One drawback to using leaf-spring suspension is rear axle wrap. This is most prevalent in rigs with soft springs and spring-over axle arrangements. Axle wrap is an effect that occurs upon rapid acceleration. The axle rotates and changes the rear pinion angle, which can cause the driveline to bind and possibly break. One way to control axle wrap is through the use of an anti-wrap bar or ladder bar. The anti-wrap bar shown is fixed to the axle but is allowed to pivot on a shackle and bushing to permit suspension compression and extension.