To lift the rear and keep axlehop (also called wheelhop) under control, Rick used traction-lift bars. These are bars that bolt between the axlehousing and the springs and then continue 12 to 20 inches toward the front of the vehicle. At the end of each bar, there is a bracket that extends upward and sandwiches the leaf-spring pack. Axlehop is caused when the axlehousing tries to rotate as a reaction to the power being delivered through the axles to the tires. The pinion tries to rise in the chassis, but the springs fight this. Also, the U-joint will try to make the pinion line up with the driveshaft. The more the axlehousing rotates, the more violent the hop. Traction-lift bars have adjustable crossbars that allow you to limit the amount that the axlehousing can rotate. If the pinion rises too much, the lower crossbar contacts the spring and stops the axlehousing rotation. The upper crossbar keeps the pinion from falling too much. While these do diminish--and in some cases cure--wheelhop, they also limit suspension travel. For a dune runner like Rick's Blazer, that's not a problem, but the bars probably aren't the best solution for a rockcrawling truck that suffers from wheelhop.