This Replacement Bearing and Bearing Race kit for 3,500lb Capacity Axles includes contains the required components to replace your 1,750lb Hubs races, bearings, and grease seal. The components inside this kit are referred to by many names at times. Typically the trailer bearings are always called bearings. However, the bearing races can be referred to as bearing cones, or bearing cups. Either way, the Bearing races are usually pre-stamped inside the hub, so the first time you will be working with them will be the first time you re-pack your trailers Hub Bearings. The standard 3,500lb capacity axle contains two hubs, each with a capacity of 1,750lbs. While their are some variations and non standard trailer hubs, at kodiakTrailerBrakes.com we are dealing with more standardized parts associated with utilizing Kodiaks disc brake system. If this bearing kit does not match your arrangement, it is most likely a non-standard trailer hub.