Temper Axle Products Doctor Preload bearing adjustment tools allow technicians to quickly and accurately set wheel bearings to measured industry standards for light preload settings to dramatically increase tire life and eliminate uneven wear at all tire positions. Preload eliminates axial movement of wheel seals and therefore reduces premature seal leaks and failures. Fleets are converting every wheel end to preload adjustment with Doctor Preload and dramatically reducing tire expenditures, according to the company. Temper offer significant improvements in cost and performance that were lost with bearings set to endplay. Made in U.S.A.