BB Double-Sided V-Belt Size Chart

BB Double Sided V Belt Size Chart

What Is a BB Double Sided V Belt?

A BB Double Sided V Belt, sometimes called a BB hex belt, has V shaped driving surfaces on both sides. Unlike a conventional V belt, which is designed to engage pulleys on one side, a double sided V belt can transfer power through either side when used with a properly designed pulley arrangement.

BB belts have a top width of approximately 0.656 inches, or 21/32 inch. This larger section provides a heavier profile than an AA belt and is commonly used in power transmission applications that require a double sided belt with greater capacity. The BB designation identifies the belt section, while the number that follows identifies the nominal belt size. For example, BB42 has a listed outside length of 46.6 inches, not 42 inches.

Outside Length vs. Belt Part Number

The number in a BB belt part number should not be mistaken for its outside circumference. For the BB sizes listed here, the outside length is 4.6 inches greater than the number in the SKU. For example, BB60 has an outside length of 64.6 inches, BB100 has an outside length of 104.6 inches, and BB200 has an outside length of 204.6 inches.

If you are replacing a worn belt, check the printed part number if it is still legible. If you are measuring the belt instead, confirm which length measurement you have and compare it with the equipment manufacturer’s specifications. Outside length, inside length, and effective or datum length are different measurements and should not be used interchangeably.

Common Applications for BB Double Sided V Belts

BB Double Sided V Belts are used in agricultural machinery, lawn and garden equipment, material handling systems, industrial machinery, and other equipment with serpentine pulley arrangements. Their two driving surfaces are useful in systems where one belt must drive multiple pulleys or where pulley rotation changes direction throughout the drive.

Before ordering, verify the BB belt section, original part number, outside length, pulley groove compatibility, and equipment requirements. An ordinary single sided B section V belt is not automatically an interchangeable replacement for a BB double sided belt.