I ride for fitness and the occasional tri. The one thing I was told from a really good local trainer was to ride with a high cadence and low resistance and speed would come. It has worked. I used to be a 14-15 mph gal and now it's 18-20 steady. I vary my rides with distance. Some days are longer and high cadence the whole time and shorter rides I throw in haul-*** sprints in a bigger chainring. I can maintain up bridges (thats all there are here in Miami) with the big guys. Good luck, you'll be smokin him in no time!