Quote Originally Posted by tiva View Post
You might want to check something as simple as the speed you're riding. When I first got my road bike, I was exhausted compared to how I felt riding my hybrid. Then I compared the average speeds: I was averaging 9 mph on my hybrid and 15 mph on my road bike. No wonder I was more tired: I was pushing myself a lot harder. I still have to make a conscious effort on my road bike to pace myself on longer rides; otherwise, I get tired too quickly.
Speed definitely is something to consider. I took my old bike out today and it was a much slower ride - 7 mph compared to the 15-19 I usually do on the same terrain with my carbon bike. I also ride my carbon bike differently: thinking about shifting, looking ahead, babying it a bit because I don't want to hurt it (it's so pretty!) and worrying about my pedals (Unclip right, lean right!)...on my old bike, which is heavier, slower tires, I just mosey on down the road, in the wrong position, and feel all sorts of lazy and easy on it.

Don't discount the stress part of it too. I personally get very stressed when trying something new, which can make the learning curve feel a bit steeper (ie: "Why can't I get this! I am a failure!" and all sorts of negative self talk). Honor your experience and the work that it takes, but also, take advantage of the experience of the LBS staff, and see if you can make it a happy thing to be on the bike.

Good luck!