Imagine your 4x4 equipped with larger-than-stock tires ripping across the desert or mud bog when all of a sudden a hidden berm, log, or ditch sends you skyward. You land with a crash and likely do one of two things: get out and check for damage, or spin a U-turn and do it again because it was so much fun. Either way you may want to consider just how much abuse your axles are taking.

Axle guts are not pretty. Spending the time and money to pull out your open differentials and add lower gears, stronger axleshafts, and locking diffs will never win you a trophy at the show ’n’ shine. It won’t impress the layman like shiny wheels and big tires. However, when the going gets tough, the rocks big, the mud deep, and the trail steep, you’ll be glad you invested in your axles and not your glossy paint and loud radio.

If you’re new to four-wheeling then you’ve probably heard about changing gears and adding lockers. If you pictured shifting your transmission with locking boxes in the bed, that is not what we are talking about. Four-wheeling gears and lockers can change your truck from zero to hero as much as suspension and tires.

Big tires are often to blame for projects that grow larger and larger over time. For example, if you’re building an old Jeep, a small Suzuki, or even a mini truck and you want big tires (35s or larger) you may soon find that you want larger axles as well. The stock parts are great to a point, but eventually the leverage of big tires, low gears, and locking differentials can take their toll on axleshafts, gears, and housings. A lot of us keep running the small parts to eke out every last bit of use, while others like to upgrade for the security of not having to wrench on the trail.

What’s the Case?
Q: I finally decided to step into the 21st century with regards to my daily commuter. As much as I love the four-door JKs, the used ones are still really pricey so I have decided on a ’99-’04 Jeep Grand Cherokee WJ. They seem to have all of the modern amenities that will keep my wife and kids happy. Plus, I can cruise the highway at modern speeds without concern and they appear to have plenty of aftermarket support.

Vroom! You’re heading down the trail.
Pop! What was that?
Sssss! Uh oh, a tire’s got a problem.

This happens every weekend on trails across America. It happens to the best of drivers and the best of tires. Nothing is perfect, so round up a tire plug kit and throw it in your 4x4.

We enjoy testing new tires. And more often than not we find ourselves putting the most aggressive and knobby mud-terrain varieties at the top of our test list. For our most recent tire review we put aside our mud-terrain bias and grabbed a hold of Falken’s WildPeak All Terrain. Falken is among the few tire companies that are virtually reinventing the traditional all-terrain. This means fitting A/Ts with larger, deeper, and more aggressive tread patterns to improve not only the tire’s looks but also its off-road prowess.

BluFerd, our ’79 Ranch Raptor (aka F-150) is a good truck, but even though it’s shod with the tough General Grabbers we’d hate to walk home from the back forty if we ever encounter a flat tire. We mounted up a fifth 35-inch Grabber on a 15x8 Mickey Thompson Sidebiter as a spare tire and in an afternoon wrangled a homebrew bedside mount for the big rubber.

The high-pinion Dana 30 and Dana 44 front axles found under the ’07-to-current Jeep Wrangler JK are a vast improvement over the low-pinion front axles of the previous generation of Wranglers. While the current Wrangler front axles are fine in stock form, when larger tires, heavy bumpers, and hardcore wheeling are put into the mix the factory front axle inherits a few problems.

Out of-the-box the ’97-’06 Jeep Wrangler TJ is an extremely well-performing off-road machine. Add a small lift, lockers, and knobby tires and it will take you far. Unfortunately, many of the open-top wheelers have a ticking time bomb of a rear axle, known as the Dana 35. In the stock configuration the 71⁄2-inch ring gear and 28-spline C-clip axleshafts on the Dana 35 are adequate at best. When you add big tires and tough terrain into the mix the light-duty diff just can’t keep up. So what’s a wheeler to do?

What you want and what you need are rarely the same. Often our eyes go for the bigger slice of cake, the higher-horsepower engine, the more extreme tire. Truth be told, most of our 4x4s live on the street, and although massive muddies may look the best and work better in the slop , when it comes to a daily driver or tow rig those tires are, as Mr. Spock would say, “simply illogical.”

One of the cheapest and simplest ways to improve your 4x4’s off-road performance is to reduce the air pressure in your tires. When you lower the pounds per square inch (psi) inside your tire, it allows the tire to flex and grip the terrain more effectively. For light-duty wheeling a traditional tire and wheel set can safely be aired down to 12-15 psi. While those air pressure numbers may seem low, on today’s Load Range D and E tires they often barley put a bulge in the tire—especially when mounted under a lightweight rig like a Jeep Wrangler. To get the most performance out of the tire while safely running extremely low air pressures, a beadlock wheel is an excellent upgrade.

If you live where there is no smog testing, this story will either bore you or humor you with all the crap we have to deal with. If you live in a smog-check state like us, all we can say is good luck, it’s a pain if you own an old truck, maybe start looking for property in one of those less stringent states.

When Hercules Tires introduced the Trail Digger M/T line it was only offered in a few sizes and only as a two-ply tire. We were pleased with the performance of the two-ply tire when we tested it back in 2007 (“Massive Mud Tire Test,” Apr. ’07) but wanted to see what the new Strong-Guard three-ply technology had to offer.

