Congratulations! You own one of the easiest 4-wheeled vehicles on the planet to align. Unfortunately, it is so simple, that many alignment shops seem to have forgotten how to do the job or lack the equipment to align large trucks with oversize tires. Couple that with OEM specs that don’t take into account larger than stock tires, and you can have a mess on your hands when you leave the alignment shop.
At CJC Off Road, we’ve heard the horror stories and decided it was time to shed light on the dark art of solid axle vehicle alignment. Whether you’re adventurous and take the job on yourself or you have a shop do the work, this guide will make sure it’s done right.
Before we get into the alignment process itself, let’s go over some basic steering nomenclature. The steering gear or box is connected to the Pitman arm, a short arm that transfers the rotation of the box to lateral movement of the steering linkage. The pitman arm is then connected to the drag link, which is then connected to the tie rod, On 2014+ trucks the drag link connects directly to the steering knuckle. The tie rod is the lower most steering linkage piece that connects the two knuckles at the ends of the axles together. If you sing that a few hundred times, you’ll remember which parts go where. If you’re more the visual type, check out the diagram below that has all the parts labeled.
The track bar is also a crucial part of your front end and steering. You won’t be able to steer without it! However, it’s not normally something that gets adjusted in an alignment. Ideally, it should be set when a lift is installed.
Different Steering Designs:
Above is a “Y” style or Haltenberger steering linkage. This style steering can be found under pre-2008 Rams with factory steering. It’s a faulty design that can cause drivability issues as a result of toe changes throughout the suspension cycle. Many of these trucks have had the steering replaced already under a Ram safety recall. Ideally, this steering should be upgraded to the 2008+ “T” style steering pictured below:
If you want to increase strength and reliability with oversize tires, go with our
2013+ 3500 and 2014+2500 trucks have a solid tie rod like the 2008+ “T” steering, so the following tips will also apply.
How Your Steering Works:
Now that we know where everything goes, let’s talk about what it does. The steering gear or box transfers your steering wheel input into a horizontal, rotational force. It also provides hydraulic assistance to your efforts with the help of the power steering pump. The Pitman arm is a lever that connects to the steering gear to the drag link. The shaft on the steering box that the Pitman arm bolts to is called the sector shaft. The pitman arm gives the steering gear the leverage it needs to push and pull on the drag link of your steering linkage. The drag link acts on the tie rod to push the tie rod in the direction you want to steer.
Now that we’re at the drag link, we’re at a piece that has an adjustment, and we’re all here for adjustments, right? Not yet! This will be the last adjustment we make. Think of it as the cherry on the top of a great alignment. Adjusting the length of the drag link allows us to center our steering wheel. Unfortunately, this is a detail that many shops gloss over.
All this pushing and pulling would do us no good if the two front tires weren’t pointing in the same direction, so we tie this thing together with our last piece, the tie rod. The tie rod ties the two steering knuckles together, and as such control the toe. Toe is the outward or inward angle of the two front wheels. This will be the first adjustment made when aligning the truck.
There is one more adjuster we’ll be utilizing to get our alignment dialed in. It’s integrated into the forward lower control arm bolts (radius arm bolts on late model trucks). These eccentric washers are the caster adjusters. Caster is the measurement of the forward or backward lean angle of the front axle and steering knuckles. If you have a radius arm truck, or have stock arms with vulcanized rubber bushings, loosen the forward upper arm bolts to allow the axle to move freely while adjusting caster. Pictured below are examples of the two different caster adjusters you’ll find, depending on the year of your truck. In both examples, the front of the truck is to your right. The picture on the left is an example of what you’ll find on 3500 trucks from 03-12 and 2500 trucks 03-13. To add caster, you’ll rotate the lobe of this adjuster toward the front of the truck. The adjuster pictured on the right is found on 13+ 3500 trucks, and 14+ 2500 trucks. To add caster, you’ll rotate the lobe of this adjuster toward the rear of the truck.
How to Align Your Truck:
It’s important to point out a vital and often overlooked step. Before starting, check for play in the steering. With the truck running, have a friend hop in and turn the wheel repeatedly left to right while you lay under the truck. Feel every joint in the steering linkage, including the track bar ends. If there is play, stop and replace the worn parts. That play will impact your alignment.
