Fabtech 17-21 Ford F250/350 4WD Floating Rear Traction Bar System2017 20 Ford F250 F350 4WD. Reduce rear leaf spring axle wrap caused by tall lift blocks, heavy torque engines and oversized tires with Fabtech's heavy duty Traction Bars. These Traction Bars utilize a shackle design on one end to allow movement with the arch of the leaf spring travel. This provides a non binding, smooth highway ride yet still provides positive resistance to torque loads. These floating style Traction Bars are a bolt on design for