I tend to mash, so I intentionally keep my ratio low on my SS/FG bikes to force myself to spin. It's easier on the knees in town and it's good to get comfortable at a higher cadence out on the road. Typically, I'll do 42x16 for the road FG. My SSCX is at 41x18, which really makes me spin on flat tarmac, but it's as high as I can go on dirt and grass.