The 2018 GMC Trucks Acadia sits in the modern midsize crossover category, balancing family-duty comfort with GMC’s more upscale truck-branded character. Trim level matters on this Acadia because wheel and tire fitment changes across the range, with 245/65R17, 235/65R18, and 235/55R20 radial sizes all appearing depending on configuration. That means the real decision is not simply finding a tire for an Acadia, but matching the correct size to the right sub-model and wheel diameter. Buyers also need to consider how the vehicle is actually equipped today, especially if wheels have been changed, before choosing a road-oriented replacement or a more aggressive alternative.
Which Tire Size Is Right for The 2018 GMC Trucks Acadia
Three tire sizes apply to the 2018 GMC Trucks Acadia, and they vary by sub-model and wheel diameter. The first step is confirming the exact trim and the wheel currently on the vehicle, because this Acadia uses 17-inch, 18-inch, and 20-inch rim diameters. Once that is settled, the next decision becomes choosing the right type of radial tire for the way the vehicle is driven.
A 235/55R20 tire is a metric radial size with a 235-millimeter nominal section width, a 55-series aspect ratio, and fitment for a 20-inch wheel. On the 2018 GMC Trucks Acadia, this size belongs to configurations equipped with the larger wheel package, so wheel confirmation matters before replacement. Its lower-profile format gives this Acadia a different visual stance than the taller 17-inch and 18-inch combinations. This is the size to evaluate when the vehicle already wears 20-inch wheels and the goal is to preserve the proper fitment relationship between tire size and rim diameter.
A 245/65R17 tire is a metric radial size that uses a 245-millimeter nominal section width, a 65-series aspect ratio, and a 17-inch rim. On the 2018 GMC Trucks Acadia, this size appears on certain trims using the smallest wheel diameter in the range. Available product choice here includes a BFGoodrich All-Terrain T/A KO2 with raised white letter styling, giving this size a more rugged character than a typical highway-oriented crossover tire. It is the size to compare when the Acadia has 17-inch wheels and an owner wants to keep that factory-size format while considering a more aggressive tread presentation.
A 235/65R18 tire is a metric radial size with a 235-millimeter nominal section width, a 65-series profile, and fitment for an 18-inch wheel. For the 2018 GMC Trucks Acadia, this size serves as a middle-ground wheel and tire package between the 17-inch and 20-inch setups used elsewhere in the lineup. The taller sidewall profile compared with 235/55R20 is part of what separates this fitment visually and dimensionally, even though both remain modern radial sizes. This is the size to confirm when the vehicle wears 18-inch wheels and the buyer wants to stay with the correct rim-diameter match for that setup.
Tire fitment on the 2018 GMC Trucks Acadia depends on the exact sub-model, and some trims can use more than one wheel-and-tire combination. Checking the trim level first helps narrow the correct size before comparing actual tire choices or confirming whether the vehicle still has its original wheel diameter.
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2018 GMC Trucks Acadia Denali
The 2018 GMC Trucks Acadia Denali uses the 235/55R20 radial size, tying it to the 20-inch wheel setup in this model range. Tire selection here starts with preserving that wheel diameter and then choosing a replacement that matches the vehicle’s current wheel package and intended road use.
The 2018 GMC Trucks Acadia SL uses the 245/65R17 radial size, placing it on the 17-inch wheel fitment. That makes wheel-diameter confirmation straightforward, and the main selection question becomes whether the vehicle needs a standard road replacement or a more truck-oriented tire style in the same size.
The 2018 GMC Trucks Acadia SLE can use 245/65R17, 235/65R18, or 235/55R20 depending on how the vehicle is equipped. This trim requires extra attention because the sub-model name alone does not settle the tire choice without confirming the actual wheel diameter on the vehicle.
The 2018 GMC Trucks Acadia SLT uses either 235/65R18 or 235/55R20, so both 18-inch and 20-inch wheel packages come into play. Tire selection starts with identifying which wheel is on the vehicle now, then matching the replacement tire to that specific setup rather than the trim name alone.
