As mentioned in Curb Weight I’m planning to use a 2022 Wrangler JL Rubicon 2 Door as my base vehicle. Without going into a lot of detail about its characteristics, it is probably the most capable off-road vehicle available off the showroom floor in Australia. So there isn’t much development required to get it prepared for overland expedition use. In fact many sources suggest that the majority of failure in overland vehicles comes from owner installed after-market options, so to minimise the expense and effort I’ll only be changing what is necessary.
Reverting Australian “Nerfs”
To comply with Australian regulations Jeep have made a few Nerfs to the Australian Rubicon specifications. These include fitting “low-rider” front fenders, and most importantly fitting very small tires (equivalent to those delivered on the Sport and Sahara models). There are a few other shortcuts that need to be remedied too.
The Wrangler JL Rubicon was developed to support 35″ tires, and is delivered in the USA with 33″ LT285/70R17 tires. Yet in Australia it is delivered with LT255/75R17 tires. This directly costs 20mm of ground clearance (under the differentials), and affects entry, exit, and break-over angles.
So we’ll specify a new tire closer to the OEM specification, but more appropriate for overlanding, with the following characteristics.
- Rugged Terrain (All Terrain) tire
- Light Truck (LT) load specification
- 3 ply side wall
- 3PMS Severe Weather Rating
- 2:1 tire to wheel diameter ratio
- Not wider than 10″ (255mm) – minimise mud throw – reduce rolling resistance – not attract Police attention
- Reputable manufacturer
Based on the above specification the best (and only) option is the Mickey Thompson Baja Boss A/T in LT255/85R17. Since the diameter of these tires is around 35 inches it is likely that the OEM suspension on the Rubicon will need extended bump stops to prevent rubbing. Fortunately Teraflex produces a bump-stop extension kit which will reduce the upward travel by just over 1″, which is enough to prevent rubbing.
Steering Damper Nerf
When converting the Wrangler JL to Right Hand Drive Jeep placed the steering damper under the track bar (panhard rod), causing it to be a full 50mm under the lowest point of the suspension. Owners who take their Wranglers off-road always damage the steering damper and can get hooked up on the large attachment point hanging under the front axle.
The recommendation is to use a Teraflex steering damper relocation kit to move the damper above the drag link and out of the way of harm. Together with the relocation kit it is necessary to add an aftermarket steering damper. The brand doesn’t matter too much but for the record, I used an ORV Rugged Ridge steering damper originally for a JK Wrangler.
After relocating the steering damper, the large mounting point hanging under the axle can be cut off with an angle grinder / cutter. With a fairly neat set of cuts about 2kg of metal comes off the front axle which helps with reducing unsprung weight.
Rubicon Lift Caster Reset
The Wrangler JL Rubicon is lifted by over 1″ over its sister models. This provides the space for larger tire sizes, but in doing the lift Jeep did not rework the control arms to retain the designed caster.
Specifically the JL Sport and many other cars use over 6 degrees of caster to stabilise the steering. Caster also has the positive side effect of improving cornering by increasing the steering angle of the tires. However, after the OEM JL Rubicon lift is fitted the resulting caster is only about 4.5 degrees.
Fortunately Mopar produces an extended front lower control arm which is 1/4″ (6mm) longer than the standard length lower control arm. This was produced as part of its Mopar 2″ lift kit. Fitting the extended lower control arm returns the front caster to 5.5 degrees. This quietens the steering and makes the driving experience much more relaxed one one finger steering.
Noted above are the extended front lower control arms and the extended bump stops, so the only additional improvement is the addition of heavy duty shock absorbers (dampers). The majority of protection required will be on corrugated roads, where the suspension travel is minimal and high frequency. This means that external reservoir dampers, which are designed for long travel situations (like a Baha race) are not the best solution. For the Australian outback I have selected to use the Ironman 4×4 Foam Cell Pro dampers. These dampers are traditional double action (not pressurised), with huge oil reserves and very solid (rebuildable) construction. It is also worth noting that they extend the axle droop by over 2″ over the standard dampers, as they are specified for a 2″ lift kit. The extended droop makes the front axle more compliant to the terrain, and more than compensates for the reduction in upward travel through the extended bump stops.
As the ball weight of my trailer combined with the load of equipment will add about 240kg to the rear of the vehicle, it is necessary lift the rear when fully loaded and yet allow the full travel and comfort when the vehicle is used for rock crawling day trips. The ideal solution for this is to use Air Bag suspension assistance, which allows adjustable support up to 400kg. I’ve fitted AirBag Man Heavy Duty airbags.
The Wrangler Rubicon has a very light weight plastic rear bumper bar. The OEM tow bar is fitted underneath the bumper on a chassis cross member with 4 high tensile steel bolts. The rear recovery hook is bolted to the chassis with 2 high tensile bolts.
To provide a solid towing and recovery platform the rear bumper and hook were removed and a Smittybilt XRC Gen 2 rear bar was fitted. This bar is bolted to the chassis with 12 high tensile steel bolts, 4 in the normal OEM tow bar location, and 4 at each chassis rail. The bar itself weighs over 53kg, and provides a Class 3 Receiver and two recovery and high lift jack points.
Removing the OEM rear bumper necessitates relocating the number plate. The relocation was done with a combination of the included Smittybilt product and an ARB number plate relocation kit.
Trailer wiring for Australian (APAC) vehicles is different to the American (NAFTA) solution. The NAFTA Jeeps do not have a separate brake and indicator system; their brake light is flashed as an indicator. So purchasing a NAFTA Trailer Wiring System is not going to work. The best solution is the purchase the Australian (APAC) Trailer Hitch kit (MOPAR Part Number LA82210162) directly from a dealer. The Australian Trailer Hitch kit includes a 2″ drop tongue, 50mm ball and Australian 7 Pin Flat Trailer Connector, as well as an OEM hitch point (which I have not used).
The international Trailer Brake Controller (MOPAR Part Number 82215652AD) kit works well with the Australian Trailer Hitch kit. The control knob fits nicely into the dash, replacing the 12V cigarette plug, and the ECU can be stuffed up into the space behind the panel in the passenger footwell.
Fitting the Australian Hitch kit meant passing the trailer wiring INSIDE the vehicle (like the Quadratech video) not outside according to the instructions and joining the wiring in the LHS (passenger) footwell with the Trailer Brake Controller.
The accessory wiring and Trailer Brake signal wire are both found in the LHS footwell. From the LHS footwell the power supply for trailer lighting and trailer brake can be (optionally joined to one supply and) passed through the firewall into the LHS front wheel well and so to the battery.
Other Things Worth Mentioning
Added a K&N air box and filter kit, and integrated the OEM cold air intake into the bottom of the K&N air box.
A Taser JL Mini allows the tire size and many other settings to be done at any time. It also provides live info on the manifold vacuum and does light shows when needed.
I’ve added a GME UHF radio in the centre console, connected to a 2.1dB Rubber Ducky antenna on the tail-gate. There is a Teraflex tail-gate mount for both antenna and sand flag.
Also on the tail-gate there is a Rockslide Engineering table, and some additional 12V connectors and USB power supplies powered by the Renogy Lithium battery along with a Renogy 240V 2kW inverter system.
I’ve removed the small 12V Accessory Battery (saving over 5kg), and all associated wiring, leaving just the Auto-Start relay in place to ensure there are no ECU codes generated. Bridging N1 and N2 in the power distribution centre ensures that normal service for all power systems is retained, even the Auto-Start function.
An ARB air compressor is fitted in the engine bay with a RHD specific mount from TLR.