Originally Posted by Sy Reene

So, I assume you have a 10-speed drivetrain. A 13-29 would work if you can find a 10-speed cassette and your RD can work with this. I was in a similar situation.. 53/39 and a 12-25 and wanted some lower gears; but was on a 10 speed. I didn't feel that just switching to a compact, or just changing the cassette (and probably would have required a longer-caged RD) was going to cut it. A 39/25 vs. a 39/29 will not change your life. In the end, just bit the bullet and updated the entire groupset because it wasn't too much more expensive and a bit prettier.