I just rode a 30 mile ride for the first time today. I did it in 3 hours, averaged just under 10 mph which is kinda disappointing for me. Ive been averaging close to 12 mph on rides up to 15 miles. What would be good training exercises to get my speed up? I am working on my goal to do the 90 miles with the livestrong challenge in october. I just dont know where to turn to for help.