Axle hop is bump steer gone mad.
Axle hop is an uncontrolled movement of the axle, usually brought about by inadequate or ‘tired’ shock absorbers trying to cope with a series of bumps or corrugations. In cases of sever axle hop, the 4WD will ‘dance’ all over the road and become uncontrollable.
Bump steer, axle hop and axle tramp can be experienced virtually any 4WD if you push hard enough on rough roads, so it’s important to know your vehicle’s degree of axle control. Driving technique – minimizing savage acceleration and braking – can reduce axle misbehavior.
Another value technique is to find the ‘sweet spot’ when running on corrugated roads – that speed which provides the best ride and good directional control.