2017 Kenworth W900 Wheel Alignment Specifications

Quick reference

Adjustability

On the 2017 Kenworth W900, front axle total toe and individual toe are factory adjustable. This is typically done by adjusting the tie rod ends. Caster is also adjustable at the factory, usually through eccentric bushings or shims at the leaf spring mounts or axle housing pivots, depending on the specific front suspension setup. Camber on the W900 is generally not factory-adjustable. If camber is out of specification, it usually indicates a bent axle, worn kingpins, or worn suspension components. Correcting camber on a heavy-duty truck often requires replacement of the affected components or specialized aftermarket solutions like shims or offset kingpin bushings.

The rear axles of the Kenworth W900, being drive axles, have limited alignment adjustability. The primary adjustable angle on the rear is total toe, which can be adjusted on some chassis through shims or eccentric mounts for the leaf springs or control arms. However, many heavy-duty truck rear axles rely on proper component installation and an undamaged chassis for correct alignment. Thrust angle is a critical rear-end measurement but is not directly adjustable. Instead, it's a result of the individual toe settings of the rear axles relative to the vehicle's centerline. Correcting thrust angle typically involves adjusting the toe on one or more rear axles or addressing any bent or shifted axle housings.

Recommended adjustment hardware

For most Kenworth W900 models, standard heavy-duty tie rod ends are used for toe adjustments. For caster adjustments, eccentric bushings or shims provided by Kenworth or reputable aftermarket manufacturers are utilized. If camber is persistently out of spec despite addressing worn components, specialized aftermarket solutions such as offset kingpin bushings may be considered, but extensive expert diagnosis should always precede such modifications.

Symptoms of bad alignment

Uneven Tire Wear

• Feathering: This occurs when the tread ribs are worn smooth on one side and sharp on the other. It's often an indication of excessive toe-in or toe-out.
• Cupping/Scalloping: Irregular dips and hollows around the tire's circumference suggest worn suspension components (shocks, ball joints, kingpins) or unbalanced tires, but can also be exacerbated by alignment issues.
• Edge wear: Excessive positive or negative camber will cause accelerated wear on one edge of the tire. Positive camber wears the outer edge, negative camber wears the inner edge.
• Center wear: While often a sign of overinflation, center wear can also be influenced by overall toe settings if leading to excessive scrubbing.

Steering Issues

• Pulling or Drifting: The truck constantly wants to veer to one side, requiring the driver to apply steering input to keep it straight. This can be caused by incorrect camber, caster, or excessive thrust angle.
• Loose or Wandering Steering: The truck feels unstable on the road, requiring constant corrections to maintain a straight path. Low caster or worn steering components are common culprits.
• Hard Steering: While not solely an alignment issue, incorrect caster can contribute to a heavy steering feel.
• Off-Center Steering Wheel: The steering wheel is not straight when the truck is traveling in a straight line, but the truck drives straight. This is usually due to an incorrect toe adjustment without centering the steering wheel.

Reduced Fuel Economy

Misaligned wheels create increased rolling resistance, forcing the engine to work harder and reducing fuel efficiency.

When to align

It is recommended to have your 2017 Kenworth W900's wheels aligned:

• After any suspension or steering component replacement: This includes kingpins, tie rods, drag links, leaf springs, spring hangers, or any components affecting axle geometry.
• After replacing a tire or set of tires: New tires provide a fresh baseline for alignment and can sometimes highlight existing issues.
• After hitting a significant pothole, curb, or other road hazard: A severe impact can bend or shift alignment components.
• If you notice any of the "Symptoms of bad alignment" listed above.
• As part of routine maintenance: Many heavy-duty truck operators opt for annual or bi-annual alignments, or every 50,000 to 100,000 miles, depending on operating conditions and mileage.

Typical alignment cost

The cost of a commercial truck wheel alignment for a 2017 Kenworth W900 can vary significantly based on location, shop rates, and whether any adjustments or suspension repairs are needed. On average, a basic steer axle alignment might cost between $150 and $300. A full three-axle or multi-axle alignment (steer and drive axles) for a heavy-duty truck can range from $300 to $700 or more, especially if specialized equipment or extensive adjustments are required. Always obtain a detailed quote from a trusted shop.

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