I really didn't have a solution but I had some suggestions.... Here is what I put in the email....

How loose is the side belt? I have had my car almost a year now and I have never had to change the side or rear belt. I have had to replace the front (main) belt about 3 times due to the 25T pulley being ground down on the left side so lossing the left side support causing the belt to slip off. But your side belt should not be stripping out. If your belt is tight, look at the 17T pulleys. The groves in them might not be deep enough for the belt groves and causing your belt to slip. If thats not the problem I would contact CEN and talk to one of there reps and see what they can do for you. Contact Mike...
Mike
[email protected]
714-792-1923 ext: 105
there is his email address and number with his extention. He helped me out on a package I received. I ordered the brake up-grade and it didn't come with the brake disk. It only came with the pad. I contacted him and he sent me a new part with out any questions or returning the other package. Also if you can send me pics. so I can see what might be the problem. I wish I could help you out more. Let me know what you find out.

Thomas