2018 GMC Sierra 1500 Wheel Alignment Specifications

Adjusting your 2018 GMC Sierra 1500's wheel alignment correctly is crucial for tire longevity, vehicle handling, and overall safety. This guide provides detailed specifications and essential information for maintaining proper alignment on your truck.

Quick reference

Note: "N/A" indicates that the angle is not applicable or not specified for that axle in standard alignment procedures.

Adjustability

The 2018 GMC Sierra 1500 offers some factory adjustability for alignment, primarily on the front axle. Knowing what can be adjusted and what requires aftermarket solutions is key:

• Front Camber and Caster: From the factory, these angles are typically adjusted by eccentric cams on the lower control arm bolts. These cams allow for a limited range of adjustment. If your vehicle has been lifted or lowered, or if the factory adjustment range isn't sufficient to bring the vehicle into specification, aftermarket cam bolts or adjustable upper control arms may be necessary to achieve proper alignment.
• Front Total Toe: This is the most commonly adjusted front alignment angle. Toe is adjusted by turning the tie rod ends on the steering linkage. This allows for precise setting of how much the front wheels point inward or outward.
• Rear Camber and Total Toe: On the 2018 GMC Sierra 1500, the rear axle generally has no factory adjustment for camber or toe. The rear axle is a solid axle design, meaning these angles are fixed. If rear camber or toe is out of specification, it often indicates a bent axle housing, worn axle components, or damaged frame, requiring repair or replacement of the affected parts. Some aftermarket kits exist to allow for minor rear toe correction, but these are less common for this specific vehicle due to its solid axle design.
• SAI (Steering Axis Inclination): SAI is a non-adjustable "diagnostic" angle. It is determined by the design of the suspension components. If SAI is out of specification, it typically points to bent suspension components like a spindle, ball joint, or control arm.
• Thrust Angle: Thrust angle is determined by the rear axle's alignment relative to the vehicle's centerline. While not directly adjustable on a solid rear axle, an incorrect thrust angle indicates a misaligned or bent rear axle, or potentially frame damage. Correcting it involves addressing the underlying issue with the rear axle or frame.

Recommended adjustment hardware

For situations where factory adjustments aren't enough, consider these options:

• Aftermarket Cam Bolts: If your front camber or caster is persistently out of spec after suspension modifications, extended range cam bolts can provide a greater adjustment range than OEM hardware. Brands like SPC (Specialty Products Company) or Moog often offer these for trucks.
• Adjustable Upper Control Arms: For significant lifts, adjustable upper control arms are often the most effective way to restore proper camber and caster, as they allow for substantial changes while maintaining optimal geometry.

Symptoms of bad alignment

Ignoring alignment issues can lead to costly problems. Watch out for these common signs:

• Uneven Tire Wear: This is the most obvious indicator. Different wear patterns point to specific problems:
  • Feathering: Sawtooth-like wear across the tread. Often indicates excessive toe-in or toe-out.
  • Camber Wear (inner or outer edge wear): One side of the tire is significantly more worn than the other. Indicates excessive positive or negative camber.
  • Cupping/Scalloping: Irregular dips or scoops around the tread. Can be a sign of worn shock absorbers, but also exacerbated by alignment issues.
• Vehicle Pulling: Your Sierra constantly drifts to one side of the road, requiring you to hold the steering wheel to keep it straight. This is often due to incorrect caster or camber settings, or significant differences between the left and right sides.
• Steering Wheel Off-Center: Even when driving straight, your steering wheel isn't perfectly horizontal. Typically a toe issue.
• Loose or Wandering Steering: The vehicle feels difficult to keep in a straight line, requiring constant small corrections. Can be caused by excessive toe-out or worn steering components.
• Vibrations: While often a wheel balance issue, alignment problems can sometimes contribute to vibrations, especially at higher speeds.

When to align

Regular alignments are a sound investment. Schedule one:

• After any suspension or steering component replacement: This includes ball joints, tie rod ends, control arms, shocks, and struts.
• After installing new tires: To ensure your new tires wear evenly from day one.
• After hitting a significant pothole, curb, or obstacle: Even if you don't notice immediate issues, an impact can easily knock your alignment out of spec.
• If you notice any of the alignment symptoms listed above.
• At least once a year or every 10,000-15,000 miles: As part of routine maintenance, especially if you drive on rough roads or perform heavy towing/hauling.

Typical alignment cost

The cost of a wheel alignment for a 2018 GMC Sierra 1500 typically ranges from $80 to $150. This can vary based on your location, the shop, and whether any seized components need extra labor to adjust. If specialty hardware or significant parts replacement is needed, the cost will increase.

Find a trusted alignment shop on Repairius.