2025 Kenworth T680 — Tire Size & Pressure

Quick Answero - OEM Tire Size (Steer Axle): 295/75R22.5, 11R22.5, 315/80R22.5 (varies by spec)o - OEM Tire Size (Drive Axle): 295/75R22.5, 11R22.5, 445/50R22.5 (Super Singles - varies by spec)o - Recommended Cold Tire Pressure (Steer Axle): 100-120 psi (check door placard/tire sidewall for exact spec)o - Recommended Cold Tire Pressure (Drive Axle): 85-105 psi (check door placard/tire sidewall for exact spec)o - Bolt Pattern: 10-hole, 285.75mm bolt circle (standard for heavy-duty trucks)o - Wheel Size: 22.5 x 8.25", 22.5 x 9.00", 22.5 x 14.00" (Super Single)o - Load Index/Speed Rating: Varies significantly by tire and application. Consult tire sidewall. Common speed ratings include L (75 mph) and M (81 mph).o - Spare Tire Size: Typically full-size match for drive axle.o - TPMS Frequency: 433 MHz (common for heavy-duty applications)

Tire Sizes by Trim

The Kenworth T680 is a highly configurable heavy-duty truck, and tire sizes are rarely tied to specific "trims" in the same way they are for passenger vehicles. Instead, tire specifications are determined by the intended application, gross vehicle weight rating (GVWR), gross combination weight rating (GCWR), and customer preferences. Below are common tire sizes found on various T680 configurations:

Note: "R" denotes radial construction. Heavy-duty truck tires often use a simplified nomenclature (e.g., 11R22.5) where 11 refers to the section width in inches and 22.5 to the wheel diameter in inches.

Recommended Replacement Tires

When replacing tires on your Kenworth T680, it's crucial to select tires that meet or exceed the original equipment specifications for load capacity, speed rating, and application (e.g., long-haul, regional, vocational). Always consult your truck's door placard and the tire manufacturer's specifications.

Here are some popular and highly-regarded replacement tire options for the Kenworth T680, categorized by price tier:

• Premium Tier:
  • Michelin X Line Energy Z (Steer): Known for excellent fuel efficiency and long tread life. (Price: $$$$)
  • Goodyear Fuel Max LHD G505D (Drive): Designed for superior fuel economy and traction in long-haul applications. (Price: $$$$)
• Mid-Range Tier:
  • Bridgestone M760 Ecopia (Drive): Offers a good balance of fuel efficiency, traction, and durability. (Price: $$$)
  • Continental Hybrid HS3 (Steer): A versatile steer tire providing good handling and wear characteristics. (Price: $$$)
• Value Tier:
  • Sumitomo ST719 (Steer/Drive): A reliable option offering solid performance for budget-conscious operators. (Price: $$)

When to Inflate to Max Load PSI

For heavy-duty trucks like the Kenworth T680, "max load PSI" (the maximum cold inflation pressure marked on the tire sidewall) is critical. You should inflate your tires to the maximum load PSI only when operating at or near the tire's maximum rated load capacity.

However, it is more common and generally recommended to inflate your tires to the pressure specified on your truck's door placard for your specific axle loads. This provides the optimal balance of ride comfort, tire wear, and fuel efficiency for your typical operating conditions. Over-inflating for lighter loads can lead to a harsher ride, uneven tire wear (center wear), and reduced traction. Under-inflating for heavy loads can cause excessive heat buildup, premature tire failure, and reduced fuel economy.

Always use a high-quality tire pressure gauge designed for commercial vehicle tires and check pressures when the tires are cold (before driving).

Lug Nut Torque & Pattern

The Kenworth T680, like most heavy-duty trucks, typically uses a 10-hole wheel with a 285.75mm bolt circle. The lug nuts are critical for wheel retention and safety.

• Lug Nut Torque: 450-500 ft-lbs (610-678 Nm). Always use a calibrated torque wrench specifically designed for heavy-duty applications. Never rely on an impact gun alone for final torque.
• Torquing Pattern: For optimal wheel seating and even pressure, lug nuts should be tightened in a star pattern (crisscross) sequence. This ensures the wheel is properly seated against the hub and prevents uneven stress on the studs.

After initial installation or a wheel removal, re-torque the lug nuts after 50-100 miles of operation. This is crucial to account for any settling of the wheel components.

Common Tire Issues for this Vehicle

While the Kenworth T680 is a robust truck, common tire issues can arise, often related to maintenance, loading, or alignment:

• Uneven Wear: Often indicative of improper inflation pressure, misalignment (toe, camber, caster), or worn steering/suspension components. Cupping or feathering wear patterns are common indicators.
• Blowouts/Punctures: Can be caused by road hazards, underinflation leading to excessive heat, or overloaded tires. Regular pre-trip inspections can help identify potential issues like cuts or bulges.
• Tire Hydroplaning: More prevalent with worn tread depth, especially on steer tires, which can compromise steering control in wet conditions.
• Vibrations: Can stem from unbalanced tires, bent wheels, or worn wheel bearings. Prompt diagnosis is important to prevent further damage.
• TPMS Malfunctions: Sensor failures, low battery, or improper programming can lead to false warnings. Ensure your TPMS system is functioning correctly to monitor tire pressures effectively.

Regular tire rotations (for drive axles), professional alignments, consistent pressure checks, and thorough pre-trip inspections are your best defenses against these issues.

Need new tires? Find a trusted shop on Repairius.