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The Evolution of Serpentine Belts

Why Belts have Changed and General Maintenance

The EvolutionofSerpBelts

Complicated Drive Systems Impacted Serpentine Belt Design

Over the past 25 years, serpentine belts have changed considerably. Vehicles used to have multiple serpentine belts that only had up to four points of contact. Today, serpentine belts can have over 10 points of contact, creating very complicated drive systems.

As OEMs continue to add accessories and look for the most efficient ways to power them, they’ve moved from multiple serpentine belts to one belt driving all the accessories. This was accomplished by working with belt manufacturers like Dayco to develop a technology that can handle high loading requirements while also providing an increase in durability under extreme temperature conditions.

The Benefits of EPDM Belts

Today’s serpentine belts are made to last longer than their predecessors – they shifted from being made with a neoprene rubber compound that generally lasted 50-60,000 miles before failure to being engineered with EPDM (Ethylene Propylene Diene Monomer) compounds. Belts made with EPDM have more elasticity so they are less prone to cracks and can last much longer – closer to 90,000 miles or more.

EPDM Belts and Issues with Noise

While serpentine belts made with EPDM have many benefits, they are also inherently stiffer than the older neoprene compounds – which means they can be less resistant to minor pulley misalignments that sometimes result in noise if not corrected. This is one of the reasons that noise is a bigger complaint today, especially in colder weather areas. If there is noise coming from a new belt, the majority of the time it’s NOT the belt but a misalignment or tension issue. A thorough inspection will help identify the culprit.

Serpentine Belt Maintenance

EPDM belts should be inspected for wear starting at 60,000 miles and worn components should be replaced at 90,000 miles. While the upside is that only one belt is required on newer drive systems, the downside is if that one belt fails, the vehicle will typically not run. So be sure to educate your customers on the importance of being proactive.

For more tips on maintenance and troubleshooting noise, check out our article, Diagnosing Serpentine Belt Noise