27~75 gear inches is about all I need.
60 GI would be about ideal for me. can hit 40km/h should I need it, but with a really ideal 28km/h @ 100rpm range.
not too tall at stop and go, yet tall enough to keep up with city traffic by hitting 35km/h
40km/h = 25mph. I don'tthink you can do that with 60 G.I. since you would need to be spinning at around 140RPM!