Accessory Drive Belt

What Is an Accessory Drive Belt?

The accessory drive belt — commonly called a serpentine belt or V-belt — is one of the hardest-working components under your hood. Driven by the engine's crankshaft, it transfers rotational power to the alternator, power steering pump, air conditioning compressor, and in some vehicles, the water pump. Without a functioning accessory drive belt, these critical systems simply stop working, which can quickly leave you stranded or cause serious engine damage from overheating.

Modern engines typically use a single serpentine belt that snakes around multiple pulleys in a continuous loop. Older designs may use two or more individual V-belts, each dedicated to a specific accessory. Regardless of belt type, the underlying principle is the same: a flexible rubber belt under precisely calibrated tension keeps every accessory spinning in sync with the engine.

Signs Your Drive Belt Needs Replacement

• Squealing or chirping noise from the front of the engine, especially on startup or during sharp turns
• Visible cracking, fraying, or glazing on the belt surface
• Warning lights for the battery, power steering, or temperature gauge indicating an accessory has stopped functioning
• Mileage — most manufacturers recommend inspection after 60,000 miles and replacement around 90,000 miles, though this varies by vehicle

Because the accessory drive belt works as part of a larger system, it's generally recommended to replace the tensioner and idler pulleys at the same time as the belt itself. Worn pulleys and tensioners accelerate belt wear and can cause a new belt to fail prematurely.

Top Accessory Drive Belt Brands

Bando is a leading supplier of automotive and industrial power transmission belts, drawing on deep OEM manufacturing experience. Bando accessory drive belts are engineered with flexible, oil- and heat-resistant backing for extended service life and offer extensive coverage across both domestic and import vehicle applications.

Dayco has been a global leader in drive belt manufacturing since 1905 and is widely recognized as a pioneer in accessory drive belt technology. Dayco belts are built with thermally active tensile cords for maintenance-free performance and are engineered to minimize noise, vibration, and harshness — making them a trusted choice for both DIYers and professional technicians.

ContiTech, the automotive division of Continental AG, brings over 140 years of rubber product expertise to every belt it produces. Known worldwide as an OEM supplier to many leading European automakers, ContiTech accessory drive belts are manufactured using advanced EPDM rubber compounds that resist heat, cracking, and elongation — and are available in convenient complete-kit configurations for easier servicing.

Choosing the Right Accessory Drive Belt

When selecting a replacement accessory drive belt, always confirm the correct belt profile (serpentine/multi-rib or V-belt), rib count, and length for your specific year, make, model, and engine. Using a vehicle fitment tool ensures you get an exact match the first time. It's also worth considering whether your vehicle's tensioner and idler pulleys are due for replacement at the same time — servicing the complete drive system in one pass is both more reliable and more cost-effective in the long run.