2015 Kenworth T680 Wheel Alignment Specifications

Keeping your heavy-duty truck tracking straight down the highway is critical for fuel economy, tire life, and driver fatigue. As an ASE-certified alignment technician, I know that Class 8 trucks like the 2015 Kenworth T680 require a different approach to alignment than passenger vehicles. With solid steer axles and tandem drive axles, understanding the factory specifications and adjustment methods is essential for maximizing your cost per mile.

Below, you'll find the comprehensive alignment specifications and adjustment guide for the 2015 Kenworth T680.

Quick reference

The following table provides the standard heavy-duty alignment specifications for a 2015 Kenworth T680. Note: Drive axle (rear) camber and toe are machined into the solid axle housing and are generally not adjustable unless the housing is bent. Rear preferred/range values for those angles refer to acceptable tolerances before axle replacement or specialized correction is needed.

Adjustability

Adjusting a Class 8 truck like the 2015 Kenworth T680 is significantly different from adjusting an independent suspension light truck.

Front Axle (Steer):

• Total Toe: This is the most commonly adjusted angle and is fully adjustable from the factory via the cross tube (tie rod) connecting the two steer knuckles.
• Caster: Caster is adjustable, but not by simply turning a bolt. It requires installing angled steel or aluminum caster wedges (shims) between the leaf spring pack and the steer axle pad.
• Camber & SAI: Camber and Steering Axis Inclination (SAI) are machined into the solid steer axle beam. They are not traditionally adjustable. If camber is out of specification, it usually indicates a worn kingpin, a bent axle beam, or failing wheel bearings. Some specialized heavy-duty shops can cold-bend the axle to correct camber, though replacing worn components is the factory-approved method.

Rear Axles (Drive):

• Thrust Angle (Tandem Axle Alignment): Tracking is highly adjustable and extremely important on a T680. Depending on the exact rear suspension option (such as the Kenworth AG400L), thrust angle and tandem scrub are adjusted by shimming the torque rods, adjusting threaded longitudinal torque rods, or rotating eccentric collars at the suspension hangars.
• Rear Camber & Toe: Non-adjustable. These are set by the rigid drive axle housing. Deviations indicate a bent axle housing requiring heavy repair or replacement.

Recommended adjustment hardware

When aligning a 2015 Kenworth T680, you rarely use the cam bolts found in passenger cars. Instead, a heavy-duty alignment shop will need:

• Caster Shims/Wedges: High-quality steel or aluminum axle wedges (typically available in 0.5°, 1.0°, and 2.0° increments) to adjust steer axle caster.
• Torque Rod Shims: Barbed or slotted shims used at the frame brackets of the drive axle suspension to adjust tandem axle tracking and thrust angle.
• Adjustable Torque Rods: If the factory fixed torque rods are worn, replacing them with aftermarket threaded adjustable torque rods makes squaring the drive axles much easier and more precise.

Symptoms of bad alignment

Tire wear on a commercial truck eats into profits rapidly. Watch for these common signs of alignment issues on your T680:

• Feathering on steer tires: Usually indicates an incorrect toe setting. If the tread blocks feel smooth when rubbing your hand inward but sharp outward, you have excessive toe-in.
• One-sided shoulder wear: Smooth wear on the inside or outside shoulder of a steer tire typically points to a camber issue (or a failing kingpin).
• Diagonal wear or cupping on drive tires: Often caused by the drive axles being out of square (incorrect thrust angle/tandem scrub), forcing the tires to drag sideways down the road.
• Steering wheel off-center or pulling: If the truck pulls constantly to one side, you may have a caster split issue, or the drive axles are dog-tracking and pushing the truck sideways.

When to align

For a Class 8 over-the-road truck, preventative maintenance is key. You should perform a three-axle alignment on your 2015 Kenworth T680:

• Every 80,000 to 100,000 miles as part of a routine preventative maintenance schedule.
• Whenever replacing the steer tires, to protect your new investment.
• After replacing any steering or suspension components, including tie rod ends, kingpins, leaf springs, or torque bushes.
• After hitting a severe pothole, curb, or road debris that causes a jarring impact to the steer axle.
• If drivers report handling issues, wandering, or fighting the steering wheel to keep the truck straight.

Typical alignment cost

Because aligning a commercial heavy-duty truck requires specialized heavy racks, specialized lasers, and heavy labor (such as loosening U-bolts to install caster wedges), the cost is higher than a standard vehicle. A basic three-axle alignment check and toe adjustment on a 2015 Kenworth T680 typically ranges from $250 to $400. If caster wedges need to be installed, or if the tandem torque rods are seized and require significant labor to adjust the thrust angle, the total cost can easily range from $450 to $700.

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