Frequently Asked Questions

A cogged v-belt is a v-belt that has notches on the inside of the belt. These allow the belt to have in increased flex range to accommodate smaller pulley diameters.

A v-belt that has an outside cover that protects the rubber from liquids, is used for clutching applications, and/or to increase durability.

A transverse fiber core is a v-belt’s core rubber compound that contains molecular fiber strands. These are transversely aligned to the running direction of the belt allowing it to flex vertically while reducing movement horizontally. A transverse fiber core increases durability, efficiency, and other aspects of a v-belts performance.

Power transmission industry tolerance standard for match belt lengths.

Two or more v-belts or wedge belts that have been joined together by a top layer of material.

An idler is used to keep tension on a belt in drive applications where space is constrained or there are long distances between pulleys. 

If the label or part number is worn, then 3 measurements are needed:

  • Top Width, measurement of the belts longest width
  • Depth, measurement from the top (widest) to the inside (narrowest) areas of the belt.
  • Outside Length, measurement of the outside circumference of the belt.

The top Width and depth are needed to determine the belt section.

Classic Section Sizes (A, B, C, D)(US standard): A: ½”w x 11/32”d,  B: 21/32”w x 7/16”d,  C: 7/8”w x ¾”d,  D: 1-1/4”w x ¾”d,  E: 1-1/2”w x 1”d

Standard Section Sizes (3V, 5V, 8V)(RMA/MPTA): 3V: 3/8”w x 5/16”d,  5V: 5/8”w x 17/32”d,  8V: 1”w x 7/8”d

Metric Section Sizes (SPZ, SPA, SPB, SPC)(mm): SPZ: 9.7mm w x 8mm d,  SPA: 12.7mm w x 10mm d,  SPB: 16.3mm w x 13mm d,  SPC: 12mm w x 18mm d

The measurement of the outside diameter is the length. Classical and Standard sections lengths are measured from the outside. Metric lengths are measured from the inside, but the outside circumference can be converted to an inside length. Contact an OPTIBELT service representative for assistance.