Currie’s Rock-Jock JK track bar is made from 4130 chromoly steel tubing, with a 11⁄4-inch diameter and a 1⁄4-inch wall thickness. This is far stronger but lighter than the stock JK bar. It’s also adjustable for different heights of lift, and greaseable. The close-ups show the major difference between the worn stock rubber bushing and the special skinny Johnny Joint.