This SAE Recommended Practice applies to upper coupler kingpins for commercial trailers and semitrailers conforming to the dimensional requirements of SAE J700 when new and originally installed. The dimensions of SAE J700 are the frame of reference for this document.

The purpose of this document is to establish maximum parameters for kingpin wear and to suggest a gauge configuration for inspecting kingpin wear. Kingpins exceeding the conditions of this specification must be removed from service and replaced.