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Double Duty

Posted in How To on January 1, 2013 Comment (0)
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Building a vehicle that works well both on- and off-road can be a challenging endeavor. For many it simply breaks down to basic math. If you spend 70 percent of your time driving on-road and only 30 percent off-road, it doesn’t stand to reason that you would concentrate all of your vehicle modifications on such a small fraction of your seat-time, right? Wouldn’t it be nice if it actually worked that way?

The reality is that having a daily-driver that doubles as your weekend trail rig is a delicate dance. You have to keep in time with your daily rhythm, while not dropping out of sync with the requirements you need to survive off-road. While it may seem impossible to satisfy both needs, we assure you that it is not. Modern 4x4s, aftermarket parts, and build theories have evolved substantially over the years. Sure, an early ’80s Chevy pickup on 40s isn’t an ideal candidate for a daily-driver, but mix in modern technology such as fuel injection and gear underdrives, and it doesn’t seem that farfetched.

The key is to build your vehicle in a way that focuses on realistic expectations and goals. We understand that not everyone can fork over the dough for the best-of-both-worlds parts. For this reason we’ve broken down our double-duty, must-have list into three categories: best all-around, middle ground, and budget-friendly. Don’t be afraid to mix and match to find the perfect combination for you.

Skidplates
One of the trickiest feats when building a double-duty rig is lifting it high enough to have underbelly clearance, but not so high that you look like an amateur gymnast every time you enter and exit the vehicle. We prefer a low center of gravity on our trail rigs, but understand that means keeping your rig’s vital drivetrain components closer to the ground. Skidplates and rocker guards are a big part of protecting your expensive components, and they keep your 4x4 looking sharp for the weekly commute. Keep in mind that every plate you bolt or weld onto your rig adds weight. Additional weight can pull down performance, fuel economy, and place more stress on drivetrain components. Add cautiously and don’t be afraid to venture to aluminum guards for weight savings.

Best all-around: Oil pans skids, heavy-duty diff guards, body panel-plating, and rock sliders are all great ways to preserve your 4x4. Aluminum options for some of the items will keep the weight down while offering similar protection. The price point will be higher for aluminum, but avoiding the pounds is the best way to keep up your rig’s performance and economy.

Middle ground: Skidplates and body protection can get pricey quickly, especially if you are outside of the aftermarket megalopolis of the Jeep world. If you’re running an automatic transmission, we suggest at least an oil skidplate for protection. Rock sliders would be next on the must-have, as they will keep your doors functional and your boss from thinking you are a terrible driver.

Budget-friendly: If you are handy with a drill and have a local junkyard nearby, your rig’s underbelly protection might be easier to come by than you think. Countless makes and models were fitted with factory skids (mostly gas tank and transfer case), and with a little imagination can be transferred to your ride.

Wheels
Wheels are a huge part of what gives the vehicle its identity and can place you apart from an everyday mall-crawler. We are huge fans of aluminum beadlock wheels for their strength, light weight, and functionality. Being able to drop into single-digit air pressure is a tremendous advantage for your vehicle off-road. At lower psi the tire will absorb and conform to the terrain more effectively, which equates to increased traction and less stress on your rigs components. The lower pressure also acts as a secondary suspension of sorts, which translates to a smoother ride off-road. Compared to a standard steel wheel, beadlocks are very pricy. If you plan on regularly pushing the limits of your 4x4, then they are worth the investment. If light trail riding and backwoods exploring is more your thing, then don’t feel like beadlocks are a must-have. Be sure to investigate how much the wheel weighs. An extra 10 pounds at the wheel is the equivalent of 100 pounds of cargo inside of your rig.

Best all-around: A DOT-compliant aluminum double-beadlock offers the best of both worlds. There will be no gray area for driving with them on-road, and you’ll get all of the performance advantages off-road. They are not extremely light, but won’t be as cumbersome as steel versions.

Middle ground: A more traditional exterior-locking, ring-style aluminum beadlock is a great investment. If beadlocks are simply not in the budget, then look into an aluminum wheel set.

Budget-friendly: A simple set of steel wheels will provide you plenty of good years of wheeling. The steel construction actually edges out the aluminum a bit in terms of reliability off-road. If you bend the lip of a steel wheel, you can usually beat it back in place with a hammer. There will be a weight penalty with the steel wheel, which can affect your fuel economy and performance.

Suspension
When it comes to suspension systems there are seemingly endless avenues to travel. The ultimate goal for any double-duty 4x4 is to have a durable and well-engineered suspension system that allows for a smooth ride both on- and off-road. Coilover shocks and custom link-suspensions are great ways to get serious performance and travel, but expect to pay a premium for the high-end suspension performance. Sometimes a simple shock upgrade can make a tremendous difference.

