RSO Non-Knurled Lower Ball Joints for Wrangler JK/JKU Factory Ball Joints are one of the most common wear and tear components of your suspension and can’t handle bigger wheels, increased weight or simple offroading. Vibrations, steering issues and even death wobble can be resolved by replacing worn out factory ball joints. The RSO Suspension heavy duty ball joints are manufactured from alloy steel housings using heat treated 4140 chromoly studs. Complete with heavy duty dust boots and fully serviceable with zerk grease fittings for easy maintenance these ball joints stand up through years of abuse. Heavy duty direct fit replacement manufactured from chromoly steel outperforms weak OEM ball joints Machined ball joint stud from heat treated 4140 chromoly and alloy steel housing to withstand offroad abuse Fully serviceable using heavy duty rubber dust boot and grease zerk fittings for extended life and performance Eliminates steering and suspension issues caused by worn out factory joints for a safe and comfortable ride 500 mile break-in period required for proper seating of bearing surfaces to ensure smooth long life operation