Do you have irregular tire wear? If so, you may be thinking it’s a wheel alignment, tire inflation, or axle issue because that’s what we’ve all been led to believe. Well, it’s time to let in some new information: irregular tire wear is often caused by improper bearing adjustments.
What we use:
Why Doctor Preload:
SAE International, the technical and engineering leaders of the vehicle industry, published the specifications for light preload in heavy duty truck and bus wheel end bearings for optimal performance in March 2001. At that time there was no practical and safe way to adjust bearings to SAE specified preloads – until Temper Axle introduced Doctor Preload to the industry in 2009. Now there are no more excuses:
- No reason to compromise wheel end and tire performance with outdated and cumbersome procedures.
- No reason for you to settle for poor performing wheel ends and tires.
- Absolutely no reason to leave that money on the road.
Fleets report achieving up to 30% increases in tire life due to more even tread wear. Wheel seal and bearing life and brake operation are also optimized with preload settings.
What is preload?
Wheel end tapered roller bearings are designed to be set to preload. They are not designed to be “loose” or have endplay. In preload condition, all clearances (endplay) between components in the wheel end assembly are completely eliminated and the bearings are slightly compressed.
Keeping a light preload force on the bearings maintains roller alignment so they roll the way they should. The rest of the wheel end components including tires, seals, and brakes are all designed to work best under preloaded bearing settings.
Preload is not Pre-adjusted: “Pre-adjusted” is a term that refers to wheel ends with a cone spacer and higher cost “close tolerance bearings” that will set to endplay and reduce tire life. They cannot be adjusted to a better setting, without removal of the cone spacer.
Preload is not torque: Torque should never be used to adjust bearings to a presumed preload condition because the final preload setting cannot be measured, thus creating unsafe inconsistency in bearing settings.
Is endplay hurting my fleet?
Yes: The more endplay, the more money you’ll spend on vehicle operation and maintenance. Bearings set to any amount of endplay, as small as a few thousandths of an inch, cause rapid and irregular tire wear, resulting in shorter tire and tread life. Developed by tire and chassis engineers, the Radial Tire Conditions Analysis Guide, Technology & Maintenance Council (TMC), Fourth Edition, identifies 14 different common irregular tire wear patterns that are caused by improper bearing adjustment. Setting to preload helps solve these problems. By removing endplay and setting bearings to preload, irregular wear is reduced or eliminated, enabling optimum tire performance and leaving less money on the road.