The 2020 GMC Trucks Sierra 3500 HD sits in the modern heavy-duty pickup segment where towing, payload, and off-pavement confidence matter just as much as day-to-day road manners. In this generation, the Sierra 3500 HD combined contemporary HD truck capability with distinct trim and wheel packages that changed the tire decision more than styling alone. This model uses three primary radial tire sizes: 235/80R17, 275/70R18, and 275/65R20. Available choices here center less on bias-ply-versus-radial questions and more on confirming the exact sub-model, wheel diameter, sidewall presentation, and load-oriented tire specifications. Getting the size right starts with identifying whether the truck is DRW or a single-rear-wheel trim with 18-inch or 20-inch wheels.
Which Tire Size Is Right for The 2020 GMC Trucks Sierra 3500 HD
Three primary tire sizes apply to the 2020 GMC Trucks Sierra 3500 HD, and the right one depends on the exact sub-model and wheel diameter. All three are radial sizes, but they span 17-inch, 18-inch, and 20-inch rims, so confirming the truck's current wheel setup comes first. Once that is settled, the real comparison is between the correct size's load-oriented specifications, sidewall treatment, and intended use.
Fit(s): (DRW), Denali (DRW), SLE (DRW), and SLT (DRW)
Construction: Radial|Rim: 17 in
235/80R17 is a metric radial size with a 235-millimeter nominal section width, an 80-series aspect ratio, and fitment for a 17-inch rim. On the 2020 GMC Trucks Sierra 3500 HD, this size is tied to DRW configurations, making it a fitment that should be matched carefully to the truck's exact rear-wheel setup. In the available selection, it appears as a BFGoodrich All-Terrain T/A KO2 with an RBL sidewall and heavy-duty load capability. This size is the one to evaluate when the truck uses 17-inch dual-rear-wheel hardware and the buyer wants to stay within that specific wheel and tire package.
275/65R20 is a metric radial size that uses a 275-millimeter nominal section width, a 65-series profile, and a 20-inch rim diameter. On this Sierra 3500 HD, it appears on certain single-rear-wheel trims rather than across the full model range, so it should be matched to the truck's actual trim and wheel package. The current product choice is a BFGoodrich All-Terrain T/A KO2 with an RBL sidewall, giving it a modern all-terrain look on a larger wheel. This size makes sense when the truck already carries 20-inch wheels and the goal is to preserve that stance and fitment direction.
275/70R18 is a metric radial size with a 275-millimeter nominal section width, a 70-series aspect ratio, and fitment for an 18-inch rim. For the 2020 GMC Trucks Sierra 3500 HD, this size is used on several single-rear-wheel trims and represents a different wheel package from the 20-inch option. It is available here as a BFGoodrich All-Terrain T/A KO2 with raised white letter styling, which gives the truck a more traditional all-terrain sidewall presentation than the black-letter alternatives. This is the size to verify when the truck runs 18-inch wheels and the buyer wants to keep the existing tire and wheel relationship in the proper range.
Tire fitment on the 2020 GMC Trucks Sierra 3500 HD is not the same across every sub-model. DRW trucks use a different size from single-rear-wheel trims, and several AT4, SLE, and SLT configurations can fall into either 18-inch or 20-inch wheel packages, so confirming the exact sub-model and wheel setup matters before choosing a tire.
1
2020 GMC Trucks Sierra 3500 HD (DRW)
The 2020 GMC Trucks Sierra 3500 HD (DRW) uses the 235/80R17 radial size rather than the wider 18-inch and 20-inch single-rear-wheel fitments. Tire selection here should stay focused on the truck's 17-inch dual-rear-wheel setup, load needs, and wheel compatibility.
The 2020 GMC Trucks Sierra 3500 HD AT4 can use either 275/65R20 or 275/70R18, so tire choice depends on the exact wheel package on the truck. That makes wheel-diameter confirmation the first step before comparing sidewall style, rim-width range, or other tire details.
The 2020 GMC Trucks Sierra 3500 HD Base uses the 275/70R18 radial size. Tire selection is straightforward once the 18-inch wheel is confirmed, and the decision then shifts to the tire's sidewall presentation and other product-level specifications.
The 2020 GMC Trucks Sierra 3500 HD Denali uses the 275/65R20 radial size. That keeps the focus on matching the truck's 20-inch wheel package and checking the tire's rim-width compatibility and load-oriented specifications before replacement.
The 2020 GMC Trucks Sierra 3500 HD Denali (DRW) uses the 235/80R17 radial size associated with dual-rear-wheel configurations. Tire selection should center on maintaining the correct 17-inch DRW fitment rather than comparing it to the larger single-rear-wheel sizes.
