Full definition
The precisely machined V-shaped channel in a pulley where a V-belt sits and transmits power through sidewall friction (wedging action). Key dimensions per ISO 4183 and DIN 2211: groove angle (34-38° depending on pitch diameter and profile), groove depth, and groove spacing (center-to-center distance for multi-groove pulleys). The belt must contact only the groove sidewalls, never the bottom — a belt bottoming out in the groove cannot develop proper wedging force and will slip. Groove wear indicators: polished/shiny sidewalls (glazing), groove wider than specification (check with a groove gauge), belt riding lower than new position, visible rust or scoring. Groove surface finish: Ra 1.6-3.2 μm. Material buildup from worn belt rubber must be cleaned periodically. Replace the pulley when groove dimensions fall outside tolerance — typically after 2-3 belt change cycles. Each V-belt profile has specific groove dimensions that are not interchangeable.