The 2020 GMC Trucks Sierra 2500 HD sits in the modern heavy-duty pickup class, where towing, payload, off-pavement use, and daily road manners all matter. Buyers looking at this truck usually need more than a simple size lookup, because trim level and wheel package change the fitment. This Sierra 2500 HD uses radial tires in four primary sizes: 245/75R17, 265/70R17, 275/70R18, and 275/65R20. Available choices here center on BFGoodrich All-Terrain T/A KO2 products, with RWL and RBL sidewall presentations depending on size. The right pick starts with confirming the exact sub-model and wheel diameter, then matching load capacity, rim-width compatibility, and intended truck use.
Which Tire Size Is Right for The 2020 GMC Trucks Sierra 2500 HD
Four primary tire sizes apply to the 2020 GMC Trucks Sierra 2500 HD, and they vary by sub-model and wheel package. The first step is confirming the exact trim and rim diameter, since this truck uses 17-inch, 18-inch, and 20-inch wheel fitments. Once that is settled, the decision shifts to the right radial size, load specification, and sidewall style for the way the truck is equipped and used.
275/65R20 is a modern metric radial size: 275 is the nominal section width in millimeters, 65 is the aspect ratio, R identifies radial construction, and 20 is the rim diameter in inches. On the 2020 GMC Trucks Sierra 2500 HD, this size belongs to trucks equipped with a 20-inch wheel setup. In this fitment, BFGoodrich offers the All-Terrain T/A KO2 with an RBL sidewall treatment and a 7.5- to 9.5-inch rim-width range. It is the size to evaluate when the truck carries the larger-wheel package and you want to preserve the intended wheel-to-tire proportion.
275/70R18 follows the same modern metric radial format, with a 275-millimeter nominal width, a 70-series profile, radial construction, and an 18-inch rim. For the 2020 GMC Trucks Sierra 2500 HD, this size serves trims that use 18-inch wheels and gives a tall, heavy-duty truck tire profile. The available BFGoodrich All-Terrain T/A KO2 in this size uses an RWL sidewall and fits a 7.0- to 9.0-inch rim-width range. This is the size to compare when your truck is built around the 18-inch wheel package and you want to stay with that wheel diameter.
245/75R17 is a metric radial size with a 245-millimeter nominal width, a 75-series profile, and fitment on a 17-inch rim. On the 2020 GMC Trucks Sierra 2500 HD, it appears on certain 17-inch wheel applications and carries a narrower section width than the other primary sizes used on this truck. The BFGoodrich All-Terrain T/A KO2 offered here uses an RWL sidewall and calls for a 6.5- to 7.5-inch rim-width range. It is the right size to examine when your truck has the narrower 17-inch wheel setup rather than the wider 17-inch alternative.
265/70R17 is another modern metric radial size, combining a 265-millimeter nominal width, a 70-series profile, radial construction, and a 17-inch rim diameter. For the 2020 GMC Trucks Sierra 2500 HD, it is the second 17-inch-wheel fitment, so wheel diameter alone is not enough to choose between this size and 245/75R17. BFGoodrich All-Terrain T/A KO2 options in this size use an RWL sidewall and share a 7.0- to 9.0-inch rim-width range, with different load specifications available. This size deserves a closer look when the truck uses a 17-inch wheel but requires the wider of the two 17-inch tire fitments.
Sub-model fitment matters on the 2020 GMC Trucks Sierra 2500 HD because tire size changes across the AT4, Base, Denali, SLE, and SLT trims. Before choosing a tire, confirm the exact trim and wheel package so the size, rim diameter, and load specification stay aligned with the truck’s actual setup.
1
2020 GMC Trucks Sierra 2500 HD AT4
The 2020 GMC Trucks Sierra 2500 HD AT4 uses either 275/65R20 or 275/70R18 radial tires, depending on wheel configuration. That means the first decision is confirming whether the truck has 20-inch or 18-inch wheels before comparing sidewall style, load specification, and product details.
The 2020 GMC Trucks Sierra 2500 HD Base spans three radial tire sizes, so tire selection is tied closely to the truck’s actual wheel package. A Base truck owner should verify both rim diameter and the specific 17-inch or 18-inch size before choosing among available all-terrain options.
