I currently am running a compact (110mm) 52/38 FSA chainring. I have a big ride coming up in June in the mountains 100 mile 13000 ft of climbing. I am wanting to put a 34t inner ring on and am wondering what exactly I need to do. Are all brands compatible as long as they are 110mm? I have found some on ebay for around $20 just wondering if it would work. I don't want to spend a lot on it because it will be used very little, just want to make sure it will work without problems.
Spec' Tarmac (road), Ridley Fenix (commuter & fast tourer), Salsa Mamasita (MTB), CoMo Speedster (tandem), Surly Big Dummy (cargo), Airnimal (folder)
There is no need to change the big ring if you're prepared to put up with the big change in cadence when shifting. The 52-34 jump should work OK, but not super smooth. If you can install a Third Eye Chain Watcher or K-Edge Chain Catcher to prevent the chain from derailling off the inside then that would be a good safety precaution.
To get as low as gear as possible for those 20% walls then you could even get a 33 tooth inner ring, TA Specialites makes one, but many companies have 34 as their smallest 110 BCD ring.
once you are in that small gear , you need to be at the crest of the hill
and coasting down the other side to do that upshift, and in that low ring
there is a likely hood of dragging the chain against the side of the big chainring