Wheel End bearing adjustment products for heavy duty vehicles. Temper®-Loc premium spindle nuts are easy to use and cost effective. Temper Endplay Measuring Tool enables easy and accurate endplay measurement, and adjustment to desired endplay setting. Doctor Preload® is the fastest method for adjusting bearings to a light preload setting. Reduced maintenance costs, longer life for bearings, seals and tires, and improved fuel efficiency are the results.