Ball joints don’t last long under our Jeeps thanks to bigger tires and off-road abuse. The factory-spec joints “feature” a nylon liner that dies with the first hint of dirt or abuse. These Synergy joints feature a sintered metal bearing race instead of the nylon and also have a larger-than-stock ball. Both features allow it to take more abuse. Also, the seal is made from wear-and-tear resistant polyurethane and is held in place by a stainless steel spring seal retainer, plus the lower ball joint is greasable, unlike any other factory-spec one we’ve seen. All told, these ball joints should last us much longer than any other one we’ve run in this Jeep before.