Aligning a car means setting two wheels at the front. Aligning a heavy truck means managing several axles that all have to work in the same direction. It is a different game, and it takes equipment and experience you only build by working on heavy trucks.
At Ressorts Laval, multi-axle alignment is part of our daily work. It is one of those services where the difference between a car shop and a heavy truck specialist shows up directly on your tire bill.
The problem with multiple axles
On a heavy truck, you don’t just have a steer axle up front. You also have one or more rear axles (often in tandem), and across the whole rig, the trailer axles. If even one of these axles pushes off-angle, the whole truck runs crab-wise, even with the wheel straight.
Each axle must not only have its own angles correct, but also be positioned correctly relative to the others and to the frame. On a tandem, the two rear axles must be parallel to each other and square to the frame. The slightest offset and the truck starts to walk sideways.
Thrust angle
This is the key concept of multi-axle alignment. The thrust angle is the actual direction the rear axles push the truck. If the rear axles are not perfectly aligned with the frame, they push slightly to the side. The result: the driver has to hold the wheel a little turned to run straight, and the tires wear on a slant.
We measure the thrust angle relative to the frame centerline (the geometric center line). On a leaf-sprung rear axle, we often correct its position with shims or by adjusting the torque rods. It is precision work: setting the front to compensate for a bad thrust angle hides the problem, it does not fix it.
💡 A truck that runs crab-wise (dog tracking) from a bad thrust angle wears its tires, raises fuel consumption and tires out the driver. It is invisible to the eye but it costs money month after month, especially across a fleet.
The return on investment: tires and fuel
Multi-axle alignment is not an expense, it is an investment you can calculate. On a heavy truck, a set of tires is thousands of dollars, and bad alignment can eat half their useful life. Add the rolling resistance of a truck pushing sideways, and you get extra fuel use that comes back at every fill-up.
For a fleet, these losses multiply by the number of trucks and trailers. That is why smart fleet managers build alignment into their preventive maintenance: the cost of an alignment is almost always less than the tires and diesel it saves.
Why total alignment matters
A proper heavy truck alignment is not limited to the steer axle. We check the alignment of all axles relative to each other and to the frame. That is what is called a total alignment. It is the only way to make sure all axles work in the same direction.
⚠️ Warning
Aligning only the front axle of a heavy truck fixes half the problem. If the rear axles or trailer are off, the tire wear and excess fuel use continue. On multi-axle, complete alignment is essential.
Signs you need a multi-axle alignment
Here is what should push you to have the complete alignment checked, not just the front:
- The wheel stays off-center while you drive in a straight line
- Tires wearing on a slant on more than one axle
- The truck appearing to run crab-wise, visible when someone follows you
- Fuel consumption climbing with no obvious mechanical reason
- A pull that persists even after the steer axle has been set
If you notice one of these signs, it is rarely just the front. It is often a rear or trailer axle pushing off-angle, and only a total alignment reveals it.
Equipment and experience
Multi-axle alignment takes machines built for heavy trucks (not cars) and a mechanic who knows the specs of each configuration. In Laval, we have two alignment machines for heavy trucks, able to handle 10 and 12-wheel configurations as well as light trucks. That is the difference between an alignment that holds and one that does not.
Frequently asked questions
What is dog tracking?
It is when a truck runs slightly sideways because the rear axles don’t push in line with the frame. Tires wear and fuel use climbs.
Should the trailer be aligned too?
Ideally yes. Misaligned trailer axles cause the same wear and fuel problems as the tractor’s.
Can a car shop align my heavy truck?
Rarely well. It takes machines built for heavy trucks and experience with multi-axle setups.
How often should a heavy truck be aligned?
As regular maintenance, after a major impact, and as soon as abnormal tire wear appears.
How long does a multi-axle alignment take?
Longer than a car, because we measure and set several axles. The exact time depends on the configuration and the condition of the mechanicals, which we check first.
Does a total alignment include suspension and steering?
We check them first, because an alignment does not hold on worn parts. If we find play or wear, we tell you and give you a price before proceeding.
Tires wearing on a slant or your truck running sideways?
It is often a multi-axle alignment to set. At Ressorts Laval, we have aligned 10 and 12-wheel heavy trucks for decades.
Call us at 450-661-5157.