Originally Posted by
Fox Farm
Put an 11-25 or something like that on as a cassette with your 50/34 and you will have nearly the same big gear in the 50 / 11 as you would with a 52 / 12
Eddy dominated the spring classics with a 52x13.
50x13 is only half a gear easier than Eddy used and plenty for the rest of us, being pleasant for cruising speeds up to 30 MPH and sprints 40. Going down steeper hills tucking works well enough.
People did fine with 52x14 as the common top gear during the bike boom. I've run 50x13 for the last 16 years including a decade in the Colorado Rockies. The advantage over a smaller starting cog is that you get more in between for a given range, and cogs running 16-17-18-19 feel great on flat ground.
This ignores the applications of smaller cogs with smaller rings, where eschewing the fully-cross-chained combinations a 34 ring with an 11 starting cog is like having a double with a 39 ring and 13 starting cog or triple with a 39 and 14.
Noting that I've been playing with 50-39-30 and a 14-23 10 cog straight block. Having one cog jumps to the 21 cog is a little better than stopping at the 19, but the 22 is superfluous unless you're Lance time trialing up l'Alpe d'Huez and 13-26 or 12-23 is probably a better choice.