This 1,500lb capacity Galvanized Boat Trailer Axle is designed to fit a 46inch wide I-Beam Trailer. The Hub Face (Track Measurement) on this Torsion Axle Measures 53 inches. It comes equipped with Galvanized 5 Lug Idler Hubs and features a greasable spindle, along with the standard 1.98 inch Accu-Lube Style Dust Cap so you can easily add grease to the Bearings for maintenance. It also features a 2 Hole Brake Flange for installing Trailer Disc Brakes, and measures 46 inches from Brake Flange to Brake Flange, and 46 inches to the Outside of the Torsion Mounting Bracket. The Starting Angle of this Torsion Style Boat and Jetski Trailer Axle is 30 Degrees Down. Torsion Bar Axles are perfect for Salt Water Jetski Trailers because they last longer than Leaf Springs, which tend to rust quickly. The hubs are included pre-installed on this Torsion Axle. The Trailer Hubs use standard 44649 Bearings (1 1/6" inner diameter) for both the outer and inner bearings. The Seal Size for this galvanized hub is 1.25 inches inner diameter. The Boat Trailer Hub uses the standard size lug nuts for trailer hubs and wheels, ½”x20, and the bolt pattern measures 4.5 inches. The axle/hub does not include brakes, but there is a 2 hole brake flange (2 7/8 inches center to center) on the Torsion Arm so you can mount disc brakes to it, or swap out the hub to drum if you prefer. This Model Torsion Axle typically would use 4.80 x 12, 5.30 x 12, or ST145 R12 Trailer Tires depending upon the trailer. However, this jet ski torsion axle sku is not compatible with 18x8.5x8 or 20.5x8x10 trailer tire and wheel sizes. This pre-installed hub is already greased with a Lithium Based Grease. Additional Lithium Grease may be applied before use.