Leading the world in bearing adjustment technology                                                                ...for over 40 years 1-518-853-3467 Temper Axle Products Corporation PO Box 1127  -  Fonda, NY 12068 USA Certified ISO 9001 - 2008 and AS 9100 E-Mail Us CHOOSING PRELOAD OR ENDPLAY: The fastest and most accurate procedure can be achieved with Doctor  Preload tools. Small values of endplay can be achieved with the Temper Endplay Measuring Tool (EMT) with  accuracy and reasonable speed.  This tool can be used to diagnose problem wheel settings before proceeding with  corrective maintanance. Initial investment for handling all four of the most popular axle sizes is a bit lower for the  EMT as compared with the four separate Doctor Preload tools. Therefore the EMT may be more advantageous for  smaller maintenance operations. In either case our customer praise the quick recovery of their initial investments in  these tools. DOCTOR PRELOAD: Bearing manufacturers show that the best life of wheel-end bearings is always achieved  when set at light preload. In 2002 the Society of Automotive Engineers (SAE) created the standard designated SAE  J2535 specific to heavy-duty truck wheels that calls for adjusting steer axle bearings to 250 pounds and drive and  trailer axle bearings to 500 pounds preload. The first accurate implementation of that standard began in 2009 when  Temper introduced Doctor Preload tools used with Temper-Loc Spindle Nuts. The advantages were announced in  the SAE Journal in September 2009.  ENDPLAY ADJUSTMENT: The Technology and Maintenance Council (TMC) of the American Trucking Association  created the standard procedure RP 618A to address the need for a safe procedure for setting truck wheels with  either jam nuts or single nut systems. This standard adopts an acceptable setting range of 0.001 to 0.005 inches of  endplay, and employs a torque wrench to achieve a starting target setting, followed by a specific mandate for  measuring endplay results and making needed adjustments to assure that the setting is within the acceptable limits. MEASURING ENDPLAY: Typical measurement has been done with a dial indicator rigged up to evaluate wheel-  hub deflection when the hub is pushed and pulled along the axis of the axle. Temper developed the Temper Endplay Measuring Tool to make this operation much easier and much quicker. This tool can be applied with or without  removing the rim and tires, a major advantage for many checking and maintenance procedures. ABOUT TORQUE: The typical procedures that employ torque wrenches to establish target settings are sometimes  used as though they were accurate for final adjustment without using a measurement for verification [this is a most  hazardous procedure and often leads to premature wheel failure] Torque settings are widely variable, and  rely on calibration accuracy of the wrench as well as freedom of thread surface flaws on the axle and nut. With jam  nut procedures we typically see a chang of 0.008 to 0.012 inches of tightening during the application of the jam nut  after that traget setting is made with the inner nut. CALL US AT TEMPER COMPANIES FOR MORE INFORMATION (518) 853-3467