It’s also important to find ways to improve your suspension without completely taking away its functionality. For example, using air bags to compensate for softer long-travel leaf springs in the rear of a truck will offer increased off-road performance without deleting the functionally and payload capacity of your workhorse. Suspension upgrades can often be had a little at a time, so take it slow and figure out what’s best for your needs.

Best all-around: A rebuildable shock from companies like King (www.kingshocks.com), Fox (www.foxracingshox.com), and Bilstein (www.bilstein.com) will allow you to finely tune your 4x4. Depending on your make and model, long-travel suspension kits are worth looking into. Many of the modern performance suspension systems can net you tremendous amounts of travel, while maintaining suitable road manners.

Middle ground: Shocks are a huge part of the suspension equation so at the very least get a set that is properly tuned and rebuildable. A shock that you can valve and build is one that can grow with you and your rig. Research suspension systems that focus more on vertical wheel travel instead of just lift numbers.

Budget-friendly: Don’t be too frustrated by the sticker shock of what suspensions cost these days. There are plenty of entry-level systems that are very affordable and work great off-road. Remember, inexpensive doesn’t always mean cheap quality. By simply disconnecting your sway bars and installing longer shocks, you can easily increase the performance of your stock suspension off-road.

Front Bumpers
Keeping your 4x4 low might sound easy enough, but a low COG (center-of-gravity) can absorb much of your rigs approach angle. This is especially true for modern 4x4s equipped with an extremely low-hanging front bumper. Stock bumpers adhere to strict federal safety standards and have aerodynamic cues built-in to help the truck’s overall efficiency. Upgrading your front bumper with a high-clearance unit will up your ground clearance, allow room for larger tires, and increase the vehicle’s approach angle. Just as we mentioned with the skidplates, weight plays a big role in the performance of your rig. Aluminum is a great option for some rigs, but we’re fans of simple DOM tube-style bumpers for simplicity and clearance. Your front bumper is the first thing to get smashed off-road, so pick something that is meant to take a beating. Basic brushguards will not cut it.

Best all-around: Plate bumpers similar to those offered from ARB (www.arbusa.com) usually flow well with factory body lines and can be painted to match. The drawback of a large plate-bumper is that they often decrease the approach angle over a tube-style front bumper. Much of the bumper decision comes down to personal preference and bumper availability.

Middle ground: High-clearance is the name of the game off-road. Don’t fret if you can’t get that ultimate winch and bumper you’ve been looking at. Look for a simple and lightweight front bumper that has tow-point attachments. Tube bumpers may look a bit more aggressive, but are often much lighter and offer more clearance over plate-style bumpers.

Budget-friendly: There are a few ways to trim your stock bumpers to create more clearance while keeping a clean look. Don’t be afraid to leave the stock bumpers at home either. Taking a few minutes to drop the factory guards might sound like a time burglar, but come Monday morning you’ll be glad you did it.

Lockers
A differential locker is mechanism that sits inside of or replaces the differential carrier. The job of a locker is to “lock” both axleshafts in unison so they can rotate at the same speed. Most factory 4x4s are equipped with an open differential carrier, which allows for different speeds of the tires as they move through different arcs of a turn. This open-style differential only sends power to the wheel with the least resistance, where a locker actually splits the power between both wheels evenly. A locker, especially in the rear, will be one of the best investments and noticeable performance modifiers that you can place in your rig.

Best all-around: Selectable lockers are the cream of the crop for a daily-driven vehicle. On-road, most selectable lockers work identically to an open differential when not engaged. This means your rig’s street manners will be unchanged. With the simple flick of a switch or pull of a lever a selectable locker transforms into a type of spool, which engages the axleshafts to spin at the same speed. Selectable lockers are the costliest style of locker, but for those that spend the most amount of time on-road, they are a great investment.

Middle ground: Automatic lockers like the Detroit Locker (www.eaton.com) are full-carrier replacement lockers that automatically engage when power (throttle) is applied. Generally, this style of locker allows for wheel-speed differentiation for turning, and in longer wheelbase vehicles, is not very noticeable on-road. Differences in air pressure and short-wheelbase rigs like the Jeep Wrangler can bring out quirky handling characteristics. This style of locker is usually about half the price of a selectable locker and ranks high on our favorite list for their sheer strength and simplicity. If you can only pop for one locker, put it in the rear axle.

Budget-friendly: Lunch-box or drop-in-style lockers are a great for those building on a limited budget. Drop in style lockers go in-place of the spider-gears inside of an open differential. They work similar to the full-carrier replace automatic locker, but they are often noisier. Since you are re-using your factory open differential carrier, you don’t get the strength upgrade of the aftermarket carrier. Drop-in lockers are a little less costly than full-carrier replacement lockers, and can easily be installed in your driveway with basic tools. Again, if we had to choose a spot for only one, it would be in the rear axle.

