Beware aluminum underdrive pulley.
I finally fixed my squeaky belt problem....after roughly one year of squeaking. Turns out my under drive pulley was not gripping the belt very well.
I replaced the pulley with my stock one, then took a closer look at the under drive's grooves. The grooves were obviously worn. The transitions between the peaks and valleys were parabolic shaped, as opposed to straight lines. When matching the belt to the pulley, the belt grooves were bottoming out in the valleys reducing the hold on the belt.
I'm not trying to bash a brand or the product, just sharing my experience. I'm not surprised the pulley wore out since aluminum is a softer metal then steel. FYI, I've been using the pulley for ~4 years
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