Is 7.5mpg Worth It to Run 37s on Your 4Runner and Become a Rockcrawling Beast?

Josh’s 4Runner at @feralpigrig proves that sometimes the most capable rigs come from the most unexpected packages. Starting life as a ‘15 Limited - you know, the soccer mom spec with heated and cooled leather seats - this machine has been transformed into an absolute IFS flexing monster that’ll make solid axle guys question their life choices.

The heart of this build revolves around a +2 long travel setup that completely changes how this IFS 4Runner behaves on the rocks. We’re talking about a system that allows those massive 37x13.50 Maxxis tires on Method beadlocks to articulate in ways that’ll make your jaw drop. Josh recently proved this wasn’t just for show when he took first place in the IFS class at an RTI competition, also beating out several solid axle rigs in the process. That’s the kind of performance that makes you rethink what’s possible with independent front suspension.

Fitting 37s on a 4Runner isn’t exactly a bolt-on affair. Josh and his crew had to get creative with the body work, trimming fenders, hammering firewall sections, and completely removing wheel well liners. The front bumper got trimmed, pinch welds got persuaded with hammers, and the whole setup required some serious supporting modifications. We’re talking CVJ axles, tie rod extensions with collars for strength, Apache off-road body mount relocates, and 4.88 gears to keep those massive meats spinning.

The suspension setup deserves its own spotlight. Fox shocks up front handle the long travel duties, while Dobinson MRR components out back provide the flex that makes this thing look like it’s doing yoga on the rocks. Without sway bars front or rear, this 4Runner can twist and contort through terrain that would leave stock rigs high and centered. Add in the KDSS track bar correction kit, and you’ve got a rig that won’t try to kill you on the highway between trail runs.

Triple locked with ARB air lockers front and rear (and the factory center diff lock), this Limited has the traction to back up all that articulation. The dual air compressor setup feeds the lockers and provides onboard air for trail repairs and airing down those wide 37s. Speaking of airing down, the Vlocks off-road Go Wings on the rear windows keep all the deflation gear organized and accessible.

The Windworks dual swing-out carrier deserves special mention for its engineering. With the crossmember cut for clearance, this setup provides massive departure angles while still carrying a full-size spare, MaxTrax, shovel, and jerry cans. The clearance gained here is immediately obvious when you see this thing backing up to obstacles that would catch most rear-mounted spare setups.

Josh hasn’t forgotten the practical side of wheeling either. An iCamper BDV Duo sits up top with matching solar panels feeding an EcoFlow power station. The ICECo fridge slides on L-tracks in the third-row delete area, and the whole electrical system runs off a single Interstate AGM battery for now, though dual battery upgrades are on the consideration list.

The lighting package reads like a Baja Designs catalog - 30" light bar up front, fogs, ditch lights, chasers out back, S2 rock lights, and S1 wheel well lighting. Everything runs amber for that proper desert racing aesthetic, and the Meso Customs wiring keeps it all organized and functional.

A Mishimoto transmission cooler and power steering cooler handle the extra heat from pushing 37s through technical terrain. The ARB snorkel with cyclone pre-cleaner keeps the intake happy in dusty conditions, while diff breathers ensure the lockers don’t get contaminated during water crossings.

The fuel economy question always comes up with builds like this, and Josh is refreshingly honest about the 7.5 MPG reality. But when you’re piloting something this capable, the pump pain becomes secondary to the performance gain. This isn’t a daily driver build - it’s a purpose-built trail weapon that happens to retain creature comforts like those heated seats and Alpine head unit.

Check out more of Josh’s adventures and build details on his Instagram @feralpigrig, and if you’re considering your own long travel conversion, this build shows exactly what’s possible when you commit to doing it right. Sometimes the most capable rigs come from the most unexpected starting points.