Wheel End Bearing Settings
According to The Timken Company, proper wheel-end bearing setting is important for maximizing bearing, seal and tire life. Poor wheel bearing adjustment is a costly problem for the trucking industry. When a bearing is damaged due to improper adjustment, it is costly for the operator and everyone else. If properly adjusted, wheel-end bearing setting should not change significantly during early operation. For conventional nut-adjusted wheel-ends, The Timken Company recommends following the Technology & Maintenance Council’s (TMC) Recommended Practice RP 618. The company does not specify wheel bearing service intervals, since trucks are used for many different service duties and vocations. Users should follow their axle manufacturers’ guidelines.
The best practice to monitor wheel-end bearing setting is found in Step 8 of RP 618:
- Each time any maintenance is performed
- When anything looks peculiar or appears worn, hot or stained
- When any wheel-end component is inspected or replaced
This includes, but is not limited to:
- Brake jobs
- Tire changes
- Lubrication changes or checks
- Hubcap removal
- Maintenance or replacement of S-cams or bushing
- Abnormal tire wear
- Seal leaks
If there is an increase of end play in the wheel-end, a thorough investigation of the entire system should be carried out and documented.
Early detection of wheel-end problems could save fleets from unnecessary downtime say the experts at Timken. Check wheel-ends by doing a walk-around inspection and make sure to ask the driver what he or she may have noticed. Bearing wear may have already started if you notice:
- Abnormal or uneven tire wear
- Smoking or extremely hot hub cap (too hot to touch)
- Wheel vibration, wobble or noise
- Increased stopping distance or decreased braking power
- Abnormal side pull when brakes are applied
- Wheel lock-up or skidding
In selecting the best maintenance intervals for your fleet, first look at the maintenance schedules and service life experiences for your tractor/ trailer wheel-ends (brakes, hub caps, tires, seals, lubricant, bearings, spindle nuts, etc.) Choose components with performance records that compliment your preventive maintenance programs. If a component requires unscheduled service, a shorter inspection interval may be required.