These bushings are often overlooked when upgrading the suspension of a 4WD. Leaf spring bushings stabilize the movement of the rear axle, inferior bushes in this area will cause the solid rear axle to move and impart rear end passive steer to the vehicle. It also causes the vehicle to "wander" all over the road and be unstable under heavy braking. This can be especially noticeable carrying a load or towing a boat or caravan. The OE rubber style bushes are designed to work at standard height with standard tires and with standard loads. By fitting SuperPro Bushings and upgrading to Greaseable Shackles the rear end of your 4WD will handle just about anything you can throw at it!