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 2018 GMC Trucks Acadia Tires for Sale
Available product choice for the 2018 GMC Trucks Acadia is centered on 245/65R17, with a BFGoodrich All-Terrain T/A KO2 option in radial construction. It adds an all-terrain tire series, raised white letter sidewall styling, and a 7.0- to 8.0-inch rim-width range to compare against the vehicle’s wheel setup.
These FAQs focus on the exact tire sizes used on the 2018 GMC Trucks Acadia, how fitment changes by sub-model, and what to check when comparing wheel diameter, tire style, and real-world road use.
Tire Size & Fitment
What tire size fits a 2018 GMC Trucks Acadia?
The 2018 GMC Trucks Acadia uses three tire sizes across its range: 245/65R17, 235/65R18, and 235/55R20. All three are radial sizes, and the correct one depends on the trim level and wheel package on the vehicle. Denali uses 235/55R20, SL uses 245/65R17, SLT uses either 235/65R18 or 235/55R20, and SLE can use all three depending on configuration.
That means the safest starting point is the vehicle’s actual wheel diameter, not the model name alone. A quick check of the current sidewall size or the wheel itself helps prevent ordering a 17-inch, 18-inch, or 20-inch tire for the wrong setup. If the Acadia has had aftermarket wheels installed, use the current wheel and tire combination as the fitment reference.
What size rim does a 2018 GMC Trucks Acadia use?
A 2018 GMC Trucks Acadia can use 17-inch, 18-inch, or 20-inch rims depending on sub-model and equipment. The 245/65R17 size fits a 17-inch rim, the 235/65R18 size fits an 18-inch rim, and the 235/55R20 size fits a 20-inch rim. These are not interchangeable rim diameters, so the tire must match the wheel already on the vehicle.
The practical issue is simple: even if two Acadia trims look similar, a 20-inch tire will not mount on an 18-inch wheel, and an 18-inch tire will not mount on a 17-inch wheel. Before comparing brands or tread styles, confirm the wheel diameter stamped on the tire sidewall or by measuring the wheel setup already installed on the vehicle.
Why does the 2018 GMC Trucks Acadia have more than one tire size?
The 2018 GMC Trucks Acadia has more than one tire size because GMC used different wheel-and-tire packages across the trim lineup. SL, Denali, SLT, and SLE do not all share the same setup, and SLE and SLT can appear with more than one fitment. That creates three legitimate tire sizes within the same model year and model name.
For a buyer, that means trim identification is only part of the job. The actual wheel on the vehicle matters just as much, especially on SLE and SLT models that can use more than one diameter. Looking at the existing tire sidewall is often the fastest way to confirm whether the Acadia needs a 17-inch, 18-inch, or 20-inch replacement.
Choosing the Right Tire
What should I consider when choosing a tire for a 2018 GMC Trucks Acadia?
Start with the correct size for the exact Acadia trim and wheel diameter: 245/65R17, 235/65R18, or 235/55R20. From there, compare tire type, sidewall presentation, and how the vehicle is actually used. A daily-driven crossover, a highway-oriented family vehicle, and an Acadia that sees gravel roads or light trail use may point toward different tire styles even within the same size.
Wheel compatibility should stay at the center of the decision. The available 245/65R17 BFGoodrich option, for example, carries a 7.0- to 8.0-inch rim-width range and a more aggressive all-terrain character. Checking the actual wheel width, the vehicle’s current clearance, and whether a more rugged look or road-focused feel is the priority will narrow the best choice.
What sidewall styles are available for 2018 GMC Trucks Acadia tires?
The sidewall style appearing in the available Acadia product selection is RWL, or raised white letter, on the 245/65R17 BFGoodrich All-Terrain T/A KO2. That gives the tire a more traditional truck-style appearance than a plain black sidewall. On an Acadia, that can shift the look noticeably, especially on an SL or similarly equipped model with the 17-inch wheel package.
Sidewall styling does not change the need to match the correct size and wheel diameter. It is best treated as an appearance decision after the fitment basics are settled. Owners who want a more understated look may prefer to keep their search focused on road-oriented tire styles, while those wanting a tougher visual stance may find raised white lettering more appealing.
What brands offer tires for the 2018 GMC Trucks Acadia?
