What's the difference between tier 1 and tier2?

Automobile tier 1 and tier2 refer to auto parts suppliers, and their differences are as follows: 1, Tier 1: First-class suppliers of automobile factories directly supply vehicle manufacturers, forming a direct cooperative relationship. First-class suppliers not only directly supply assemblies and modules to OEMs, but also participate in each other's R&D and design together with OEMs, so they are the most involved suppliers in the whole vehicle manufacturing process. 2. Tier 2: Tier 2 suppliers mainly provide supporting equipment and spare parts to Tier 1 suppliers. Most secondary suppliers produce professional assembly systems and modular disassembly parts. Some products of leading enterprises at this level have reached the international advanced level and are in the stage of rapid development.