This weld-on 3500 lb steel trailer axle spindle is sized to fit #84 bearing combination hubs and includes a 1 3/4" diameter round weld-on butt end. The steel spindle is designed to weld into axle tubing and replace a damaged or unusable spindle, or to build a straight trailer axle from scratch. This spindle accommodates a 1 1/16 inch outer bearing, 1 3/8 inch inner bearing, and has a 1.72-inch inner diameter seal surface. The spindle comes with an EZ Lube grease fitting installed, so you can simply attach a grease gun to the zerk and relubricate your hubs bearings without disassembling the hub. The attached brake flange is sized to fit standard 3,500 lb 5 lug axle disc brake kits, such as those manufactured by Deemaxx, Kodiak, or Tie Down Engineering; or 10-inch drum brake backing plates.If you need an accompanying hub for this spindle, you would need our Galvanized 3,500 lb Hub Kit, while if you plan to reuse your existing hubs you will just need a 3,500 lb Bearing Kit. This is a great product for repairing a broken spindle on an otherwise good axle or for building an axle from scratch if you have the experience to make these repairs or fabrications. This spindle is drilled for use with a Cotter Pinsand 1" Round Flat Washer.