New for 2017. The X4, X6, & X7 Hyper left rear torsion arms are now designed with two shock mounting holes. The idea for the new hole, which is closer to the shackle mounting hole, was conceived when the R&D was being performed for the X7 chassis. More shock control was needed to control the rear axle when in the forward position (short wheel base). In lieu of re-valving our shocks, we just added the new hole which adds 10% more effective shock rate to the dampening system thanks to the mechanical advantage change. We did the same for the right rear torsion arm 40-1725.
The new arm is also made a little stronger by increasing the relief pocket radius and increasing the web thickness in key areas.
Machined from 2024 aluminum for superior strength. Rear torsion arms are measured from the center of the splined torsion bar hole to the center of the shackle mount hole. Squeeze bolt kit is included. Send us your old torsion arms or a sketch, and we will offset torsion arms to your specifications at no charge.