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Custom 2015 Jeep Wrangler Rubicon JKU

By Dan Everett | Photos by Cristian Brunelli, 30 Jul 2017 Custom 4x4s

Custom 2015 Jeep Wrangler Rubicon JKU 1

Trail-jumping JKU Wrangler Rubicon proves that orange is the new black.

FOUR-WHEEL drives are all somewhat versatile, but they still tend to fall into certain niches depending on the gear you fit to them. Want to travel to the ends of the earth and back? A two-inch lift and some 32s will be bang on for that job. Aiming to take on the toughest tracks you can point your winch at? How about a set of 37s and enough lift to see you looking down on yank-tanks like they’re city runabouts?

Vote for the 2015 Jeep Wrangler Rubicon JKU to win 2017 Custom 4x4 of the Year

In a dream world we’d all have Jay Leno-style garages with a different 4x4 for every day of the week. After all, you’re not going to punt a stock Navara through six stages without days of winching, and you’re not weaving your way through Cape York looking for remote campsites with an 8in-lifted Patrol. So, what’s a man to do when he wants it all? Well, if you’re anything like Bill, you buy a Jeep.

If you’ve had your head in the sand (or up a suitably dark orifice) you mightn’t have noticed how incredibly popular Jeep’s four-door JK is. Put simply, they’re one of the most popular 4x4s on the tracks right now, and it’s down to their sheer versatility.

“I’ve had a few different 4x4s, from stock to highly modified,” Bill told us. “But I wanted something that could do all of it. The only option was a Rubicon.”

Off the showroom floor, the Rubicon picks up a beefier front axle than the Sport model, as well as lower transfer case gearing and a heap of trick off-road gear like rock sliders and electronically disconnecting swaybars. While some might be happy with a spec sheet like that, Bill figured he could do better and had the guys from Double Black Offroad (DBOR) go right through the Jeep from front to back before the dealer had even screwed the plates on.

Video: Watch us have fun in this rough-and-ready JK Rubicon!

Alright Jeep fans, we know you want to hear more about trick suspension and over-sized wheels than custom bonnets and unique paint jobs, so we won’t waste any time. Bill’s JKU is now sitting 4.5in closer to the skies thanks to a full DBOR Wild Kit. Despite the Rubicon sporting the far superior D44 front axle, the suspension links lack the adjustability to run at taller lifts and can easily turn into pretzels in hardcore wheeling situations. To rectify this, the DBOR Wild Kit swapped out all the factory offerings and replaced them with heavy duty adjustable items from US-based Synergy Manufacturing.

Of course, arms alone aren’t enough to get the clearance required, so the box was also ticked for a taller set of coils front and rear thanks to the guys at Rubicon Express. Those with eagle eyes will spot both front and rear axles are kept in check with Fox remote reservoir 2.0 shocks, the external reservoir allowing for more oil volume to help fight shock fade. The kit also comes with a heap of hard parts to make things work like stock, such as longer brake lines, extended bump stops, and relocation brackets to get the front and rear Panhard rods sitting flatter for a more compliant and predictable ride. The factory Rubicon front and rear diff locks have proved they’re more than up to the job, although Bill uses a Superchips Flashcal to disconnect the swaybars and engage the lockers in high-range.

Readers' 4X4s: Wrangler JKU, GU Patrol, Defender 130

Where most 4x4s have tyre sizes limited by the wheel arches, Bill was able to swap his low-hanging units out for a set of DBOR’s Flatty Fenders. The new fenders, combined with the suspension kit, lets the big JK swallow the huge 37in BFG KM2 tyres, with Walker Evans beadlock wheels keeping them in place even when pressures are dropped down to single digits.

Got your fix Jeep freaks? Now back to your regular programming. The front of the JK sports a more aggressive look thanks to a stubby DBOR bullbar. It not only provides a better approach angle for technical rock driving but also houses a fully waterproof Smittybilt X20 12,000lb winch. Lightforce’s HID/LED combo HTX230 driving lights also made it on there, with a set of LED headlights replacing the stock 7in candlesticks in the M1 mesh grille. While Smittybilt boast features like stainless construction, Bill just wanted to stand out in a crowd of angry eyes.

LED lights rubicon JKU
To help the Jeep cope with Australian conditions, a Daystar hood cowl was installed with a set of their bonnet vents and an AEV snorkel feeding into the Air Raid air box. Daystar claims the set-up can reduce under-bonnet temperatures by as much as 12 per cent, which should give Bill confidence for slow-wheeling in the summer months.

In the three days a year the sun comes out in Victoria, the stock removable hard-top gets yanked off with a roof-winch set-up, with a Smittybilt mesh roof and cargo net helping keep Bill’s gear in and the sun out. The rear end copped similar treatment to the front, with an Atlas rear bar getting the heavy 37in spare off the tailgate and onto a dedicated carrier. The set-up not only gets the load off the tailgate hinges but also provides vital protection for the exposed rear quarter panels, and it also sees the rear kitted with twin recovery points and 40 litres of fuel storage in twin Jerry cans.

Video: Custom 2014 Jeep JKU Wrangler Rubicon Unlimited

Like the rest of Bill’s Jeep, the interior came together like a man-sized Meccano set, with key upgrades exactly where he needed them.

“I’ve owned an old FJ40 before,” he told us. “So I know how much vinyl and leather burn after sitting in the sun for a while, and opted for the cloth Rubicon seats instead of the leather option.”

rubicon jku interior
A GME UHF has also been fitted up for convoy comms with a matching aerial up front on the DBOR bullbar, while Jeep rubber floor mats help keep mud off the carpet. Navigation off-road is handled by the factory in-dash head unit, but Bill’s ran through the stereo system and upgraded components left, right and centre to build the ultimate summer cruiser.

It's near impossible to build the perfect do-it-all 4x4, but while manufacturers are offering easily upgradable platforms and the aftermarket are finding smarter ways of making use of them, we’re getting closer and closer. Bill’s JK Rubicon has all the gear to take on some of the toughest tracks, and it can lift huge 37in tyres a metre in the air and still remain composed. At the end of that he can hose it off and drive to the other side of the country. It really is proof that the actual modifications you make to a 4x4 don’t impact reliability, it’s how well they’re done that’ll give you the results you’re looking for.


We mentioned before that Bill’s Rubicon comes optioned up with the beefier D44 axle rather than the base model’s D30, but if you’re not fluent in seven-slot grilles, that might not make a whole lot of sense. Unlike most other 4x4s that use their own proprietary axle assemblies front and rear, Jeep diffs are from aftermarket manufacturer Dana – yes, the same Dana offering rear axle upgrades for Land Cruisers.

hill climb custom rubicon jku
In JK Wranglers, you’ve got the choice of either a Dana 30 front axle or Dana 44, depending on which spec you get. There are a few key differences that make the D44 axle the pick of the two, such as an increased spline count on the axles (30v32), a sturdier gear carrier which can prevent deflection and damage to the gear set under load, and a physically larger ring and pinion. While the differences aren’t huge, they do mean the larger axle will cop more punishment from larger tyres without too much concern.

If you’re looking to kick things up a notch, the Dana 60 axles, which are beefier in every single way, are the next step up the ladder and are a key component to getting a late-model Jeep road legal on 37s.