2015 Peterbilt 579 Tire Size, Pressure & Torque Specs

As an ASE-certified master technician, I’ve seen countless Class 8 trucks roll through the bays, and the 2015 Peterbilt 579 is a frequent flyer. Built for aerodynamics and long-haul efficiency, the 579 relies heavily on proper tire selection and maintenance to maximize fuel economy and minimize blowout risks. Whether you are running a fleet or operating as an owner-operator, getting your tire specs right is crucial to your bottom line.

Here is your comprehensive guide to the tire, wheel, and pressure specifications for the 2015 Peterbilt 579.

Quick Answer: 2015 Peterbilt 579 Tire & Wheel Specs

• OEM Tire Size: 295/75R22.5, 11R22.5, or 285/75R24.5 (varies by spec and route)
• Recommended Cold Tire Pressure: Steer Axle: 105–110 PSI / Drive Axles: 95–100 PSI (Always check the driver's side door jamb placard for exact fleet spec)
• Bolt Pattern: 10-lug hub-piloted, 10x285.75mm (10x11.25")
• Wheel Size: 22.5" x 8.25" or 24.5" x 8.25"
• Load Index / Load Range: Load Range G (14-ply) or H (16-ply) / Steers typically require 149/146 (6,610+ lbs capacity); Drives typically 144/141. Speed Rating usually L (75 mph).
• Spare Tire Size: Typically not equipped from the factory (frame-mounted full-size spare optional)
• TPMS Frequency: 433 MHz (Often Bendix SmarTire system, if equipped)

Tire Sizes by Axle and Application

Unlike passenger vehicles that use "trims," Class 8 trucks like the Peterbilt 579 use different tire sizes based on their axle position (steer vs. drive) and their primary application (long haul, regional, or heavy haul).

Axle / Application	Common Tire Size	Wheel Size	Typical Load Range
Standard Long Haul (Steer)	295/75R22.5	22.5x8.25	H (16-ply)
Standard Long Haul (Drive)	295/75R22.5	22.5x8.25	G (14-ply) or H
Heavy/Regional (Steer)	11R22.5 or 11R24.5	22.5x8.25 / 24.5x8.25	H (16-ply)
Heavy/Regional (Drive)	11R22.5 or 11R24.5	22.5x8.25 / 24.5x8.25	H (16-ply)
Low-Pro Applications	285/75R24.5	24.5x8.25	G or H

Note: Always match dual drive tires exactly in brand, model, tread depth, and diameter to prevent differential wear and driveline stress.

Recommended Replacement Tires

When replacing tires on a 2015 Peterbilt 579, fuel efficiency (Low Rolling Resistance) and tread life are paramount. Here are top recommendations based on axle placement:

Steer Tires:

• Premium Tier: Michelin X Line Energy Z — Industry-leading tread life and fuel economy for long-haul routes.
• Mid-Tier: Bridgestone R213 Ecopia — Excellent irregular wear resistance and strong fuel savings.
• Value Tier: Yokohama 101ZL — Solid casing durability and predictable steering response at a lower price point.

Drive Tires (Closed Shoulder / Lug):

• Premium Tier: Michelin X Line Energy D — Exceptional traction and fuel efficiency for tandem axles.
• Mid-Tier: Goodyear Fuel Max LHD — Great balance of biting edges for winter traction and low rolling resistance.
• Value Tier: Firestone FD691 — A rugged, reliable workhorse tire for regional or mixed-use routes.

When to Inflate to Max Load PSI

Because the Peterbilt 579 is a Class 8 heavy-duty truck, tire pressure is heavily dictated by your axle weights.

• Steer Axles: Often run near maximum inflation (110–120 PSI for Load Range H) because the steer axle weight is relatively static (typically around 12,000 to 13,200 lbs) due to the heavy PACCAR or Cummins engine block.
• Drive Axles: Should be inflated to max load PSI (typically 100–105 PSI) only when you are pulling fully loaded trailers (tandem axles grossing 34,000 lbs). If you are deadheading (bobtailing) or running empty trailers for extended periods, running max PSI will cause harsh rides and rapid center-tread wear. Always consult your tire manufacturer's load/inflation tables.

Lug Nut Torque & Pattern

Proper wheel torque is a critical safety item on commercial trucks. Wheel-off incidents can be catastrophic.

• Bolt Pattern: 10x285.75mm (Hub-piloted)
• Lug Nut Torque: 450 – 500 lb-ft.
• Torque Sequence: Always use a star/cross pattern. Start at 12 o'clock, move to 6 o'clock, then 2 o'clock, 8 o'clock, etc.
• Tech Tip: Re-torque all lug nuts after the first 50 to 100 miles of driving following a wheel installation. Ensure hub and wheel mating surfaces are clean of rust and debris before mounting.

Common Tire Issues for this Vehicle

1. Rivering / Edge Wear on Steers: The aerodynamic setup of the 579 can sometimes lead to sensitive front-end alignment. If toe or camber is slightly out of spec, you will see rapid edge wear or "rivering" on the steer tires. Regular three-axle alignments are highly recommended.
2. Dual Mismatch: Drive tires must be matched within 1/4-inch in circumference. Mismatched duals drag the smaller tire, causing rapid scrubbing and generating excessive heat, which can lead to casing failure.
3. Cupping from Bad Shocks: Heavy hauling takes a toll on the front shock absorbers. If your 579's steer tires begin to cup or dish, check the shocks and kingpins immediately.

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