2024 Peterbilt 579 — Tire Size & Pressure

Quick answer

• OEM Tire Size: Varies significantly by configuration (steer, drive, and trailer axles)
• Recommended Cold Tire Pressure (Door Placard): Varies significantly; check your specific vehicle's door placard
• Bolt Pattern: 10-hole, 285.75mm bolt circle (standard heavy-duty truck)
• Wheel Size: 22.5" x 8.25" or 24.5" x 8.25" (common for steer and drive axles)
• Load Index/Speed Rating: Varies greatly; typically J (62 mph) or L (75 mph) speed ratings with high load indexes commensurate with heavy-duty use.
• Spare Tire Size: Not typically equipped with a "spare" in the conventional sense; usually, a service truck or roadside assistance is used for tire issues, or a spare wheel/tire assembly is carried if specified by the operator.
• TPMS Frequency: 433 MHz (common for heavy-duty trucks)

Tire sizes by trim

The Peterbilt 579 is a heavy-duty commercial truck, and tire sizes are highly customizable based on application, axle configuration (steer, drive, tag), and customer preference. There isn't a simple "trim" level that dictates tire size as with passenger vehicles. However, common configurations include:

Axle Position	Common Tire Sizes (Examples)
Steer Axle	295/75R22.5, 11R22.5, 315/80R22.5, 285/75R24.5
Drive Axle	295/75R22.5, 11R22.5, 285/75R24.5
Trailer Axle (if applicable)	295/75R22.5, 11R22.5, 285/75R24.5

It is crucial to consult your specific vehicle's specifications and door placard for the exact OEM tire sizes and recommended pressures for each axle.

Recommended replacement tires

When replacing tires on a Peterbilt 579, selection depends heavily on the application (e.g., long-haul, regional, vocational), terrain, and desired performance characteristics (e.g., fuel economy, traction, tread life). Here are a few popular options by type, not specific models, as selections vary:

• Long-Haul Steer Tires (Premium Fuel Economy): Designed for low rolling resistance and long tread life on highways. (Price Tier: $$$)
• All-Position Regional Tires (Durability & Versatility): Suitable for varying conditions and provide a balance of wear and traction. (Price Tier: $$)
• Drive Axle Traction Tires (Aggressive Grip): Feature deeper, more aggressive treads for enhanced traction in various weather conditions. (Price Tier: $$$)
• Trailer Tires (Free-Rolling & Durability): Optimized for free-rolling axles, focusing on durability and mile-per-volt. (Price Tier: $$)

Always ensure replacement tires match or exceed the original equipment's load index and speed rating for your specific axle position.

When to inflate to max load PSI

For heavy-duty trucks like the Peterbilt 579, tires should always be inflated to the cold tire pressure recommended on your vehicle's door placard for the given load. This recommended pressure is engineered to match the Gross Axle Weight Rating (GAWR) to ensure optimal tire performance, handling, and safety. There isn't a separate "max load PSI" to consider; rather, the placard pressure is derived from the maximum load the axle is designed to carry.

Never guess or rely on the maximum pressure stamped on the tire's sidewall. This is the maximum safe inflation pressure for the tire itself, not necessarily the correct pressure for your vehicle. Over-inflation or under-inflation can lead to premature wear, reduced fuel economy, poor handling, and increased risk of tire failure.

Regularly check tire pressures when the tires are cold (before driving) to maintain proper inflation.

Lug nut torque & pattern

The standard lug nut torque for a Peterbilt 579 (and most heavy-duty trucks with 10-hole, 285.75mm bolt circle wheels) is typically 450-500 ft-lbs (610-678 Nm). Always re-check your vehicle's specific service manual or manufacturer guidelines for the precise torque specification.

Tightening Pattern: A star or criss-cross pattern should always be used to ensure even clamping force across the wheel hub. This prevents wheel runout and ensures proper wheel retention.

1. Start with one lug nut.
2. Move directly across to the opposite lug nut.
3. Continue this criss-cross pattern until all lug nuts are snug.
4. Perform a final torque pass on all lug nuts in the same star pattern to the specified torque.

New wheels or tires, or after any wheel removal, should have their lug nuts re-torqued after the first 50-100 miles of operation to ensure they remain secure.

Common tire issues for this vehicle

Given the heavy-duty nature and constant operation of a Peterbilt 579, several tire issues are common:

• Uneven Wear: Often a result of improper inflation, misalignment, worn suspension components, or imbalanced tires. Steer axle tires may show feathering or shoulder wear, while drive axle tires can exhibit irregular wear patterns if not rotated or if there are driveline issues.
• Premature Wear: Can be caused by aggressive driving, overloading, high speeds, or improper tire selection for the application. Maintaining proper inflation and regular inspections can mitigate this.
• Tire Blowouts/Failures: Heavy loads, prolonged highway speeds, and road debris contribute to tire failures. Proper maintenance, including regular pressure checks and visual inspections for cuts or bulges, is critical.
• Cupping/Scalloping: Typically indicates worn shock absorbers or suspension components. This irregular wear pattern can lead to vibrations and reduced tire life.
• Road Hazard Damage: Punctures, cuts, and impact damage from potholes or debris are constant threats in commercial operations. Regular pre-trip inspections are essential.

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