2022 Peterbilt 579 — Tire Size & Pressure

Quick answer

• OEM Tire Size: 11R22.5 (steer and drive axles)
• Recommended Cold Tire Pressure (Door Placard): 100-110 psi (steer axle); 85-100 psi (drive axles), depending on load and tire brand recommendations.
• Bolt Pattern: 10-hole, 285.75mm bolt circle diameter (Budd Mount)
• Wheel Size: 22.5 x 8.25 inches (standard)
• Load Index/Speed Rating: Varies greatly by specific tire model. Common load indexes for steer tires are L/M (single, 7380 lbs/axle), and drive tires are G/H (dual, 6170 lbs/axle). Speed rating generally J (62 mph) or K (68 mph) for most commercial truck tires.
• Spare Tire Size: Typically full-size, matching the installed tire size (11R22.5).
• TPMS Frequency: 433 MHz (common for heavy-duty commercial vehicles)

Tire sizes by trim

For the 2022 Peterbilt 579, the 11R22.5 tire size is standard across most configurations and trims, including day cabs, sleepers, and various vocational setups. While specific tire brands and tread patterns will vary based on application (long haul, regional, vocational), the fundamental tire dimension often remains 11R22.5 for both steer and drive axles. Some specialized applications or custom orders might opt for different sizes, such as 295/75R22.5, which offers a slightly different profile and potentially different load characteristics.

Axle Type	Standard Size	Optional/Upgrade Size
Steer	11R22.5	295/75R22.5
Drive	11R22.5	295/75R22.5

Recommended replacement tires

HGVs like the Peterbilt 579 demand robust, reliable tires designed for heavy loads and continuous operation. When replacing tires, it's crucial to match or exceed the OEM specifications for load capacity and speed rating to maintain safety and performance. Here are some popular options:

• Michelin X Line Energy Z (Steer) / D (Drive): A premium choice known for excellent fuel economy and long tread life. These tires are designed for long-haul applications, offering reduced rolling resistance.
  • Price Tier: Premium
• Bridgestone M799 (Steer) / M770 (Drive): Another top-tier option, Bridgestone tires are renowned for durability and traction. The M799 is a popular steer tire offering good handling, while the M770 is a robust drive tire for various conditions.
  • Price Tier: Premium
• Goodyear G399 LHS (Steer) / G305 LHD (Drive): Goodyear offers reliable performance with good wear characteristics. These tires are often chosen for their balance of fuel efficiency, traction, and longevity in diverse applications.
  • Price Tier: Mid-Premium
• Continental Hybrid HS3 (Steer) / HD3 (Drive): Continental provides a strong balance of performance and value, known for strong casings for retreadability and good all-around performance in regional and long-haul operations.
  • Price Tier: Mid-Range

When selecting replacement tires, always consult with a tire professional and consider your specific application (e.g., long-haul, regional, construction, vocational) to ensure the best fit.

When to inflate to max load psi

For heavy-duty trucks like the Peterbilt 579, understanding tire pressure is critical for safety, tire longevity, and fuel efficiency. Unlike passenger vehicles, where a single recommended pressure is often sufficient, HD trucks often operate with varying loads. The "max load psi" (often stamped on the tire sidewall) represents the maximum cold inflation pressure a tire can hold to support its maximum rated load capacity. However, inflating to this pressure at all times is not always necessary or advisable.

You should inflate to max load psi when:

• Operating at or near the tire's maximum rated load capacity: If your truck is consistently carrying heavy loads that approach the tire's limits, inflating to the max load psi ensures the tire can safely support that weight and withstand the stresses involved.
• Operating at Gross Vehicle Weight Rating (GVWR) or Gross Combination Weight Rating (GCWR): When your truck and trailer (if applicable) are at their maximum legal weight limits, maximum inflation pressure is typically required for optimal stability and load distribution.

Consider these points:

• Under-inflation leads to excessive heat buildup, premature tire wear (especially on the shoulders), increased rolling resistance, and reduced fuel economy.
• Over-inflation can lead to a harsher ride, reduced traction due to a smaller contact patch, and accelerated wear in the center of the tread.
• Always refer to the tire manufacturer's load and inflation tables. These tables provide precise pressure recommendations based on the actual axle weight. Weighing your truck (fully loaded) is the best way to determine the correct inflation pressure for your specific operation.
• Check tire pressure cold. Tire pressure should always be checked when the tires are cold, meaning the truck has been stationary for at least three hours or has not been driven for more than a mile at moderate speed.

Lug nut torque & pattern

Proper lug nut torque is paramount for the safe operation of your Peterbilt 579. Incorrectly torqued lug nuts can lead to wheel stud failure, wheel detachment, and dangerous accidents. The 2022 Peterbilt 579 typically uses a 10-hole, 285.75mm bolt circle diameter pattern, often referred to as "Budd Mount" wheels.

• Lug Nut Torque: For standard 22.5-inch wheels on a Peterbilt 579, the recommended lug nut torque is typically 450-500 ft-lbs (610-678 Nm). It is critical to use a calibrated torque wrench designed for heavy-duty applications.
• Torquing Pattern: A star or criss-cross pattern should be followed to ensure even clamping force across the wheel hub. This prevents distortion of the wheel and ensures proper seating. After the initial tightening, it's recommended to re-check the torque after the first 50-100 miles of operation and periodically thereafter.

Common tire issues for this vehicle

Heavy-duty trucks like the Peterbilt 579 are subject to unique tire wear patterns and issues due to their operating conditions, loads, and extended mileage. Understanding these can help with proactive maintenance and longer tire life.

• Irregular Wear: This is a broad category but common. It includes:
  • Cupping/Scalloping: Often indicates worn suspension components, unbalanced tires, or improper inflation.
  • Feathering: Can be a sign of alignment issues, particularly on steer axles.
  • Shoulder Wear: Can be caused by under-inflation, sharp turning, or aggressive driving, especially on drive axles.
  • Center Wear: Typically a result of over-inflation.
• Road Hazards: Potholes, debris, and curbs are a constant threat, leading to punctures, sidewall damage, and impact breaks. Regular inspections for foreign objects and damage are crucial.
• Heat Buildup: Under-inflation or excessive speed under heavy loads can cause tires to overheat, leading to tread separation, blowouts, and premature failure. Maintaining correct pressure is the primary defense.
• Chemical Degradation: Exposure to oil, grease, fuel, and other chemicals common in trucking environments can degrade the tire's rubber compounds, leading to cracking and weakening.
• Age-Related Cracking: Even with good tread remaining, tires have a service life. Over time, UV exposure and natural rubber degradation can cause sidewall cracking, indicating a need for replacement regardless of tread depth.

Regular tire inspections by the driver and professional technicians are vital for identifying and addressing these issues early, preventing costly downtime and improving safety.

Need new tires? Find a trusted shop on Repairius.