OEM and private-label V-belt sourcing requires more than approving a nominal size and logo. This guide explains how buyers should define V-belt length references and tolerances, specify matched sets for multi-belt drives, control private-label marking and packaging, evaluate factory inspection capability, and prepare a complete OEM RFQ. It also shows what evidence procurement teams should request before moving from an approved sample to repeat production, helping reduce dimensional, branding, batch-consistency and purchasing risks.