550 lb. Capacity Non-Adjustable Torsion Half Axles (5-4.5" Bolt Circle) Torsion Half Axles with Flexiride Rubber Bushings that eliminate the need for trailer springs. 550 lb Capacity Non-Adjustable spindle, Welded into position 6 Mounting holes 5-hole, 4.5" bolt circle (2 3/8" center stud to center stud)