Originally Posted by Doge

As my kid has to run lower gears the typical setup is 45X12 or 52X14. Bigger cogs are better. Tony Martin used them for winning world TT. They put less chain tension, less frame flex, less friction, and less wear.
There are (now) 11speed options that are every bit as good as the DA options. We use the solid 1 pcs RECON 14-27 (125g) for racing and Shimano Ultegra 14T-28 for training. With 52 front. I get most olders do not rev like kids, but a 54X13 should do for most rides (what I ride), don't you think?