The 2020 GMC Trucks Sierra 2500 HD Denali uses the 275/65R20 radial fitment. For this trim, the choice is less about multiple primary sizes and more about confirming the 20-inch wheel setup, then reviewing load rating, rim-width compatibility, and sidewall presentation.
The 2020 GMC Trucks Sierra 2500 HD SLE has the broadest fitment spread, covering 17-inch, 18-inch, and 20-inch radial tire sizes. On an SLE, accurate tire selection starts with the truck’s actual wheels, since trim name alone does not narrow the fitment to one size.
The 2020 GMC Trucks Sierra 2500 HD SLT uses either 275/65R20 or 275/70R18 radial tires. For SLT owners, the practical step is verifying wheel diameter first, then choosing the tire that matches the truck’s installed wheel package and intended service.
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 2500 HD Tires for Sale
Available Sierra 2500 HD tire choices center on BFGoodrich All-Terrain T/A KO2 products across the four primary radial sizes. Comparison points include 17-, 18-, and 20-inch fitments, RWL or RBL sidewall presentation, rim-width requirements, and different load specifications in 265/70R17.
These Sierra 2500 HD FAQs focus on the size differences between trims, the 17-, 18-, and 20-inch wheel fitments, product-selection details, and the maintenance checks that matter before road use or heavier truck duty.
Tire Size & Fitment
What tire size fits a 2020 GMC Trucks Sierra 2500 HD?
The 2020 GMC Trucks Sierra 2500 HD uses four primary radial tire sizes: 245/75R17, 265/70R17, 275/70R18, and 275/65R20. The correct size depends on the truck’s sub-model and wheel package, so there is not one universal fitment across every Sierra 2500 HD configuration.
A quick look at the sidewall on the truck is often the easiest starting point, but wheel diameter should still be confirmed before replacing anything. The Sierra 2500 HD uses both 17-inch fitments as well as 18-inch and 20-inch fitments, so matching the exact size already on the truck helps avoid wheel mismatch, clearance issues, and load-specification mistakes.
What size rim does a 2020 GMC Trucks Sierra 2500 HD use?
Rim diameter on the 2020 GMC Trucks Sierra 2500 HD can be 17, 18, or 20 inches, depending on trim and wheel package. The tire sizes align with those wheel diameters: 245/75R17 and 265/70R17 use 17-inch rims, 275/70R18 uses an 18-inch rim, and 275/65R20 uses a 20-inch rim.
That rim measurement is the first number to verify on a truck with replacement wheels, take-off wheels, or package changes over time. Once the diameter is confirmed, compare the tire’s approved rim-width range and the truck’s actual size on the sidewall, especially on 17-inch setups where two different primary tire sizes are used.
Do all 2020 GMC Trucks Sierra 2500 HD sub-models use the same tire size?
No. The 2020 GMC Trucks Sierra 2500 HD uses different tire sizes across the AT4, Base, Denali, SLE, and SLT trims. Denali uses 275/65R20, while other trims can use combinations of 17-inch, 18-inch, or 20-inch radial sizes depending on how the truck was equipped.
That makes the trim name helpful, but not always sufficient by itself. A Base or SLE truck can span more than one primary size, so checking both the sub-model and the installed wheel diameter is the safest way to narrow the fitment before comparing load capacity, sidewall style, or all-terrain product details.
Choosing the Right Tire
What should I consider when choosing a tire for a 2020 GMC Trucks Sierra 2500 HD?
Start with the exact primary tire size for the truck’s trim and wheel package, then compare the product’s load capacity, rim-width requirement, and intended use. On the 2020 GMC Trucks Sierra 2500 HD, the decision is not only about diameter, since two different 17-inch fitments are also used.
Truck duty matters as much as the size on the sidewall. A Sierra 2500 HD used for towing, payload, or rough-surface work should have a tire that matches the wheel correctly and carries the right load specification, while a truck used more lightly still needs the proper size and wheel pairing to maintain predictable fitment.
What sidewall styles are available for 2020 GMC Trucks Sierra 2500 HD tires?
