2019 Peterbilt 579 — Tire Size & Pressure

Quick answer

• OEM Tire Size: 11R22.5 (steer and drive axles are common)
• Recommended Cold Tire Pressure (Door Placard): Typically 100-110 psi for steer axles, 85-100 psi for drive axles (will vary based on load and tire type)
• Bolt Pattern: 10-lug (285.75mm bolt circle diameter)
• Wheel Size: 22.5 x 8.25 inches (common for steer and drive)
• Load Index/Speed Rating: Varies significantly based on tire application (e.g., steer, drive, trailer), often a G or H load range with speeds up to 75 mph (L speed rating)
• Spare Tire Size: Identical to road tires (11R22.5 is common)
• TPMS Frequency: 433 MHz (common for heavy-duty trucks)

Tire sizes by trim

The Peterbilt 579 is a heavy-duty truck designed for various applications, and tire sizes primarily depend on the specific configuration and intended use rather than distinct "trims" like passenger vehicles. The most common OEM tire size is 11R22.5 for both steer and drive axles. However, other sizes are available to suit different operational needs.

• 11R22.5: This is a very common size, offering a good balance of load capacity, ride comfort, and availability.
• 295/75R22.5: Often used for a slightly lower profile and sometimes seen for fuel efficiency gains.
• 315/80R22.5: Provides a higher load capacity, often used in vocational applications or where maximum front axle loading is required.
• 275/80R22.5: A slightly smaller diameter option which might be chosen for specific gearing or clearance needs.

Recommended replacement tires

When replacing tires on a 2019 Peterbilt 579, consider the specific application (long haul, regional, vocational), expected load, and desired characteristics such as fuel efficiency, traction, and tread life. Here are a few popular options across different price tiers:

• Premium Option: Michelin X Line Energy Z (Steer) / XDN2 (Drive)

  • Price Tier: $$$$
  • Known for exceptional fuel efficiency, long tread life, and excellent handling. Michelin tires are a significant investment but often provide the best return in terms of performance and durability.

• Mid-Range Option: Bridgestone M703 (Steer) / M799 (Drive)

  • Price Tier: $$$
  • These Bridgestone options offer a great balance of performance and value. They are recognized for good wear characteristics and reliable traction in various conditions, making them a solid choice for many operations.

• Value Option: Yokohama 101ZL (Steer) / 703ZL (Drive)

  • Price Tier: $$
  • Yokohama provides durable and cost-effective solutions. Their heavy-duty truck tires offer good mileage and dependable performance, suitable for fleets looking to manage operational costs without sacrificing essential safety and reliability.

When to inflate to max load psi

For heavy-duty trucks like the Peterbilt 579, "max load psi" (often stamped on the tire sidewall) is critical, especially when operating at or near the tire's maximum rated load capacity. Unlike passenger vehicles, it's common and often necessary to inflate heavy-duty truck tires to higher pressures.

Always refer to your truck's door placard or owner's manual for the recommended cold tire inflation pressures for various loading conditions. The pressures listed on the placard are calculated by the vehicle manufacturer to provide optimal handling, braking, and tire life for the Gross Axle Weight Rating (GAWR).

You should inflate your tires to the higher end of the recommended pressure range, or even up to the maximum sidewall pressure, when:

• Operating at or near the maximum Gross Vehicle Weight (GVW) or Gross Combination Weight (GCW).
• Hauling maximum allowable loads on an individual axle.
• Preparing for long hauls where sustained high speeds and heavy loads will generate more heat.

Under-inflation can lead to excessive heat buildup, premature tire wear, reduced fuel economy, and a higher risk of tire failure. Over-inflation can cause a harsher ride, uneven wear (center of the tread), and a reduced contact patch. Proper inflation, based on actual load and manufacturer recommendations, is paramount for safety and efficiency.

Lug nut torque & pattern

Proper lug nut torque is crucial for maintaining wheel security on a heavy-duty truck like the Peterbilt 579.

• Lug Nut Torque: Typically between 450-500 ft-lbs (foot-pounds). Always use a calibrated torque wrench for accuracy.
• Bolt Pattern: 10-lug on a 285.75mm bolt circle diameter.
• Torque Pattern: The lug nuts should be tightened in a star or crisscross pattern to ensure even clamping force across the wheel hub. After initial tightening, it is highly recommended to re-torque the lug nuts after the first 50-100 miles of operation, and then periodically as part of routine maintenance.

Common tire issues for this vehicle

Heavy-duty trucks like the Peterbilt 579 can experience specific tire-related issues due to their demanding operational environment:

• Uneven Wear: Often caused by improper tire inflation, misaligned axles, worn suspension components, or aggressive driving. Steer tires can cup or feather, while drive tires might wear unevenly across the tread block.
• Hydroplaning: While not unique to the 579, the sheer weight and contact patch of truck tires can make hydroplaning a serious concern in wet conditions, especially with worn treads.
• Tire Blowouts: A significant risk for heavy-duty trucks, often caused by underinflation (leading to excessive heat), overloading, road hazards, or repeated impacts. Regular inspection and proper inflation are key preventative measures.
• Shoulder Wear: Common on steer tires if they are underinflated or if the truck consistently makes sharp turns at speed. Can also indicate alignment problems.
• Traction Loss: Especially with drive tires, in adverse weather conditions (snow, ice) or on loose surfaces if the incorrect tread pattern or worn tires are used.
• TPMS Malfunctions: While generally reliable, TPMS sensors can fail due to battery depletion, physical damage, or sensor disconnection. This can lead to incorrect pressure readings or system warnings.

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