Setting Preload in Heavy-Duty Wheel Bearings
This SAE Recommended Practice applies to the four primary, large volume applications in the class 7-8 heavy-duty market place, as specified in SAE J1842: a. “N” trailer axle b. “R” powered rear axle c. “FF / FG” nonpowered front axle d. “P” trailer axle This document applies to on-highway applications. It is not applicable to those applications that exceed the GAWR ratings or the load line restrictions listed in columns “A,” “B,” and “C” of Table 1. Load lines are measured from the inboard bearing cup backface as shown in 3.4. This document establishes preload force values only. The methodology to obtain these force values must be determined by the fastener supplier and/or axle assembler. This document reviews the bearing system. It is NOT intended to prescribe (new or existing) axle and/or hub manufacturers’ ratings and/or specifications.
Rationale: This Recommended Practice is being Stabilized because it covers technology and procedures which are not likely to change in the foreseeable future. The bearing combinations addressed are mature designs.