorter, even though the cable pull is the same.
In my review of the original version, I described what a wonderful ergonomic experience it is to have these on the front of your bike, and how it really changes your shifting once you can grip around the front of the shifters without worrying about where the lever blade is going to end up. The new R2C shifters keep this ergonomic philosophy, but have updated internals on the front shifter that don't have trim positions.
In addition, the shifters now have a lighter action. SRAM had received complaints that the shifting was too stiff, and softened things up by revising the tooth profiles of the internal ratchet mechanism. There's also a second change to the shifter internals: a spring clip designed to hold the internal mechanism in place. The old version was susceptible to disassembly by ham-fisted mechanics who didn't read their instruction manuals. The new version is a bit more foolproof. But the changes don't add any real weight: the shifters are 175g combined.
YAW TT rings
In addition to the revised R2C shifters, SRAM has launched its first YAW-specific TT chainring. This version comes in a 55-tooth version, so unless you're mashing the big gears, you need to use the standard YAW chainrings, which are nothing to scoff at either. What makes a YAW chainring different from any other? Two things. One is the ramp and pin profiling that makes the chainring shift just that little bit better with the YAW front derailleur. The other is that the chainring itself sits just a tiny bit further outboard of the bike than standard chainrings. This is how the YAW setup avoids chain rub in all 20 gears, specifically in the small ring/small cog setup. If you have other chainrings you want to use with new Red and the YAW front derailleur, you CAN, but you might get a little rub if you're making the foolish mistake of crosschaining that badly anyway.