Buildup Basics

We spend a lot of time on the trail and in shops, and as a result we’ve seen many trucks. Some trucks are modified exceptionally well (they usually end up featured in the magazine). But for every good truck, there are many, many more that have been built poorly and caused the owner much grief that could have been avoided. We want to prepare you for what’s in store the second you start modifying your truck.

So before you get started, beware: When you change one component, it often requires an entire list of accompanying modifications. It’s important that you know this going in so you can budget your time and money accordingly. If you give up halfway, you’ll end up with an unsafe truck and a miserable ride, which could be more costly in the long run.

What Do You Do First?

Think. Put down the tools and gather your thoughts. You didn’t just buy your truck on a lark. You considered your needs, be it a pickup for hauling around loads, a tow vehicle, a family truckster, or something you feel is capable and fun to drive off-road. You need to put just as much thought behind modifying the truck. Ask yourself if you want to retain the truck’s current ride quality, its look, or its off-highway ability.

For example, some SUVs have a lot of tilt in cornering, or they nosedive during braking. Switching to high-pressure gas shocks and larger sway bars makes the suspension firmer, eliminates lean, and improves handling.

Maybe it’s a new look you’re after. Body bolt-ons, such as grilleguards and lightbars, are extremely popular because you can get a tough or European look, and most are easy to install yourself, even with little technical skill. However, most of these bolt-ons are for aesthetics alone—don’t expect much protection on trails.

But the most dramatic modification is a tire and wheel swap. Not only is it dramatic aesthetically, but it spawns a dramatic domino effect: Change the tires, and you’ll need to upgrade or change many other components throughout the vehicle to make the most of the larger treads.

Fresh Meat

The most common first modification is a switch to larger tires. But what kind? Mud tires look aggressive, but if you do more highway driving than off-roading, they’re not a realistic switch. To get through the goop, these tires have wide spaces between the lugs. That works well in the mud, but they’ll hum while you’re driving on the street, which some people can’t tolerate. Go with all-terrain tires instead.

And you’re probably just like everyone else—you want the biggest tires possible. Before you buy, know the flex and suspension travel of your truck. If you push the huge-tire envelope, you might run into a few problems. One is that the tires will be too wide and stick out. Another possible problem is that the tires can rub the fenderwells or the frame. A little bit of rubbing is OK—sometimes it fixes itself, but if not, you can trim the sheetmetal or limit the turning radius.

Chain Reaction

The tires are on, and your truck looks trick. But guess what? By simply swapping those tires you’ve opened up multiple cans of worms.

The first problem affects owners of late-models. The speed-sensing device tracks speed for the speedometer and the electronic control module. With the new tires, the sensor tells the computer that something is wrong. To fix this, recalibrate the speedo.

Smooth the Ride

If you’re not making any other suspension changes after new tires, change the shocks because the bigger tires weigh more and will probably overwork the stock shocks.

Brake Yourself

Larger tires mean the rolling resistance is greater. In other words, it takes more power to get the big tires moving, and the stock brakes take longer to stop your truck. Bigger tires really need better brakes. Upgrade your brakes, such as to a semimetallic compound.

Running Out of Energy

Perhaps the most noticeable difference you’ll see in your truck as a result of larger tires is a loss in power. A solution is a gear-ratio change. With the taller tires, you should make the gearing lower (numerically higher), such as from 3.73 to 4.10.

Big Wheels Keep On Turning

Another modification that can accompany larger tires is an axle swap. Bigger tires weigh more thereby increasing the weight put on the axle. Consider a stronger assembly as a preventative measure—also a good idea if you’re going to lift your truck.

And Speaking of Lifts...

Another solution to the too-tall-tire scenario is to lift your truck. First, let’s talk don’ts and myths.
•Don’t use front blocks. Don’t use front blocks. Don’t use front blocks. They increase axle wrap, and if one slips, you might lose control of the vehicle. They’re an easy way to achieve lift, but they’re far too dangerous. Don’t use front blocks. Besides, they’re illegal in most states.
•Shocks won’t increase ride height. Shocks don’t give your truck a lift or affect spring rate. They need to be fitted to the suspension, not the other way around.

Getting a Rise

Kits are made to lift the body or the suspension, and some people use a combination of kits. A body lift raises the body off the frame, and a suspension lift increases the distance between the axles and the frame. A combination of lifts is generally used when the owner doesn’t want to start slicing the body to accommodate big ol’ tires.

The bad news for late-model truck owners is that it’s more complicated to perform a lift yourself. Suspensions have become more complicated, so you should take your truck to a professional who fully understands the modern technology, such as the computer and the ABS.

However, you can increase the height of a truck with IFS by a maximum of 1 ½ inches by cranking up the torsion bars. But the torsion bars are springs, so if you increase their preload in this manner, the suspension becomes stiffer.

Lines, Shocks, and ’Shafts, Oh My

Almost all kits include the necessary new parts to accommodate the suspension changes. But parts that are really needed could be considered options in some kits. A few musts: shocks and axles. After you install a suspension-system kit, the old shocks will be forced to fully extend, and the lack of compression could cause them to rip out as you drive over a bump. If you give your truck a 4-inch lift, it really needs 4-inch taller shocks.

Of course, the lift presents some other modifications. You may need to lower the transfer case if there’s too much angle on the driveshaft or too much driveshaft vibration, and some of the 2 ½-inch–lift kits for Jeeps include a T-case lowering kit for the job. Have you ever seen someone stranded on the side of the road because the driveshaft fell out of his truck? Increased pinion angle wears out the U-joints, so keep the lift mild enough that the pinion angles aren’t severe.

You may also need to lengthen the driveshaft. There should be enough length with a lift of 3 ½ or 4 inches, but check that there is still more than 1 inch of enjoyment when the truck sits on level ground. If not, it’s time to lengthen.

The brake lines are attached to the frame and suspension, so when you increase that gap, you may need to lengthen them too.

Other could-happens or should-happens are exhaust modification, a dropped pitman arm, and bushings.

More Food for Thought

Another good first modification for your truck concerns open cabs. It’s a safety tip: Install a rollbar or a rollcage. And put plates underneath the mounting points for safety.

There You Have

Modifying your vehicle from scratch should be fun. You’re building a truck, and you’re doing it the way you want it. This is an enjoyable experience, and having your hard work show in a well-built vehicle makes it all worth it. We’ve discussed some of the most common first modifications made to a stock truck. But don’t be discouraged by the trickle-down theory—be prepared. Knowing what you’re in for will help you build a reliable and capable truck.