Full definition
The engineering process of choosing the correct V-belt cross-section (profile) for a given application, based primarily on design power and smaller pulley RPM. Procedure: (1) calculate design power (rated HP × service factor); (2) enter manufacturer selection chart with design power on Y-axis and faster shaft RPM on X-axis; (3) the chart region determines the recommended profile (e.g., SPZ/3V for light, SPA/A for medium-light, SPB/B/5V for medium, SPC/C/8V for heavy). Using too small a profile results in too many belts, excessive cost, and wide pulleys. Using too large a profile means oversized pulleys and wasted space. Per ISO 1081, ARPM, and manufacturer catalogs (Gates, Optibelt, Continental). Narrow profiles (3V/5V/8V and SPZ/SPA/SPB/SPC) are preferred over classic (A/B/C/D) for new designs due to higher power density and space savings.