2018 GMC Sierra 2500HD Tire Size & Pressure Specs

As an ASE-certified master technician, I know that keeping a heavy-duty truck like the 2018 GMC Sierra 2500HD safely on the road starts where the rubber meets the asphalt. Whether you use your 2500HD for daily commuting, heavy towing, or hauling payload on a job site, having the correct tire size, load rating, and tire pressure is critical for vehicle stability and tire longevity.

Below is your comprehensive guide to the 2018 GMC Sierra 2500HD tire and wheel specifications.

Quick answer

Here are the most critical tire and wheel specs for the 2018 GMC Sierra 2500HD at a glance:

• OEM Tire Sizes: LT245/75R17, LT265/70R18, or LT265/60R20
• Recommended Cold Tire Pressure: 60 PSI Front / 70 to 80 PSI Rear (Check driver's side door jamb placard for exact pressures for your specific configuration)
• Bolt Pattern: 8x180 mm
• Wheel Sizes: 17x7.5, 18x8.0, or 20x8.5 (Offset is typically +44mm)
• Load Index / Speed Rating: 121/118S to 123/120R (Must be Load Range E / 10-ply rated)
• Spare Tire Size: Usually matches the factory wheel diameter, or an LT265/70R18 on a steel wheel.
• TPMS Frequency: 315 MHz

Tire sizes by trim

Depending on the trim level and optional packages selected, your 2500HD will come equipped with one of the following setups. Always check your tire sidewall to confirm before purchasing replacements.

Recommended replacement tires

Because the Sierra 2500HD is a heavy-duty pickup, it is absolutely essential to buy LT-metric (Light Truck) tires with a Load Range E. Do not put standard P-metric (Passenger) tires on this truck. Here are a few top-rated options:

• Premium / Best Overall: Michelin Defender LTX M/S – Exceptional highway ride quality, long tread life, and great wet traction.
• All-Terrain / Off-Road: BFGoodrich All-Terrain T/A KO2 – Tough sidewalls, aggressive looks, and Severe Snow Rated (3PMSF). Perfect if your job site is muddy or snowy.
• Mid-Tier / Value: Falken Wildpeak A/T3W – Excellent balance of on-road manners, off-road durability, and competitive pricing.
• Budget-Friendly Commercial: Firestone Transforce HT2 – A solid, no-nonsense commercial highway tire that handles heavy loads reliably.

When to inflate to max load psi

For the 2018 GMC Sierra 2500HD, the rear tires are often rated for up to 80 PSI (max load pressure for a Load Range E tire).

You should only inflate the rear tires to this maximum 80 PSI when you are carrying a heavy payload in the bed or towing a heavy trailer with a high tongue weight. Inflating to the max PSI ensures the tire's sidewalls have the rigidity needed to handle the load without overheating or causing a blowout.

When you are driving unloaded (empty bed, no trailer), running 80 PSI in the rear will result in an incredibly harsh ride and premature center-tread wear. When unloaded, drop the rear tires down to the standard unloaded pressure listed on your door placard (usually around 60 to 70 PSI, depending on the exact truck configuration).

Lug nut torque & pattern

Proper wheel torque is vital on an HD truck. Uneven or improper torque can lead to warped brake rotors or, in severe cases, the wheel coming loose.

• Bolt Pattern: 8x180 mm (GM changed to this heavy-duty 8-lug pattern in 2011; older 8x165.1 wheels will not fit).
• Lug Nut Torque: 140 lb-ft (190 Nm).
• ** tightening sequence:** Always use a star/cross pattern to ensure the wheel sits flush against the hub.

Tech tip: Always re-torque your lug nuts after the first 50 to 100 miles of driving following a wheel installation or tire rotation.

Common tire issues for this vehicle

1. Cupping and Chopping: The heavy front end of the Sierra 2500HD (especially if equipped with the Duramax Diesel engine) puts immense stress on the front tires. Failing to rotate your tires every 5,000 to 7,000 miles often leads to cupping and a very loud, vibrating ride.
2. TPMS Sensor Failures: The 315 MHz sensors in these trucks have internal batteries that typically last 5–7 years. A 2018 model is right in the window where these sensors may begin dying. If your dash light flashes for 60 seconds and then stays solid, you likely have a dead sensor.
3. Worn Idler/Pitman Arms: While not a tire issue directly, GM's heavy-duty independent front suspension (IFS) wears through steering components under heavy use. If your tires are wearing unevenly on the inner or outer edges despite a good alignment, have a mechanic inspect the idler and pitman arms for excessive play.

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