BFGoodrich appears in the available product selection for the 2018 GMC Trucks Acadia, specifically in the 245/65R17 size. That option is the All-Terrain T/A KO2, a radial tire with raised white letter styling and a more aggressive truck-oriented presentation than a typical crossover replacement tire. Brand choice here is tied directly to the exact size and wheel package on the vehicle.
The useful next step is checking whether the Acadia actually uses the size tied to that brand offering. A Denali on 235/55R20, for example, needs a different fitment path than an SL on 245/65R17. Once size is confirmed, compare the tire’s intended character, rim-width compatibility, and how closely it matches the vehicle’s normal road and weather use.
Restoration & Appearance
Does correct tire fitment matter for a 2018 GMC Trucks Acadia restoration?
Correct tire fitment still matters on a 2018 GMC Trucks Acadia even though it is a newer vehicle than a traditional classic. The right size preserves the intended relationship between the wheel diameter, sidewall profile, and overall stance, whether the Acadia uses 245/65R17, 235/65R18, or 235/55R20. Keeping the correct fitment also helps the vehicle retain an appropriately finished appearance for its trim level.
A restoration-oriented or preservation-minded owner should begin by confirming how the vehicle is equipped now and whether the wheels match its original trim presentation. If exact authenticity is important, compare the current setup with factory literature or marque-specific references. Even on a modern collector candidate, the wrong wheel diameter or tire profile can alter the Acadia’s visual balance.
How does tire construction affect the appearance of a restored 2018 GMC Trucks Acadia?
Tire construction is straightforward on the 2018 GMC Trucks Acadia because the primary fitments are radial sizes across the range. That means the visual differences come less from bias-ply-versus-radial decisions and more from the specific size, wheel diameter, sidewall height, and sidewall styling. A 17-inch setup with raised white letters presents differently from a 20-inch road-oriented combination, even though both are radials.
For an appearance-focused build, the main choice is matching the tire’s look to the Acadia’s trim and purpose. Denali owners may want a cleaner, more upscale presentation, while a 17-inch Acadia can lean more utility-oriented with an all-terrain tread and RWL sidewall. The key is keeping the visual style consistent with the vehicle’s wheel package and overall condition.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 GMC Trucks Acadia?
Yes, modifications can affect tire fitment on a 2018 GMC Trucks Acadia. Aftermarket wheels, different wheel widths, suspension changes, or altered ride height can change the clearances that matter to 245/65R17, 235/65R18, or 235/55R20 tires. Even when the sidewall size looks close to stock, a different wheel setup can create new issues at the fender, strut, or steering range.
That is why the current vehicle setup matters more than trim information alone on a modified Acadia. Check wheel diameter first, then confirm width and observe clearance at full steering lock and under normal suspension travel. Any owner moving away from a stock-style wheel should also pay attention to rubbing marks, uneven wear, and whether the tire’s intended rim-width range suits the wheel installed.
What should I inspect before driving a 2018 GMC Trucks Acadia on new tires?
Before driving a 2018 GMC Trucks Acadia on new tires, inspect the wheel size, mounting direction if applicable, inflation pressure, and general clearance around the suspension and fenders. Make sure the new tire size matches the Acadia’s actual wheel diameter and that nothing contacts the tire through the steering range. Lug torque and valve stem condition also deserve attention after installation.
A short road test is useful before longer highway use. Listen for rubbing, feel for vibration, and recheck pressure after the first drive. It also helps to confirm that the spare, if carried, still makes sense alongside the vehicle’s current wheel-and-tire setup. Any unusual pull, shake, or contact should be addressed before the Acadia returns to regular service.
How often should tires on a 2018 GMC Trucks Acadia be inspected?
Tires on a 2018 GMC Trucks Acadia should be inspected regularly, not just when replacement time arrives. A quick visual check for cuts, sidewall damage, uneven tread wear, embedded debris, and air loss is worthwhile at least monthly and before longer trips. Vehicles that alternate between local errands and highway travel can develop wear patterns that are easy to miss without routine checks.
Inspection matters even more if the Acadia sits for extended periods or runs on a more aggressive tire such as an all-terrain 245/65R17. Pressure should be checked cold, and any vibration or pull should prompt a closer look at alignment and tire condition. Consistent inspection helps catch problems early, before they turn into ride issues or roadside trouble.
