Many owners of the four-door Jeep JK Unlimited are discovering that the vehicle is capable of more than just picking up groceries and taking the kids to school. The Unlimited has proven itself as a true trail-ready vehicle and is just as at home on a rocky ledge as it is in a Wal-Mart parking lot.
When JK owners are ready to go to the next level, the vehicle can also become a serious rockcrawler with some modifications to the suspension. Most short-arm kits for this vehicle offer improved ride height and travel, but the JK's weak points are its front and rear driveshafts, as well as its longer wheelbase that adds additional leverage and stress to the control-arm joints. For this reason, many aftermarket suspension kits limit the JK's lift height to 3 inches. When we saw that Trail Master designed a 5-inch lift kit for the JK, it caught our attention.
The Jeep Unlimited four-door...
The Jeep Unlimited four-door can handle its own on the trail, but for more serious adventures, it needs some added suspension travel and larger tires. Enter Trail Master's 5-inch Flex-Joint suspension system. Trail Master provides everything in the kit, including new Kevlar-lined brake lines, shocks, and heavy-duty front and rear driveshafts.
Trail Master's 5-inch Flex-Joint suspension solves all of the problems associated with adding a greater amount of ride height to the Jeep JK. Aside from allowing the use of 37-inch-tall tires for maximum ground clearance and traction, the suspension system gives the JK much better trail performance by improving articulation and suspension travel.
Trail Master uses a unique rod end in the company's control arms called a Flex-Joint. Flex-Joints replace the standard urethane bushings that connect the control arms to the frame where added stress typically damages the bushings over time. According to Trail Master, the Flex-Joint material is as hard as steel yet forgiving enough to allow full articulation without excessive wear.
Five inches of ride height also adds some serious pinion angles to the factory driveline. In order to avoid premature wear of the Jeep's dual driveshafts, Trail Master decided to replace them by including heavy-duty units with its system. If you've already replaced your JK's driveshafts with sturdier units, the kit is also available without them.