Step 1, Toe Angle:
Our first adjustment should always be toe. We’re not dealing with a stock truck here, so the specs the alignment shop has are not ideal. If you’re doing it yourself, you want zero to no more than 1/16” toe in. If you’re giving specs to the shop, ask for zero to 0.05 total toe. After the toe is set, move on to the caster adjustment. It is important that you have your toe set as close to zero as possible, this isn’t an IFS front end full of squishy bushings. If your front end components are in good condition, the tires will remain pointed where you set them. Pointing them toward each other (toe in) will result in increased tire wear, wandering, and can even negate the beneficial affects of our next adjustment, caster.
Step 2 Caster Angle:
Caster is the measure of the angle in the steering pivot point of the axle. At zero caster, the pivot points (ball joints in the case of a solid axle) will be at 12 and 6 o’clock. Increasing caster will push the lower ball joint toward the front of the truck. Positive caster is what makes the vehicle stable at high speed, and also helps your steering wheel return to center after a turn. By forcing the tires straight, caster also fights the dreaded death wobble. Like any good thing, too much is bad.
Symptoms of too much caster include: heavy steering feel, slow steering response, accelerated front driveshaft wear, and front driveshaft noise. Symptoms of too little caster include: wandering, twitchy steering, and sometimes death wobble.
The caster angle we’re shooting for here is +3.8-4.3 for Diesel trucks, and +4.2-4.8 for Hemi trucks. If you’re doing this in the driveway, and you’re working with approximately 3” of lift, start out with both adjusters straight up on non-radius arm trucks, or slightly rearward (one line on the stock radius arm) for late model radius arm trucks. If the truck drives well like that, leave it alone– don’t “fix it until it’s broken”. If you have any of the handling issues related to too much/too little caster, make small adjustments until your truck is driving straight, and responding appropriately to inputs. If you hear a growling noise coming from your front driveshaft after increasing caster, you have added too much caster. If you have to dial in so much caster that your driveshaft is singing the Blues, recheck your toe. If your toe is zero, and you are still having handling or return to center issues, you most likely have issues with one or more steering components.
If your truck has a slight pull to one side, you can add a small amount of caster to the side it is pulling toward. This will make the truck straighten out. This is referred to as "cross caster" use it sparingly.
A Few Notes on Caster
03-13 4-link Trucks
• The caster angle on these trucks increases as you lift the truck if the adjusters aren’t moved.
• Start with the adjuster at the 12 o’clock position for 2”-3” lifts. Beyond 3.5”, I recommend converting to a long arm or radius arm setup.
• Pointing the adjuster toward the front of the truck increases caster.
13+ Radius Arm Trucks
• Cross caster in these trucks can induce lean. If your truck is leaning when parked on a level surface, check to make sure your adjusters are pointing in the same direction.
• If you are running a quality lift coil, and it’s installed properly (I see them installed upside down or on the wrong side frequently), but you have a lot of coil bow, you probably need to rock those caster adjusters to the rear a bit.
• Pointing the adjuster toward the rear of the truck increases caster.
Tire pressures have a large impact on steering feel and wander at highway speeds. With the government mandating TPMS in vehicles, the question of proper tire pressure comes up quite often. The pressure that your government required nanny is telling you to put in your tires is probably not what your oversized aftermarket tires need. If you’re reading this, you most likely have oversized tires on your truck, so that thing in your dash really has no clue what you should be doing with your tires!
For determining the ideal highway driving tire pressure, you’ll need three things: a chalk stick, a flat parking lot, and an accurate tire pressure gauge. Having a mobile or on board air compressor is also handy.
Start by setting your tire pressure at the manufacturer recommended max value on the sidewall. Mark a line of chalk across the tread from edge to edge. Drive forward on a perfectly level section of pavement 50-100 feet, being careful to not turn. Get out, and check the chalk lines. If the chalk is worn off on the center of your tire but not the edges, your tires are over inflated. Drop 2-4 psi and start the process again. If the chalk is worn at the edges of the tread but not the center, your tires are under inflated. Repeat the process until the chalk wear is even across the whole tire. Keep in mind that the front tires will require a higher air pressure than the rears since they are bearing the weight of the motor. When towing, add additional air pressure to the rears to compensate for the extra weight. You can utilize a to get your pressure very close if you're not inclined to playing around with chalk. (I'm not a fan, but it's accepted as the go-to method for the meticulous.) The load/inflation tables will keep you safe, and are published by the tire manufacturers.