2015 Isuzu NQR — Tire Size & Pressure

As an ASE-certified master technician, I’ve serviced countless commercial medium-duty trucks. The 2015 Isuzu NQR is a staple for delivery, landscaping, and hauling fleets. Because this is a Class 5 commercial cab-over truck, proper tire maintenance, load ratings, and inflation are absolutely critical for safety and operational efficiency.

Below is your comprehensive guide to the tire sizes, pressures, and wheel specifications for the 2015 Isuzu NQR.

Quick Answer: 2015 Isuzu NQR Tire & Wheel Specs

• OEM Tire Size: 225/70R19.5 (Dual rear wheels)
• Recommended Cold Tire Pressure: 95 PSI Front / 95 PSI Rear (varies by upfit and exact load; always check the door placard)
• Bolt Pattern: 6x222.25mm (6 on 8.75")
• Wheel Size: 19.5" x 6.0"
• Load Index / Speed Rating: 128/126 L (Load Range F or G)
• Spare Tire Size: 225/70R19.5 (Full-size)
• TPMS Frequency: N/A (Most 2015 Isuzu NQR commercial chassis do not feature a factory light-duty TPMS; aftermarket systems are common)

Tire Sizes by Trim

The 2015 Isuzu NQR is typically sold as an incomplete chassis cab (Standard Cab or Crew Cab). Because it is a purpose-built commercial vehicle, tire sizes do not fluctuate between luxury trims like passenger cars.

Recommended Replacement Tires

When selecting tires for the Isuzu NQR, you must choose commercial-grade medium-duty tires capable of handling heavy payloads. Here are some of the most reliable options on the market:

1. Premium Tier: Michelin XZE
   • Type: All-Position Commercial
   • Why it’s great: Exceptional tread life, excellent handling, and a highly retreadable casing. It’s the gold standard for steer and drive axles on local delivery routes.
2. Mid-Tier: Goodyear G661 HSA
   • Type: High-Scrub All-Position
   • Why it’s great: Designed for urban environments with lots of curbing and tight turns. Offers great durability and scrub resistance at a moderate price point.
3. Budget Tier: Sailun S637
   • Type: Regional All-Position
   • Why it’s great: An incredibly popular budget-friendly commercial tire that punches well above its weight class in terms of longevity and load stability.

When to Inflate to Max Load PSI (Heavy Duty)

The 2015 Isuzu NQR has a Gross Vehicle Weight Rating (GVWR) of 17,950 lbs. If your truck is fully loaded to its maximum capacity, you will need to inflate your tires to their maximum rated cold pressure (often 110 PSI for Load Range G tires).

• Running Empty: If your box or flatbed is empty, running at 110 PSI will result in a harsh ride and premature center-tread wear. You can drop the pressure closer to 85-90 PSI for better traction and comfort.
• Running Loaded: When hauling heavy equipment or a fully loaded box, inflate the tires to the maximum pressure listed on the tire sidewall and the vehicle's B-pillar placard to prevent catastrophic sidewall blowout caused by excess heat buildup.

Always use a heavy-duty tire pressure gauge that reads up to at least 150 PSI.

Lug Nut Torque & Pattern

Commercial wheels require strict adherence to torque specs. Improper torque on dual rear wheels (DRW) can lead to wheel-off incidents.

• Bolt Pattern: 6x222.25mm
• Lug Nut Torque: 380 ft-lbs (500 Nm)
• Tightening Sequence: Always use a star/crisscross pattern.
• Note: It is standard commercial practice to re-torque the lug nuts after 50 to 100 miles of driving following a wheel removal.

Common Tire Issues for this Vehicle

1. Steer Axle Cupping: The front tires on cab-over trucks carry a significant amount of the unladen vehicle weight. Worn shock absorbers or slightly out-of-spec toe settings will cause aggressive cupping or river-wear on the front tires.
2. Dual Tire Mismatch: The rear duals must be exactly matched in size, brand, tread depth, and pressure. If one tire is slightly smaller (due to wear or under-inflation), the larger tire takes all the weight, leading to rapid wear and potential blowouts.
3. Curbing Damage: Because the NQR is heavily used in urban delivery, the outer rear tires and front steer tires frequently suffer from sidewall scrub damage against concrete curbs. Inspect sidewalls regularly for exposed steel cords.

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