Keeping your wheel hubs running safely starts with worn-part replacement done right. The Lippert 124287 is a direct-replacement inner bearing race engineered for 5,200 to 8,000 lb capacity RV and trailer axle hubs. When your inner race shows pitting, scoring, or heat discoloration, this is the part to reach for -- and since races and cones wear as a matched set, plan to replace both together every time.
The inner bearing race is the hardened steel ring pressed into the wheel hub that the tapered roller bearing cone rides against. Over time, road vibration, heat cycling, and marginal lubrication cause microscopic fatigue on the raceway surface. A worn or scored race will destroy a new bearing cone in short order -- which is why best practice is always to replace the race and cone as a matched pair during any hub service.
Lippert part 124287 matches manufacturer reference number 25520, a widely used inner race dimension on medium-to-heavy RV axle assemblies rated from 5,200 lb to 8,000 lb. This covers a broad range of travel trailers, fifth wheels, and toy haulers running Lippert axle systems in that load range.
Specifically sized for 5,200 to 8,000 lb rated axle hubs -- fits the range most common on mid-to-large travel trailers and fifth wheels.
Inner races are precision-ground hardened steel to provide the correct surface finish and geometry for tapered roller bearing operation.
Manufacturer reference number 25520 allows cross-referencing with bearing suppliers for cone and race kit compatibility verification.
Backed by a limited 1-year manufacturer warranty against defects in materials and workmanship when used as intended.
During any hub service -- annual repacking or pre-season inspection -- remove the hub and visually inspect the inner race surface. Replace this part immediately if you observe any of the following:
The inner bearing race is a press fit into the hub bore. Proper installation requires driving the race squarely and fully seated using a bearing race driver or a suitable driver tube -- never use a hammer directly on the race face. An improperly seated race will cause premature failure regardless of cone condition.