The 2020 GMC Trucks Sierra 3500 HD SLE can use either 275/65R20 or 275/70R18, depending on the wheel setup. Before selecting a tire, it is important to confirm whether the truck has 18-inch or 20-inch wheels so the replacement stays aligned with the actual configuration.
The 2020 GMC Trucks Sierra 3500 HD SLE (DRW) uses the 235/80R17 radial size. Buyers replacing tires on this sub-model should treat the DRW wheel package as the key fitment point and avoid assuming the single-rear-wheel sizes apply.
The 2020 GMC Trucks Sierra 3500 HD SLT can use either 275/65R20 or 275/70R18. That means the correct tire depends on the truck's existing wheel diameter first, with product selection coming afterward once the 18-inch or 20-inch setup is confirmed.
The 2020 GMC Trucks Sierra 3500 HD SLT (DRW) uses the 235/80R17 radial size. For this sub-model, the priority is matching the 17-inch DRW arrangement and checking the replacement tire against the truck's intended work and road-use demands.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 2020 GMC Trucks Sierra 3500 HD Tires for Sale
Available tires for the 2020 GMC Trucks Sierra 3500 HD center on BFGoodrich All-Terrain T/A KO2 radials in the three correct sizes. Comparison points include 17-inch, 18-inch, or 20-inch fitment, RBL versus RWL sidewall styling, and the rim-width and load-capacity specifications tied to each size.
Owners researching 2020 GMC Trucks Sierra 3500 HD tires usually need to sort out the correct size by sub-model, wheel diameter, and DRW status first. The questions below focus on fitment, radial tire selection, appearance differences, and the checks worth making before road use.
Tire Size & Fitment
What tire size fits a 2020 GMC Trucks Sierra 3500 HD?
The 2020 GMC Trucks Sierra 3500 HD uses three primary tire sizes: 235/80R17, 275/70R18, and 275/65R20. The correct one depends on the truck's exact configuration, with DRW models using 235/80R17 and single-rear-wheel trims using either 275/70R18 or 275/65R20 depending on the wheel package.
The most important next step is confirming whether the truck is DRW or single rear wheel and then checking the actual wheel diameter on the vehicle. A Sierra 3500 HD with changed wheels, aftermarket packages, or prior tire substitutions should be measured and inspected before replacement so the new tire matches the real setup rather than the trim name alone.
What size rim does a 2020 GMC Trucks Sierra 3500 HD use?
A 2020 GMC Trucks Sierra 3500 HD can use 17-inch, 18-inch, or 20-inch rims depending on the sub-model and tire size. The 235/80R17 fitment uses a 17-inch rim, the 275/70R18 fitment uses an 18-inch rim, and the 275/65R20 fitment uses a 20-inch rim.
That makes wheel-diameter confirmation essential before ordering any replacement tire. Even within the same model line, trims such as AT4, SLE, and SLT can appear with different wheel packages, and DRW trucks use a separate 17-inch setup. Reading the tire sidewall and checking the wheel itself is the safest way to avoid choosing the wrong diameter.
Do all 2020 GMC Trucks Sierra 3500 HD sub-models use the same tire size?
No, 2020 GMC Trucks Sierra 3500 HD sub-models do not all use the same tire size. DRW versions use 235/80R17, the Base uses 275/70R18, the Denali uses 275/65R20, and AT4, SLE, and SLT can use either 275/70R18 or 275/65R20 depending on their wheel package.
That variation means the trim badge alone is not always enough to choose a tire. It helps to confirm the exact sub-model, determine whether the truck is dual rear wheel, and read the existing tire size on the truck now. That extra check matters even more if the Sierra has replacement wheels or a non-stock suspension setup.
Choosing the Right Tire
What should I consider when choosing a tire for a 2020 GMC Trucks Sierra 3500 HD?
Start with the correct primary size for the truck's actual setup: 235/80R17 for DRW models, or 275/70R18 and 275/65R20 for certain single-rear-wheel trims. From there, compare the tire's load capacity, rim-width range, sidewall treatment, and whether the tread style suits the way the Sierra 3500 HD is used.
A heavy-duty pickup often sees very different duty cycles, from unloaded road driving to towing and work use, so the tire should match both the truck's wheel package and its intended role. It is also worth checking whether the current wheels are original size, since a previous owner may have changed the wheel diameter without changing the trim designation.
What sidewall styles are available for 2020 GMC Trucks Sierra 3500 HD tires?
