38’s and No Lift on a 2024 Jeep Wrangler Rubicon 392
Big tires and a low lift height have traditionally been a recipe for success when building an off-road vehicle to tackle more extreme terrain. While there are plenty of challenges to overcome with this build philosophy, keeping the center of gravity low equates to better stability on-road and off. Without question, there is no other vehicle easier to do this with than the Jeep Wrangler. This is especially true for the Wrangler Rubicon 392 as it comes with highline fenders and two-inch lift springs direct from the factory.
In the past, we’ve shown you how easy it is to run a 37-inch-tall tire on the Jeep Wrangler Rubicon 392 without changing the suspension height. However, we wanted to push the limits even further and see if we could squeeze on one of the most popular 38-inch-tall tires on the market, the Nitto Trail Grappler, under our 2024 Jeep Wrangler Rubicon 392. While you can clearly see that we accomplished our goal of putting the tires on, the real question is, was this truly a functional upgrade?
The Tire
We’ve had excellent luck with the Nitto Trail Grappler in the past. With the 38x13.50R17 version weighing in only three pounds more than a 37x12.50R17 Trail Grappler, this true-to-size mud-terrain radial is an ideal pick for those in the market for a 38. In our experience, it rolls smoothly, works unbelievably well off-road, and has a logic-defying tread pattern that while incredibly aggressive, somehow remains quiet on the highway. It’s basically a magic tire.
The Wheel
While the 392’s 17-inch wheels are beadlock capable, we needed to move to a wheel with different backspacing as the stock 5.2 inches of backspacing the Wrangler came with would create rubbing issues. Ultimately, we landed on a 17x9 KMC Tank beadlock in the version offered with 4.4 inches of backspacing. Aside from the looks of the wheel, we liked that these beadlocks have drain windows for water and debris to easily escape.
Spare Tire
The tire and wheel package comes in around 120 pounds, which is fairly normal for this type of combo. With the Wrangler 392 coming from the factory with the Mopar tailgate reinforcement and spare tire relocation bracket, we were able to shoehorn the spare on the back. Yes, it does contact the bumper slightly, but not enough to be concerned with. To make the third brake light more visible, we simply moved it up one bolt hole on the original light bracket. The biggest issue with the spare is that the tailgate isolators no longer contact the backside of the tire. This will be something that we will need to address.
Rear Panel Removal
We got our new tires and wheels through our local off-road shop, Low Range 4x4. Before we left the shop, we removed the three 8mm bolts securing the plastic inner liner located at the bottom of the rear flare. We’ve rubbed this in the past with a 37 and knew this would be an issue with a 38 at this height.
Front Bump Stops
Something unique to the Wrangler 392 is that the front bump stop towers are two inches longer than what you would find on a standard Rubicon. While this works fine for limiting the travel of a 37-inch-tall tire, for a 38, we added 1-inch of additional bump via these stackable pads we had left over from a JKS suspension kit.
Rear Bump Stops
The 2024 Wrangler Rubicon 392 comes with 1-inch rear bump stop landing pads, which we swapped out for these stackable ones from JKS. This provides 2.5 inches of total bump stop spacing.
On-Road Driving
With nearly 500 horsepower on tap and 4.56 differential gears, moving to a 38 isn’t as drastic of a performance impact as you might think. While we did loose 1-inch of up travel in the front and 1.5 inches out back, we gained a massive tire. This added rubber helps absorb road imperfections and equates to a mostly unchanged ride dynamic on the street. In terms of rubbing, we haven’t experienced any on the road, even with spirited speed hump engagement. The biggest complaint we have is that the steering is noticeably heavier.
Off-road
The real test for this setup is would it work off-road. Before we hit any sort of challenging mountain trail, we needed to see what would happen once the sway bar was disconnected and Jeep twisted up. For this, we hit the beach during low tide so we could max out the suspension travel using a few sandy drop offs. With the tires dropped to 12 psi front and 10 psi rear, we confirmed what we had suspected. The rear clears fine, but the front rubs on the inner fender and the front portion of the rock slider.
Contact Patch
The rubbing on the front inner fender wasn’t enough to concern us, though it could deform the plastic over time. The real issue is with the slider contact. That could in fact damage the tire. Since increasing the bump stop height up front would further cut down on the already limited up travel, the better solution would be to get a set of aftermarket control arms and push the front axle forward slightly. Aftermarket control arms would also help dial in the caster, so the steering wouldn’t feel as heavy.
Does It Really Work?
Technically, you can run this configuration without issue on-road. However, if you are going to do any serious off-roading, the slider contact is going to be an issue. While we love the look, the limited suspension travel and contact issues makes us caution against replicating this setup as we have. An aftermarket suspension system will remedy the majority of our issues. So, that’s most likely the next step for this Jeep. If you want to check out this Jeep in action and stay in the loop for future upgrades, be sure to subscribe to our YouTube channel if you haven’t already.
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