Bigger Tires and more flexfor YJs
You've seen them on the trail: Jeep YJs with 35-inch tires flexing through extreme obstacles with ease. Or better yet, another YJ sitting on 33s completing the same obstacle without a worry. How is this possible when you can't get your rig through without dragging U-bolts across boulders or stuffing tires in fenders? It's called a spring-over-axle setup, friends, and it's just about the greatest means of increasing suspension flex and tire clearance in leaf-spring suspension systems.
Considering the benefits of a spring-over-axle suspension setup, it's not surprising that one of the most frequently asked questions we hear is: How do I go spring-over? A good deal of kits are available from the aftermarket, but there's no reason why one couldn't put together his or her own kit with off-the-shelf and used parts. Depending on the desired tire size, the stock springs may be reused and still supply a few inches of lift simply by residing atop the axle. Having the stock springs as an option also allows the owner the opportunity to lift their vehicle in stages, going bigger as needed, or as money permits. Since we were determined to run 36-inch tires, however, we chose to use a set of 2.5-inch lift springs from Deaver Spring. Along with the springs, we acquired other necessary equipment, including Rancho RS9000 shocks, limiting straps, extended bumpstops from T&J Performance, extended brake lines, new spring perches, and U-bolts. Once the new suspension was installed, we measured for new driveshafts using a CV 'shaft in the rear. We recommend a slip-yoke eliminator if one isn't already installed.
Addressing our steering needs, we decided to maintain use of the stock steering knuckle, which now situated the tie rod beneath the springs. Using a dropped pitman arm and an S-Link drag link from T&J, we nearly achieved the factory steering geometry, even with the absence of a track bar. Other steering options when completing a spring-over conversion include crossover style and high-steer designs, but since our tie rod was even with the centerline of the axle, it was far enough out of harm's way that it wouldn't create any clearance issues.
With parts in hand, we headed to T&J Performance in Orange, California, where we completed the spring-over conversion. Check out the photos for an overview of the process.