Spidertrax Ultimate 40 spline Inner Axle Shaft Assembly - Single 6-38 (Sa/Sb are Measured in Inches from Center of U-Joint to End of Shaft)  Spline Detail: 40 Spline Inner Axle Shaft 24/48 Pitch 45 Pressure Angle Class 6/7 Fillet Root Side Fit 

The SPIDERTRAX AXLUSD40M1 is an Ultimate Inner Shaft, 40 Spline, 6-3/8 inches long. Engineered to complement Ultimate U-Joints and Ultimate Stub Shafts for off-road performance, this axle shaft features a webbed yoke design allowing for 50 degrees of steering angle, the industry's tightest for a 1480 60-style u-joint. Both the axle shaft and yoke are constructed from billet domestic 300M military-grade steel and undergo AMS2759 aerospace-level heat treatment, including double tempering, snap tempering, and cryogenic treatment. The 40-spline design allows for precise fine-tuning of shaft diameter for optimal torsion and strength. The 300M yoke has extended shaft engagement in length and diameter, and a larger yoke OD for increased strength at high steer angles. Manufactured, heat-treated, and tolerance-verified in Colorado, USA. Sold individually. Custom-made with varying lead times and non-refundable.