If they're wearing just on the end of the shoes with the adjuster, they weren't properly set up. There's a major adjustment required which involves loosening the anchor bolt at the top with the adjuster tightened completely, then tapping the anchor pin and or backing plate to center the shoes. The anchor bolt has a vertical slot to allow the top of the shoes to be adjusted up or down. The procedure is in the shop manual, and is done before the final adjustment of the star wheel.