Doorless Legal?
Is it legal to remove the doors on my ’92 Jeep XJ and drive it on the street in Pennsylvania? Most of the local police don’t have a problem with it, but one in particular said I needed to contact the state department of transportation for a yea or nay. After a year of trying, I keep getting the same response: “This has been turned over to our research department, who will contact you via phone in seven days.” Of course seven days comes and goes with no answer.

Been Framed
I have owned a ’61 CJ-5 since 1993. About five years ago I rolled it and bent the frame pretty badly. The cost to straighten the frame is almost as much as getting a new one, and then I’d have a 50-year-old straightened frame. I’d rather go new. If it makes any difference, the rig will be built primarily for overlanding—my wife and I are planning a yearlong expedition around the U.S. when we retire, and I want the Jeep to be as bulletproof and self-sufficient as possible.

Modern GM trucks have just about everything a guy could ask for: a powerful V-8, plenty of payload capacity, and a ton of room for gear. There’s just one thing the General keeps overlooking: a decent ride height. It’s almost as though the Bow Tie makers think we are shrinking! Fortunately, where the factory drops off, the aftermarket picks up quickly.

No matter what vehicle you wheel, sooner or later you’re destined to come across an obstacle or situation that can, and often will, devour some seemingly bulletproof part without warning. While we spend countless hours (and dollars) attempting to build our rigs as tough as possible, the one component that is constantly under load (literally) is the tires.

If you wheel a fullsize pickup then you might think carrying a spare tire is an easy thing to do. After all, most stock trucks are equipped with a fullsize spare from the factory, right? But what do you do when your truck’s tires are much larger than the factory cleats? Sure, you have a 6-foot bed you could just toss it in, but once the tire is back there how are you going to secure it? And what about all of that valuable bed space you just lost?

We love tools. The amount of tools we use on our projects is mind-boggling. Without a doubt, some tools are way cooler than others, and those are the ones we look forward to using. Our Scratch-Built Scrambler has been a long time in the making; we started documenting it in Nov. ’09. A number of components have been prototyped and installed, only to be removed. We are continually making structural change to the body or frame, so welders and plasma cutters are always in hand. Our Jeep’s Aqualu aluminum tub has had more holes drilled in it than necessary. To fill them, we could have used a spool gun, but some of the guns are messy and make cleanup a chore.

There are many ways to round up new axles for your 4x4. They range in price from junkyard-cheap to extremely expensive. We’ve scrounged through junkyards coming up with some great finds, only to spend days cutting and grinding and then welding on new hangers and mounts. Making a junkyard or hand-me-down axle fit is sometimes more trouble than it’s worth, and a guy really can’t tell how fatigued the metal is. There’s a simple philosophy behind axle swaps and upgrades: You get what you pay for. You can either have bolt-in quality or days of hard labor with a well-used axle that might end up leaving you stranded anyway.

Nuts, I’m Confused
Don’t Rock the Block
I’m 16 years old and have a ’93 Ford F-250 with the 5.8L 351 engine. I want to lift it 4 inches, but here in West Virginia it’s illegal to use blocks in the front. I was hoping you guys had some ideas to help me out. Thanks.
AJ Glotfelty
West Virginia

The KISS philosophy (“Keep it simple, stupid”) is something every truck owner has to revert back to now and again. It’s not as though we can do anything to simplify our truck’s complex electronics or things of that nature, but we can control what modifications are placed onto our pickups. The last thing guys who use their 3⁄4-ton truck for daily driving and heavy hauling want is to take away function. But let’s face it: You read this magazine because you enjoy modifying your truck, and, like us, you have to ride that line between what looks cool, works best, and fits within the budget.

Pit Bull Tires has been making a name for itself on trails all over the U.S. From LT radials and bias-plies to UTV tires and more, Pit Bull’s aggressive styling and high-grip tread designs make your rig look its best and will pull you out of all sorts of trail messes.

Steered Strong But Wrong
Q I have a Chevy K10 that has a 14-bolt rear, a Dana 60 front, and 38x12.5x15 TSLs and uses Off Road Design’s crossover steering kit. Last year I was wheeling and broke a 10-bolt stub shaft in a twisty bog. Just before it broke I noticed I had absolutely no left-hand steering. Much reading led me to believe crossover steering would help by correcting the poor geometry of the stock GM steering system. After getting the 1-ton upgrade done, my power steering pump quickly gave up the ghost, screaming and puking fluid everywhere, which wasn’t too surprising to me; it had a hell of a hard life. I changed that out for a new one, and now it seems the truck has a left turn issue even sitting still! The truck needs to be rolling a little to steer left. I never had this issue with the 10-bolt/stock draglink configuration. All the steering components have been changed—2WD steering box, pitman arm, draglink, steering arm, axle—and I’m hoping I don’t need to go hydro-assist. I was really hoping the crossover steering setup would eliminate the loss of directional steering in trail twist situations, as well as be more mechanically advantageous against the big tires. There does seem to be a slight popping sound when steering, even when not rolling. Could bad kingpin bushings be causing the steering to bind in one direction or the other? Any suggestions you can throw my way would be greatly appreciated.
Curt N.
Via email