A Belt Guide - A Section V-Belt Sizes, Dimensions & Cross Reference

The A-section is an industrial-grade V-belt measuring 1/2" wide x 5/16" tall. A belts share the same cross-section as 4L FHP belts but are built for heavier industrial applications with reinforced construction. Whether you are replacing a worn drive belt on a pump, motor, or HVAC fan, the A belt delivers dependable power transmission across a wide range of equipment.

A Belt Specifications

Specification Value
Top Width 1/2" (12.7mm)
Height 5/16" (7.9mm)
Belt Angle 40°
Minimum Pulley Diameter 3.0"
Length Range 26" to 180"+ (inside circumference)
Construction Industrial rubber with polyester cord

Understanding A Belt Part Numbers

A68 = A-section belt, 68" inside length. Unlike 4L belts which use outside length, A belts are measured by INSIDE circumference. An A68 and a 4L700 are the same physical belt measured differently. To convert: the A belt inside length plus approximately 2" equals the 4L outside length.

A vs 4L Belts: Side-by-Side Comparison

Feature A Belt 4L Belt
Top Width 1/2" 1/2"
Height 5/16" 5/16"
Measurement Method Inside length Outside length
Part Number Example A68 = 68" inside 4L700 = 70" outside
Grade Industrial Fractional Horsepower (FHP)
Interchangeable? Yes — same cross-section, different naming convention
Conversion A size + ~2" ≈ 4L outside length

Common Applications for A Belts

A-section V-belts are widely used across industrial and commercial settings, including:

  • Industrial motors — general-purpose single and multi-belt drives
  • Pumps — centrifugal, positive displacement, and irrigation pumps
  • HVAC fans and blowers — air handling units and exhaust systems
  • Air compressors — reciprocating and rotary screw compressors
  • Machine tools — lathes, drill presses, and milling machines
  • Agricultural equipment — augers, feed conveyors, and processing machinery
  • Conveyor systems — light to medium-duty material handling
  • Manufacturing equipment — packaging, printing, and assembly line drives

How to Measure an A Belt

A belts are measured by inside circumference. Wrap a flexible tape around the inside of the belt (the side that contacts the pulley groove) and read the measurement in inches. This number is the A belt size. For example, if the inside measures 68 inches, you need an A68.

If the belt is broken or stretched, measure the pulleys center-to-center and use an A belt length calculator, or visit our complete V-belt measurement guide for step-by-step instructions.

Shop A Belts at EVbelts.com

We stock a full range of A-section V-belts from A26 through A180 with fast shipping.

Popular sizes: A26, A48, A68, A75, A90, A120

Browse All A Belts →