In the flatwoods of fla, I run a 53x17 (82 GI) so as to keep up on group rides. However, I do have a fixed commuer/tourer that's gear as much as 10 GI's lower.

From my observations, its seems that 74 GI is a very common gearing, so get a 17t and 16t cog and experiment.

Heres a few gearing links.

http://www.ctc.org.uk/resources/Abou...e/GEARTABL.XLS
http://software.bareknucklebrigade.c...it.applet.html