JOES JR Sprint Splined Axle is stronger, lighter, and more adjustable compared to our previous steel axle. It is 1-1/2" diameter with 23 splines on both ends and a keyed rotor carrier. We managed to take off over 2 pounds of rotating and unsprung weight while increasing the strength at the same time by using 7075-T6 material. The splines and threaded ends let you move your wheels in and out just like they do on bigger cars. All the components needed for a complete rear axle assembly.