If that was the case with your Belt being so TIGHT. run a XRAY T@ belt, it has 2 more teeth and give you more play. But i would have to say that the belt was made wrong or packaged wrong to be that tight/.
I break in every new car, belt and Bearing for a minimum of 3 to 4 hours , and my car and free wheel for a long time, and is as smooth as glass.
Just my .2 cents worth