2026-04-12 · sourcing
A clear breakdown of OEM, OES, aftermarket and genuine parts, with practical guidance on which tier to stock for which channel.
Genuine parts are produced for and sold by the vehicle manufacturer in OE-branded packaging. OEM parts are the same physical parts produced by the same Tier-1 supplier but sold without the OE brand. OES (original equipment service) is the OE’s spare parts division. Aftermarket parts are produced independently for the replacement market, with a quality range from premium-equivalent down to bargain-bin.
Genuine: dealer networks and high-end fleets that need warranty alignment. OEM: specialist independent workshops, premium e-commerce. OES: mid-market workshops. Aftermarket premium (IATF 16949, ECE R90, etc.): mainstream independent workshops, big-box retail, fleets focused on TCO. Aftermarket value: high-volume retail and emerging-market export.
Donвђ™t take supplier claims at face value. Insist on certificate copies that you can independently verify: IATF 16949 (Bureau Veritas, TÜV, etc. for the cert body), ECE R90 (issued by an EU type-approval authority), ECE R112 / R113 for lighting, E-mark numbering, and material test reports for cast iron and aluminum components.