V-Belt Cross Section Chart

What it is

A V-belt is identified by cross section and length. North American industrial belts come in three families, each with its own ARPM (formerly RMA) standard:

• Classical: A, B, C, D and E (ARPM IP-20).
• Narrow: 3V, 5V and 8V (ARPM IP-22). Deeper and narrower; more power in less space.
• Light-duty / FHP: 2L, 3L, 4L and 5L (ARPM IP-23). Single-belt fractional-horsepower drives.

Cogged versions add an X (AX, BX, 3VX, 5VX). Banded belts join several belts with a common top band.

How to use it

• Read the part number on the belt. Letters are the section; numbers are the length.
• If the print is gone, measure the top width with a belt gauge or calipers and match it to the chart. Check the depth too: narrow belts are deeper than classical belts of similar width.
• Measure the sheave groove with a groove gauge. Belt and sheave must be the same family.

Section chart

Key points

• Same top width does not mean same belt. 4L and A share a width, as do 5L and B, but FHP belts are not rated for industrial multi-belt drives.
• Narrow (V) belts need narrow-groove sheaves. Some classical sheaves are built to accept both, but check the sheave maker.
• Metric belts (SPZ, SPA, SPB, SPC and Z, A, B in ISO 4184) are close to some inch sections but not identical. Confirm before swapping.
• Replace multi-belt sets as matched sets.

Common mistakes

• Comparing lengths from different families without converting.
• Putting a 3V belt in a classical A groove because the widths look close.
• Ignoring worn sheave grooves.

Governing standards: ARPM IP-20 (classical); ARPM IP-22 (narrow); ARPM IP-23 (light-duty); ISO 4184 (metric); belt and sheave maker data.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.