How flat is your route Jardo? I find that I ride comfortably on the flat at somewhere between 18-22mph depending on wind, but around my 6.8m training loop, my fastest time so far is 3 times round in an hour and one minute, clocked an average speed of just under 19mph. I tend to do it twice one way, then once the other, although I'm gonna work on doing it twice one way twice the other as it's a nice varied route with plenty of interval training opportunities. Beats riding along a flat A road for 20 miles, turning around then coming right back, although I do spend about 30+ mins a day on my turbo at the moment doing interval training