Tires
Tires are a tricky equation, as much of what people need out of a tire can be specific to their region or job occupation. If you haul heavy-loads with your double-duty rig, then a Load Range E tire makes sense for you. If the heaviest load your wheeler sees is a cooler and hunting gear, then a lighter Load Range C tire will work just fine. For those fortunate enough to live in an extremely dry climate, we suggest looking into an aggressive all-terrain tire.

The term aggressive all-terrain may sound like an oxymoron, but many of the newer all-terrain varieties have the bulky lugs similar to a mud-terrain with a more staggered tread spacing. All-terrain tires will help keep the noise and rolling resistance down, which equates to better fuel economy and quiet drive. If mud is anywhere near you, buy a radial mud-terrain. Many of the modern radial mud-terrains are extremely quiet and long lasting. Trust us- you don’t want to be the guy that is constantly being winched along the trail because your all-terrain tires can’t bite in the slop.

Best all-around: Radial mud-terrains for those looking to churn up loose dirt and a radial all-terrain for those avoiding the sticky stuff like the plague.

Middle ground: A radial mud-terrain is always a safe bet. There will be more compromise in regards to road noise and tread wear, but the off-road performance will be well worth it. Again, if you wheel in rocks and the desert, an aggressive all-terrain is worth a look.

Budget-friendly: We’ll stick with a radial mud-terrain again as our choice tire. You may not be able to score the high-dollar name-brand version, but even an off-brand mud-terrain will be a better fit for the occasional wheeler than a standard all-terrain.

Drivelines
The modern factory driveshaft as we know it is pretty pathetic. Most stock drivelines are oversized, thinly-walled, and aluminum. All of those features are great for fuel economy and vehicle harmonics, but don’t cut it in rough and rocky terrain. Upgrading to a more durable set aftermarket drivelines from companies like Tom Woods (www.4xshaft.com) and J.E. Reel (www.reeldriveline.com) will not be cheap, but the shafts’ will practically pay for themselves each time you churn them into some off-road obstacle. A driveline upgrade is especially important for longer wheelbase rigs were the drivelines are more susceptible to damage.

Best all-around: Front and rear driveshafts will be money well spent and a more piece of mind over the stock light-duty shafts.

Middle ground: If you don’t want to swing for the matching set of heavy-duty drivelines, at least upgrade the rear. This will keep you from missing work on Monday when your factory ’shaft gets peeled open on a rock over the weekend.

Budget-friendly: When aftermarket drivelines simply are not in the budget, it’s time to take a trip to your local junkyard. You don’t have to carry a crazy amount of spare parts on the trail, but keeping a rear driveline on hand will make those out-of-town wheeling outings a lot less stressful.

Steering
Steering is a spot where we often see people skimp out. Don’t do it! There are great steering upgrade options for all makes and models. If turning those 37-inch and up treads is becoming a challenge on- and off-road, then we suggest looking into hydraulic-assist steering. Adding a hydraulic-assist steering cylinder will even-out the steering component load. For vehicles equipped with a traditional steering gearbox this is especially important. We’ve seen plenty of broken gearboxes and sector-shafts on the trail and it is not an easy or cheap fix.

Best all-around: For applicable rigs, hydraulic-assist is a great way to go. This will ease the steering load on your components and reduce the challenge of day-to-day maneuverability. For rigs on the milder side, steering link upgrades or a high-steer system will suffice.

Middle ground: If your rig is equipped with a solid front axle then a high-steer knuckle and heavy-duty steering link setup is a great option. If your rig is IFS then look into heavy-duty link ends. Companies like CST Suspension (www.cstsuspension.com) have bolt-on link upgrade kits for vehicles like the ½- and ¾-ton IFS Chevy trucks and SUVs.

Budget-friendly: Steering upgrades are never dirt cheap, but companies like Rough Country Suspension (www.roughcountry.com) offer inexpensive tie-rod sleeves to create a little extra steering beef.

Differential Gearing
Gears are one area where you simply cannot afford to cheap out. When you outfit your 4x4 with larger tires, you need gears to compensate. Swapping in a numerically higher gearset, along with your taller tires will place the rpms closer to stock. This reduces the strain on your engine and transmission. Placing your rpm range back within the factory parameters will equate to improved performance and fuel economy. If you happen to have a rather anemic engine, don’t be afraid to go a little higher numerically with your differential gear choice. This will only improve the vehicle control in the dirt and on the street.

Best all-around: Differential gears with a highway-friendly ratio will likely serve you best. Consult your local gear technician and rpm chart to find what gear ratio is right for your rig.

Middle ground: A gearset that is a touch higher (for example, a 5.13 versus a 4.88) will give you more control off-road. The higher numerical gear set may cause the engine to rev more on the freeway, but around town the added torque multiplier will be a bonus.

Budget-friendly: If re-gearing simply isn’t in the cards then we suggest building your rig accordingly. This means limiting the tire size to help maintain the effectiveness of the stock ratios. You will have way more fun with 31s and power on tap, than bogging around on 35s with nothing left to give.

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