This tapered trailer roller bearing is standard bearing number 02475, measuring 1 1/4 inch inner diameter and fitting into race #02420. This is a Tapered Roller-Style Bearing, which is the most common bearing type among Trailer Hubs. This bearing is most commonly seen in axles that are 7,000-8,000 lb capacity with 8 lug hubs, where this is used as the outer bearing. This is generally going to be the smaller bearing of an 8 bolt hubs bearing combination, used in conjunction with a 25580 bearing to fit onto a tapered 1 3/4" x 1 1/4" trailer spindle. This particular Bearing is not one of the common outer bearings for heavy-duty 7k and 8k hubs, so it is always best to check your Trailer Hubs and Axle to make sure you get the proper Bearing replacement for your Boat or Utility Trailer.Bearings need regular maintenance and Periodic replacement in order to keep your trailer in safe operating order. Most of the time Bearings are replaced in pairs, along with the Trailer Grease Seal. If you are looking to replace all of your trailer bearings and the grease seals, we do sell Trailer Bearing Kits on our website which could get you all the parts you need in one simple package. Here is a link to our Bearing Kit Category.To install a Bearing into your trailer hub, you need to start by Packing the Bearing full of grease. Take a handful of Trailer Wheel Bearing Grease and press the bearing into it, rotating the bearing as you go to get grease in each of the individual rollers. Once youve completely packed the bearing, simply drop it into your trailer Hub so it sits inside the matching Race. Depending on if the Bearing is the Inner or Outer Bearing of the hub, it will be secured into place with either the Hubs Grease Seal or the Flat Washer and Locking Mechanism on your Trailer Spindle.Specifications:1 1/4" Inner DiameterFits Race 02420Tapered BearingFor 7,000lb-8,000lb Trailer AxlesTypically Used in 8 Lug hubs