2020 Kenworth T680 Tire Size, Pressure & Wheel Specs

As an ASE-certified master technician, I’ve seen my fair share of heavy-duty trucks roll through the bay. When it comes to Class 8 commercial vehicles like the 2020 Kenworth T680, getting your tire specs right isn't just about ride quality—it's about compliance, fuel economy, and absolute safety with up to 80,000 pounds gross combination weight (GCW) on the line.

Here is the comprehensive guide to the tire sizes, inflation pressures, and wheel specifications for your 2020 Kenworth T680.

Quick answer

• OEM Tire Size: 295/75R22.5 or 11R22.5 (Standard for steer and drive axles)
• Recommended Cold Tire Pressure: 105-110 PSI (Front/Steer), 95-100 PSI (Rear/Drive) Always verify with the door jamb VIN placard and axle weight limits.
• Bolt Pattern: 10-lug hub-piloted (10x285.75mm)
• Wheel Size: 22.5" x 8.25" (Standard) or 24.5" x 8.25" (Optional)
• Load Index / Speed Rating: Load Range G (14-ply) or H (16-ply) / Speed Rating L (75 mph) or M (81 mph)
• Spare Tire Size: Not typically equipped from the factory (full-size matching 295/75R22.5 if carried)
• TPMS Frequency: 433 MHz (If equipped with Bendix SmarTire or similar factory/aftermarket systems)

Tire sizes by configuration

While passenger vehicles have trims, Class 8 trucks like the T680 are highly customizable based on the application (linehaul, regional, heavy haul). Here are the most common configurations rolling out of the Kenworth factory:

Recommended replacement tires

When replacing tires on a commercial rig, you want to focus on rolling resistance for fuel economy and treadwear for cost per mile. Here are excellent choices for the T680:

1. Michelin X Line Energy Z (Steer) / D (Drive)
   • Price Tier: Premium
   • Why: Exceptional fuel efficiency and verified SmartWay technology. These offer an incredibly low rolling resistance and long, even wear for linehaul applications.
2. Bridgestone R213 Ecopia (Steer) / M713 Ecopia (Drive)
   • Price Tier: Premium
   • Why: Fantastic directional stability and a highly advanced tread compound that resists irregular wear. A great investment for long-haul fleets.
3. Goodyear Endurance LHS (Steer) / LHD (Drive)
   • Price Tier: Mid-High
   • Why: Robust casing and reliable all-weather grip. Known for having one of the best retreadabilities in the market, saving you money in the long term.

When to inflate to max load psi

Because the Kenworth T680 is a heavy-duty Class 8 truck, tire pressure management is directly tied to the weight you are hauling. The max cold pressure stamped on a Load Range H commercial tire is typically 120 PSI.

You should inflate to max load PSI when:

• You are loading the specific axle to its maximum gross axle weight rating (GAWR). For example, if your front steer axle is rated for 12,500 lbs, or up to 13,200 lbs, you must inflate the steer tires closer to 110-120 PSI to safely carry the weight without excessive sidewall flex and heat buildup.
• Caution: Unnecessarily running max PSI on an empty or lightly loaded truck will cause a harsh ride, premature center tread wear, and reduced traction. Always consult a commercial tire load/inflation table from your tire manufacturer (like Michelin or Bridgestone) and adjust based on your actual scale weights.

Lug nut torque & pattern

Commercial wheel ends require strict maintenance to prevent wheel-offs.

• Bolt Pattern: 10x285.75mm (Hub-piloted)
• Lug Nut Torque Specs: 450 – 500 ft-lbs.
• Procedure: Wheels must be mounted cleanly with a few drops of oil on the stud threads and between the nut and integral washer (never oil the mating faces of the wheel/hub). Always use a star pattern when torquing, and re-torque after the first 50 to 100 miles of operation following a wheel removal.

Common tire issues for this vehicle

• Rivering/Cupping on Steer Tires: The T680’s aerodynamic design puts specific stresses on steer tires. If shocks are worn, or alignment (toe/caster) is slightly out, you will quickly see river wear or cupping on the outer ribs of your steer tires.
• Irregular Wear on Drives: Mismatched dual tire pressures are the number one killer of drive tires. Even a 5 PSI difference between duals means the smaller (under-inflated) tire is being dragged by the larger tire, leading to rapid, scrubbed wear.
• Valve Stem Leaks: Because commercial tires run at 100+ PSI, standard valve cores can fail if debris gets inside. Always run metal flow-through valve caps.

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