I have no desire to race, but I would like to increase my speed. I've worked to get my base mileage up - can do a century without a problem, and my regular rides are at least 80 miles. But, my average speed is only about 15.5 over the century. I would like to get my average speed up. I like doing long rides - I love the amount of calories that I can burn and just being on the bike for hours and hours, so I would like to incorporate the long distances into my attempt at getting faster. I have no clue what my VO2 max is, or my LT, but would like general tips on how to go about it. Do I just go out and try to maintain a faster rate for my entire 80 miles? Do I add intervals - at the beginning of the ride, middle, or at the end? Do I alternate days, doing long rides one day, work on speed the next? Help!