One of the leading complaints in regard to belts is noise, caused by misalignment, slippage, a lack of tension, belt wear and poor design. The new ACDelco V-Ribbed Belt with Advanced Technology features a patented design incorporating EPDM rubber that helps prevent stretching and improves backside wear. The result is quieter operation and longer life than previous belts. In all, ACDelco will have released 517 new part numbers in its belts and hoses line by the end of 2007, covering molded coolant and heater hoses, timing belts and tensioners, HD tensioners, and idler pulleys, as well as the V-ribbed serpentine belts. More than 313 of the new part numbers are Fleet Runner Belts – new long-life belts made primarily for medium and heavy-duty trucks.