2020 GMC Sierra 1500 Tire Size & Pressure Guide

Choosing the right tires and maintaining proper tire pressure is crucial for the performance, safety, and longevity of your 2020 GMC Sierra 1500. Whether you use your truck for daily commuting, heavy towing, or off-road adventures in the AT4 trim, this guide provides all the factory specifications you need to keep your Sierra rolling right.

Quick answer

• OEM tire size: 255/70R17, 265/65R18, 275/65R18, 275/60R20, or 275/50R22 (depending on trim)
• Recommended cold tire pressure: 35 to 38 PSI front/rear (check driver's side door jamb placard for your specific trim)
• Bolt pattern: 6x139.7mm (6x5.5")
• Wheel size: 17x8.0 to 22x9.0
• Load index/speed rating: Typically 112T to 115S (LT tires on AT4 trims may have higher E-load ratings like 123/120Q)
• Spare tire size: 255/80R17 or matching full-size spare for AT4/Denali
• TPMS frequency: 433 MHz

Tire sizes by trim

The 2020 GMC Sierra 1500 was offered in several distinct trims, ranging from the utilitarian Base to the luxurious Denali and off-road-ready AT4. Here are the factory tire sizes by trim level:

Recommended replacement tires

When it is time to replace the rubber on your Sierra 1500, you have several excellent options depending on your driving style and budget:

• Michelin Defender LTX M/S (Premium/Highway): The gold standard for light trucks. Exceptionally quiet, long tread life, and great wet weather traction. Best for highway and city drivers.
• BFGoodrich All-Terrain T/A KO2 (Premium/All-Terrain): Perfect for the AT4 or anyone taking their Sierra off-road. Severe snow rated (3PMSF) with incredibly tough sidewalls.
• Falken Wildpeak A/T3W (Mid-Tier/All-Terrain): An incredibly popular alternative to the KO2. It offers aggressive styling, excellent wet and snow traction, and a quieter ride than expected for an all-terrain tire.
• Cooper Discoverer HT3 (Mid-Tier/Highway): A solid, budget-friendly highway terrain tire that handles light towing and hauling with ease while keeping road noise to a minimum.

When to inflate to max load psi

While the 2020 GMC Sierra 1500 is a light-duty (half-ton) truck and doesn't require the extreme 80 PSI rear pressures seen in 2500/3500 HD models, payload still matters. Standard factory pressure (usually 35-38 PSI) is optimized for an unladen truck.

If you are maxing out your payload capacity (around 1,500–2,200 lbs depending on configuration) or towing a heavy trailer, you should increase the rear tire pressure closer to the tire's maximum cold pressure rating (found on the tire sidewall—often 44 PSI for standard load (SL) tires or up to 50-80 PSI if you have upgraded to LT tires). This reduces sidewall flex, lowers tire temperatures, and improves vehicle stability. Always reduce the pressure back to the door placard spec when empty to avoid a harsh ride and premature center-tread wear.

Lug nut torque & pattern

Proper wheel installation is a critical safety factor, especially on modern GM trucks.

• Bolt Pattern: 6x139.7mm (commonly referred to as 6x5.5")
• Lug Nut Torque: 140 ft-lbs
• Thread Size: M14 x 1.5

Tech Tip: Always use a calibrated torque wrench. Do not rely solely on an impact gun. Retorque the lug nuts after 50–100 miles of driving anytime a wheel is removed. 140 ft-lbs is higher than many older trucks, so ensuring you hit this specification is crucial to prevent wheel-off conditions or warped brake rotors.

Common tire issues for this vehicle

• Outer Edge Wear on Front Tires: The heavy front end of the Sierra (especially with the 3.0L Duramax or 6.2L V8) can cause premature shoulder wear if the vehicle is frequently cornered hard or if the alignment is slightly out of spec (excessive positive camber or toe-in). Regular rotations every 5,000–7,000 miles are highly recommended.
• TPMS Sensor Failure/Reset Issues: The 433 MHz TPMS sensors on these trucks require a dedicated TPMS relearn tool when rotating tires. If you rotate the tires without reprogramming the system, your dashboard will display incorrect tire pressure locations.
• Cupping on Off-Road Trims: AT4 models equipped with aggressive mud-terrain or all-terrain tires are susceptible to tire cupping if shock absorbers wear out or if rotations are neglected.

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