'97 Eclipse RS, "Belt Shredder"

Ok, as some of you may have read; I have recently installed an underdrive pulley. I did this because I thought the harmonic balancer was bad (the rubber was splitting and the grooves were damaged in places)...
Well, I have had the car running two days with this new pulley, and it has already shredded another belt (the hb shredded a/b 4 in three weeks)...
I'm pretty clueless... I tightened the belt and let it sit for 5 minutes after installing (to "seat" properly)...
I noticed that this usually happens when I'm turning corners and accelerating... I'm unable to see what is causing the problem though...
Any ideas???


P.S.-A little history, with the harmonic balancer in place, the car would completely flip the alternator belt inside out, it would then not seat in the grooves and it would eat at the edge of the belt, the belt would then become a shredded mess... this happened to two belts... I would stop the car after hearing the belt flip over (not knowing at the time what had happened)...
I could usually roll a belt right off of the pulleys if I revved to red line a few times, I'm not sure why it's doing this...
I don't wanna sound stupid, but I don't think that they are too loose...
please enlighten me...

Pulley might be loose maybe? When the belt's off try rocking the pulley by hand to see if it has any play to it. Other than that I'm clueless, too. Also, if the alternator belt came off that easily then it was probably installed one groove over, or not the right belt. Once properly seated, those grooves are hard to slide off of.

I'll give that a try... I don't think it is, but I did just install it...
thanks, and I'll be sure to get back to ya