Hi SpecialK,
One other thing you may want to consider is a recovery drink for after your ride. I thought they were crap for a long time - then I finally tried one and it makes all the difference in the world. I bring this up because I will actually drink a watered down version during a ride to keep my energy levels up. I use Endurox orange. Another suggestion - are you eating anything during your ride - you might want to try GU, if you haven't tried any before I would recommend the vanilla or chocolate (they taste like frosting, yumm). Make sure you follow them with lots of water and take one package about every 45minutes to an hour. Good luck!