Sidewall presentation on the available Sierra 2500 HD products includes RWL and RBL, depending on size. The 275/70R18, 245/75R17, and 265/70R17 options use RWL, while the 275/65R20 option uses RBL in the available BFGoodrich All-Terrain T/A KO2 offering.
That choice affects appearance more than fitment, but it can still matter on a truck where the tire is visually prominent. After confirming the correct size and wheel diameter, the sidewall treatment becomes part of the final decision, especially if the goal is a more traditional raised-letter look or a more subdued black sidewall presentation.
What tire series are available for the 2020 GMC Trucks Sierra 2500 HD?
The available products for the 2020 GMC Trucks Sierra 2500 HD are in the BFGoodrich All-Terrain T/A KO2 series. That means the main differences across the current size offerings come from tire size, sidewall style, rim-width range, weight, and load specification rather than from multiple competing series names.
For the buyer, that simplifies comparison somewhat because the series character stays consistent while fitment details change from one size to another. The most important step is still matching the tire to the truck’s actual wheel package, then comparing the product specs within that size, especially where more than one load version is offered.
Restoration & Appearance
Does correct tire fitment matter for a 2020 GMC Trucks Sierra 2500 HD restoration or clean OEM-style appearance?
Yes. Even on a modern heavy-duty truck like the 2020 GMC Trucks Sierra 2500 HD, the right tire size has a strong effect on stance, wheel-to-tire proportion, and overall visual balance. Using the correct 17-, 18-, or 20-inch fitment helps the truck keep the appearance intended by its original wheel package.
Appearance-focused buyers should still begin with the exact trim and wheel setup before deciding on sidewall treatment. An RWL or RBL sidewall can shift the visual character of the truck, but the size itself remains the foundation. A clean, factory-inspired look starts with the right dimensions, then moves to sidewall and tread presentation.
Which sidewall style suits a clean-looking 2020 GMC Trucks Sierra 2500 HD?
That depends on the visual direction of the truck. RWL gives the 2020 GMC Trucks Sierra 2500 HD a more assertive all-terrain look, while RBL creates a quieter appearance. Both styles appear in the available fitments, although the sidewall treatment varies by tire size rather than being offered universally across all four sizes.
The practical order is to choose the correct tire size first, then use sidewall style as the finishing detail. A truck kept close to a stock visual theme may lean toward a simpler black sidewall, while an owner who wants the tire to stand out may prefer raised white letters when that treatment is available in the required size.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2020 GMC Trucks Sierra 2500 HD?
Yes. Wheel changes, suspension lifts or leveling kits, and other aftermarket modifications can affect tire fitment on a 2020 GMC Trucks Sierra 2500 HD even when the tire size looks close to stock. Changes in wheel width or offset can alter clearance at the fenders, suspension components, and steering range.
That is especially important on this truck because several primary sizes already exist across 17-, 18-, and 20-inch wheel packages. On a modified Sierra 2500 HD, confirm the actual wheel dimensions on the truck and check clearance through full steering travel and suspension movement before settling on a replacement tire size.
What should I inspect before driving a 2020 GMC Trucks Sierra 2500 HD on new tires?
Before road use, inspect the wheel diameter and width, confirm the tire matches the truck’s correct size, and check inflation, visible damage, and clearance. The Sierra 2500 HD is a heavy-duty truck, so sidewall condition, seating on the rim, and proper load specification deserve close attention before regular driving or work use.
A short test drive should be followed by another visual inspection for rubbing, uneven seating, or unexpected contact points. It also helps to recheck pressure after the first few miles and verify that the spare, if carried for service use, matches the truck’s wheel and tire setup closely enough for practical roadside use.
How should tires on a 2020 GMC Trucks Sierra 2500 HD be maintained?
Regular maintenance starts with keeping the tires inflated correctly for the truck’s use, watching tread wear, and inspecting for cuts, punctures, bulges, and irregular wear patterns. On a 2020 GMC Trucks Sierra 2500 HD, that routine matters even more when the truck sees towing, hauling, rough roads, or long periods between inspections.
Owners should also keep an eye on age-related condition, especially on trucks that sit for stretches and then return to service. Checking pressure before heavier trips, looking for slow air loss, and inspecting the sidewalls and tread after loading or off-pavement use can catch problems early and help the tire wear more evenly over time.
