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Fitting 54-Inch Tires on a 1993 Ford F-350

Posted in Project Vehicles on August 4, 2016
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Crewferd was for sale. Crewferd is a 1993 Ford F-350 work truck I bought off of for last year’s Cheap Truck Challenge, but it became a bigger project then I had hoped it would be. I had to fix the engine, then I regeared it, locked it, and bolted on bigger tires (37s). It was a cool-looking truck, but with only a small-block Ford 351 V-8 and a C6 three-speed transmission it wasn’t going to win any races. It was just fine and ready for a new owner, but no one called. And so it sat in my front yard waiting.

Then I decided to build it again, but this time for an episode of Dirt Every Day, the online video show I host in addition to my magazine job. I decided to see if we could swap giant 54-inch Mickey Thompson tires onto Crewferd and take it wheeling. The goal was a fullsize on massive tires built in under a week and taken to Johnson Valley for a rockcrawling trail. What we did worked, but I’d be lying if I didn’t admit to cutting some corners for the sake of video action and production timing.

The big truck is even bigger now, and although it works well I wanted to touch on the upgrades I’d recommend for even more reliable performance. Consider this a behind-the-scenes look at a quick video build with suggestions on how I’d rather see it done. Do as I say, not as I do.

The 54-inch Mickey Thompson Baja Claws TTC are massive, heavy, 19.5/54-20LT bias-ply tires and require a 20-inch wheel. I opted for a set of 20x12 Dick Cepek DC-2 Black wheels, but I would really suggest a beadlock for the ability to air down further. The Dick Cepek wheels are nice and strong—almost too nice to destroy on rocks.
I put new 4.10s and Detroit Lockers in the Dana 60 front and Sterling 10 1/4 rear for the 37s. Ideally, gearing for the 54s should be 7.17:1 but going any lower on a Dana 60 requires a carrier change so I stuck with my 4.10s. I also kept the 30-spline front stub shafts and factory selectable hubs, which was another bad idea that I don’t recommend, but somehow they lived. I’d rather see and upgrade to 35-spline stubs and premium Warn or Dynatrac hubs or drive flanges. To cap the axle ends, we added dualie hubs from a Dana 60 that helped clear the big tires by pushing them outwards a fair bit. This worked great but added tremendous leverage to front axle wheel bearings. I think the best bet for 54-inch tires would be 2 1/2-ton or bigger axles, but somehow our 1-tons survived.
To clear the big 54s, I called up Skyjacker for a 6-inch lift. This worked great and is one component I wouldn’t change. Even with the 6-inch lift we had to do tons of body trimming, beating back the firewall, and cutting the bed completely open. And still the tires rub a little bit at full compression. But overall this was a win. With such big tires I’d look into a traction bar to defend against axlewrap from the leverage of big tires.
Because of the lack of gearing in the axles I went with additional transfer case gearing in the form of an Offroad Design 203/205 Doubler I bought used. This was a lifesaver. I engaged the front NP203 reduction box and never disengaged it. This made up for our lack of low axle gearing on the road, but I still wish we had lower axle gears to spin the massive rubber. From the transfer cases we ran a set of JE Reel driveshafts. These were ordered and showed up days later perfect and vibration-free.
Turning big tires on the trail isn’t easy, so I went with a PSC full-hydro power steering system. This was another win—if I had built a beefy tie rod. The PSC pump replaces the whining Ford pump and the orbital valve and single-ended ram make steering easy. But the stock tie rod isn’t up to big tires and full-hydro strength. It needs a massive tie rod to push those tires around. The stock one worked, but you could see it flexing at every turn.
The cooling system in the Ford needs work but survived. The radiator needs a fan shroud, the C6 automatic transmission needs a big beefy cooler, and the power steering needs its own separate cooler. The Ford ran but got hot playing in the sand and climbing big Johnson Valley rocks, so this is also on the “to be upgraded” list.
I was going to build rock sliders. I should have built rock sliders. Now Crewferd has a smashed door and bed. Do yourself a favor and build rock sliders before you hit the dirt.
So now what? I could fix all this stuff, add a bigger engine, and have a big bad monster rockcrawling fullsize. Or I could put it up for sale and let the next guy finish the project. Or I could drive it as it is and see what breaks or burns up first. It drives pretty bad on the road but is fun to wheel around on big open trails. Either way I hope you learn from what I did that cutting corners works sometimes, but when it doesn’t you may end up stranded on a trail with a massive broken 4x4.


Huntington Beach, CA 92647
Skyjacker Suspensions
West Monroe, LA 71294
Offroad Design
Dick Cepek Tires & Wheels
Stow, OH 44224
Warn Industries
Clackamas, OR 97015
Mickey Thompson Performance Tires & Wheels
Stow, OH 44224
PSC Steering
JE Reel Driveline Specialists
Eaton Corp./Detroit Locker

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