Originally Posted by Russ Roth

For my personal use gear inches hasn't been that significant. But my kids ride track, road and BMX and knowing gear inches has proven invaluable. I'm building a road bike for next year for my daughter and was trying to decide on the crank options 50/34 or 48/36. A quick look at gear inches and the 48t with a 12t small cog on the cassette with a 26" wheel with 28c tire will be only a couple inches under the max rollout allowed by USA cycling for junior riders. Saved me buying the wrong gearing. With track and BMX having a nice big gear inch chart printed out means I can pick the next closest gearing without having big changes to fine tune what's best for them.