Serpentine belt

To accommodate this bidirectional flexing while remaining strong enough to transfer the total force required by multiple loads, a serpentine belt is almost always of multi-groove (multi-vee, poly-v, or multi-rib) construction.

This is typically limited to components requiring less torque or where a large angle of wrap is present.

Higher tension reduces slip, which increases belt life and mechanical efficiency.

[2] The belt typically gives ample visual warning of impending failure, sometimes even totally shedding several grooves (ribs) while continuing to function acceptably.

Furthermore, the loss of function of a single component (such as a power steering pump or air conditioning compressor) causes the failure of the entire accessory drive.