The available sidewall styles for the 2020 GMC Trucks Sierra 3500 HD include RBL and RWL, depending on the tire size. The 235/80R17 and 275/65R20 BFGoodrich All-Terrain T/A KO2 options use RBL styling, while the 275/70R18 option uses RWL styling.
That difference mainly affects appearance rather than basic fitment, but it can matter if the truck's look is part of the decision. A black-letter sidewall gives a more understated presentation, while raised white letters create a more traditional all-terrain visual. Sidewall style should be chosen only after confirming the correct size and wheel diameter for the truck.
What brands offer tires for the 2020 GMC Trucks Sierra 3500 HD?
The available tires for these 2020 GMC Trucks Sierra 3500 HD fitments are from BFGoodrich. Across the supported sizes, the product line is the All-Terrain T/A KO2, so the main comparison is less about brand switching and more about selecting the correct size, rim-width compatibility, load figure, and sidewall style.
That makes sub-model verification especially important, because the choice is really between the right 17-inch, 18-inch, or 20-inch fitment rather than between several competing brands. Once the size is confirmed, the buyer can compare the specific KO2 tire details that matter most for the truck's working use, road use, and appearance.
Restoration & Appearance
Which tire should I choose for a period-style 2020 GMC Trucks Sierra 3500 HD?
A period-style choice for a 2020 GMC Trucks Sierra 3500 HD starts with keeping the truck in its correct original-size family for the exact sub-model and wheel package. For this model year, that means staying with the proper radial size first, whether it is 235/80R17, 275/70R18, or 275/65R20.
Because this is a modern heavy-duty truck, appearance is influenced more by wheel diameter and sidewall treatment than by vintage construction choices. An owner trying to preserve the truck's intended look should confirm the existing wheel package and then decide whether RBL or RWL presentation better matches the truck's trim level and visual character.
How does tire construction affect the appearance of a restored 2020 GMC Trucks Sierra 3500 HD?
On a 2020 GMC Trucks Sierra 3500 HD, construction is straightforward because the primary fitments are radial. That means the visual differences come less from bias-ply-versus-radial shape and more from the correct size, the wheel diameter, and whether the tire uses an RBL or RWL sidewall treatment.
For a clean restoration-oriented presentation, maintaining the proper relationship between tire size and wheel package matters more than trying to change construction type. A truck sitting on the wrong diameter wheel or an incorrect sidewall style can look noticeably off, even when the tire is close in overall proportions. The best starting point is always the correct fitment for the exact sub-model.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2020 GMC Trucks Sierra 3500 HD?
Yes, modifications can affect tire fitment on a 2020 GMC Trucks Sierra 3500 HD. Wheel changes, suspension lifts or lowering, altered offsets, aftermarket fender parts, and prior tire substitutions can all change how a 235/80R17, 275/70R18, or 275/65R20 tire sits and clears the truck.
That matters even when the truck still wears a familiar trim badge, because the current setup may no longer match the original wheel package. A replacement should be checked against the actual wheel diameter and width, as well as steering, suspension, and body clearance. Dual-rear-wheel trucks deserve extra attention so the tire choice stays appropriate to that specific arrangement.
What should I inspect before driving a 2020 GMC Trucks Sierra 3500 HD on new tires?
Before driving a 2020 GMC Trucks Sierra 3500 HD on new tires, inspect wheel condition, confirm the tire size matches the truck's actual setup, and verify inflation is set appropriately for the tire and intended use. It also helps to look for any signs of uneven wear, suspension looseness, or rubbing points left by the previous tires.
A short road test should follow, with attention to steering response, clearance at full lock, and any contact under load or suspension movement. Heavy-duty trucks can hide fitment problems until they are turning, loaded, or on uneven surfaces, so it is smart to recheck the tires after the first drive for scuffing, air loss, or unusual wear patterns.
How often should tires on a 2020 GMC Trucks Sierra 3500 HD be inspected?
Tires on a 2020 GMC Trucks Sierra 3500 HD should be inspected regularly, not just at long service intervals. A quick check for air pressure, tread condition, cuts, bulges, cracking, and uneven wear is worthwhile before routine use, and a closer inspection is smart before towing, hauling, or taking the truck on a longer trip.
Consistent inspection matters because heavy-duty pickups place real demands on their tires, especially when load conditions change. It is also useful to watch for signs that the wheel alignment, suspension, or wheel hardware may need attention. Catching a pressure loss or wear pattern early can prevent a small issue from turning into a much larger road-use problem.
