Maintenance & Care
Alignment
Proper Alignment Lowers Operational Costs and Extends Tire Life.
Ideally, when a truck traveling is in a straight line, all of the axles are parallel and perpendicular to the vehicle centerline, and all the tires are rolling in a straight line.
Proper alignment can help maintain ideal fuel economy, reduce tire and component wear and even reduce driver fatigue.
Most alignment issues can typically be attributed to two primary factors: toe settings and axle alignment.
Toe Settings
Toe Angle identifies the direction of the tires compared to the centerline of the vehicle.
When drive tires propel a vehicle with improper toe settings forward, there is an increase in rolling resistance that negatively impacts fuel-efficiency, ride comfort, and shortens tire life.
The vehicle’s toe is the most critical alignment settings relative to tire wear. If the toe setting is just 1/32" off of its appropriate setting, each tire on that axle will scrub almost 3.5’ sideways every mile, significantly reducing tire life.
Toe-In
An axle has “toe in” when the imaginary lines created by the tires intersect in front of the vehicle. The distance between the front of the tires is less than the distance between the rear of the tires.
Toe-in puts extra force on the outside of the steer tires, causing outside shoulder wear.
Toe-In is the most basic front-end setting, and is typically set at 1/16" toe-in. Measured & set in a static state, toe-in allows wheels to run straight when the vehicle is loaded rolling down the highway.
Toe-Out
An axle has “toe out” if they diverge and the distance between the front of the tires is greater than the distance between the rear of the tires.
Toe-out puts extra force on the insides of the steer tires, causing inside shoulder wear.
Misaligned Drive Axles
There are two types of misaligned drive axles that require constant steering inputs to keep the vehicle straight: skew misalignment and thrust angle misalignment.
Skew misalignment exists if the drive axles aren’t parallel, pushing the vehicle to the right or left of center.
A thrust angle misalignment exists if the drive axles are parallel to each other but are not perpendicular to the frame, also pushing the vehicle to the right or left of center.
Standard Right Thrust
Standard right thrust occurs if the vehicle’s drive axles are pushing the truck to the right. Wear on the right steer tire will mimic toe-in wear, while the left side will exhibit the feathering associated with toe-out alignment.
Standard left thrust occurs if the vehicle’s drive axles are pushing the truck to the left. Wear on the left steer tire will mimic toe-in wear while the right side will exhibit toe-out wear.
There are also combinations of both toe and axle misalignment, which will put stress on just one steer tire. Here, the toe-in setting combined with right thrust misalignment causes the left front to wear normally while the right front feels like toe-in.
On the other hand, toe-out combined with right thrust will cause the front right to wear normally but places stress on the left, resembling toe-out.
