Another way to do it is if you know your race pace and sprinting speeds, calculate the gear from the cadence you feel comfortable at maintaing those speeds.
Using the above chart, 48x15 with 170 cranks and narrow tubs @100rpm is 25.3mph and 48x16 @100rpm is 23.7, so one of those two for me depending on weather.
Another way to do it is if you know your race pace and sprinting speeds, calculate the gear from the cadence you feel comfortable at maintaing those speeds.
Using the above chart, 48x15 with 170 cranks and narrow tubs @100rpm is 25.3mph and 48x16 @100rpm is 23.7, so one of those two for me depending on weather.