Rear Coil Spring Correction Plates | Jeep Wrangler JK/Wrangler Unlimited (07-18) Run your rear coils at the right angle; these shims correct the rear coil angle of a lifted JK by 10 degrees, thus putting them at the optimum angle for on and off-road applications. A bowed coil spring can rub against the track-bar bracket or other components. Utilizing a correction shim keeps the coil straight, thus prolonging the life of the coil itself as well as giving a more pleasurable driving experience. Rough Country now offers these shims pre-included in the popular Jeep JK 3.5in, 4in, 4in X-Series, and 6in X-series kits. These correction shims may also be purchased separately, and are easy to install on existing equipment. 1113