The 2018 Mercedes-Benz Trucks GLS450 sits in the modern full-size luxury SUV class, blending three-row comfort with the substantial stance and road presence buyers expect from a premium utility vehicle. For owners shopping tires at this level, appearance matters, but so do wheel size, load capability, and preserving the vehicle’s intended ride character. The 2018 Mercedes-Benz Trucks GLS450 uses radial tires in two primary sizes, 275/55R19 and 275/50R20, depending on the wheel setup on the vehicle. That makes wheel confirmation the first step before comparing replacement options. Once the correct size is identified, the focus shifts to choosing the right fit for everyday driving, long-distance use, and the vehicle’s existing wheel package.
Which Tire Size Is Right for The 2018 Mercedes-Benz Trucks GLS450
The 2018 Mercedes-Benz Trucks GLS450 uses two primary tire sizes, and the difference comes down to wheel diameter rather than a change in basic tire construction. Both sizes are radial, but one fits a 19-inch wheel and the other fits a 20-inch wheel, so confirming the actual wheel package on the vehicle is the first and most important step before selecting a tire.
The size 275/50R20 identifies a metric radial tire with a 275 millimeter nominal section width, a 50-series aspect ratio, and fitment for a 20-inch rim. On the 2018 Mercedes-Benz Trucks GLS450, this size supports a lower-profile look than the 19-inch option while remaining within the vehicle’s primary radial fitment range. Its dimensions keep it close in overall height to the alternate size, but the wheel diameter is different, so wheel confirmation is essential. This size should be chosen only when the GLS450 is equipped with the matching 20-inch wheel setup.
The size 275/55R19 is a metric radial format, with 275 millimeters of nominal section width, a 55-series profile, and fitment for a 19-inch rim. For the 2018 Mercedes-Benz Trucks GLS450, it is one of the two primary tire sizes and serves vehicles equipped with the 19-inch wheel package. Its overall diameter stays very close to the 20-inch alternative, but the tire is built around a different wheel diameter and cannot be selected by size similarity alone. This makes it a wheel-specific fitment choice rather than a styling variation.
Sub-model fitment is straightforward here because the covered GLS450 4Matic can use either of the two primary radial tire sizes. Even so, the correct choice still depends on confirming whether the vehicle is wearing 19-inch or 20-inch wheels.
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2018 Mercedes-Benz Trucks GLS450 4Matic
The 2018 Mercedes-Benz Trucks GLS450 4Matic uses radial tires and can be equipped with either of the two primary sizes tied to this model. Tire selection starts with measuring or verifying the wheel diameter, then matching the replacement tire to the existing 19-inch or 20-inch setup.
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.
Frequently Asked Questions
Common questions for the 2018 Mercedes-Benz Trucks GLS450 usually center on the two tire sizes, the 19-inch versus 20-inch wheel setup, and what owners should verify before replacing tires on a modified or low-mileage vehicle.
Tire Size & Fitment
What tire size fits a 2018 Mercedes-Benz Trucks GLS450?
The 2018 Mercedes-Benz Trucks GLS450 uses two primary tire sizes: 275/55R19 and 275/50R20. Both are radial tire sizes, and both apply to the GLS450 4Matic depending on which wheel package is installed on the vehicle.
Choosing between them is not a matter of preference alone, because each size is built for a different rim diameter. A quick check of the current wheel size, tire sidewall, or wheel markings will confirm whether the vehicle needs the 19-inch or 20-inch fitment before any replacement tire comparison begins.
What size rim does a 2018 Mercedes-Benz Trucks GLS450 use?
A 2018 Mercedes-Benz Trucks GLS450 uses either a 19-inch or 20-inch rim, depending on the tire size fitted to the vehicle. The 275/55R19 tire fits a 19-inch rim, while the 275/50R20 tire fits a 20-inch rim.
That rim diameter difference is the key fitment detail to verify before ordering tires. Even though the two tire sizes are close in overall diameter, the wheel itself determines which size belongs on the vehicle, so owners should confirm the existing wheel package rather than relying on appearance alone.
Why does the 2018 Mercedes-Benz Trucks GLS450 have more than one tire size?
The 2018 Mercedes-Benz Trucks GLS450 has more than one tire size because it was equipped with different wheel diameters. One fitment uses 275/55R19 and the other uses 275/50R20, with both serving as primary radial sizes for the GLS450 4Matic.
This kind of variation is common when a vehicle is offered with alternate wheel packages. The practical takeaway is simple: identify the actual wheel diameter on the SUV first, then shop within the matching tire size so the replacement remains compatible with the rim and the vehicle’s intended setup.
Choosing the Right Tire
What should I consider when choosing a tire for a 2018 Mercedes-Benz Trucks GLS450?
Start with the correct primary size for the wheel already on the vehicle, either 275/55R19 or 275/50R20. Since the GLS450 uses two wheel diameters, getting that first step right matters more than comparing tread patterns or brand preferences.
After size confirmation, look at how the vehicle is used and whether the current wheel and suspension setup remain stock. Ride quality, seasonal driving needs, load demands, and any wheel changes all affect tire choice, so the right tire is the one that matches both the existing fitment and the vehicle’s real-world use.
How do I choose between the available 275/55R19 and 275/50R20 tires for a 2018 Mercedes-Benz Trucks GLS450?
The choice between 275/55R19 and 275/50R20 is determined by the wheel diameter on the 2018 Mercedes-Benz Trucks GLS450. Those sizes are not interchangeable choices for the same rim, even though their overall dimensions are relatively close.
Once the wheel size is confirmed, compare tires within that one size instead of crossing between the two fitments. Owners should pay attention to intended road use, replacement quality, and whether the SUV still has its original wheel package or has been changed with aftermarket wheels since new.
Should I match the existing tire size on my 2018 Mercedes-Benz Trucks GLS450 or recheck the wheels first?
Matching the existing tire size is a good starting point, but the wheel should still be rechecked first on a 2018 Mercedes-Benz Trucks GLS450. This model uses either 275/55R19 or 275/50R20, and each size belongs to a different rim diameter.
That extra verification matters most on used vehicles, where wheel swaps are common and an old tire may not reflect the setup you expect. Confirm the wheel diameter directly, then compare the tire size on the vehicle so the next set matches both the rim and the GLS450’s present configuration.
Restoration & Appearance
Does correct tire fitment matter for a 2018 Mercedes-Benz Trucks GLS450 restoration or preservation project?
Correct tire fitment still matters on a 2018 Mercedes-Benz Trucks GLS450, even though it is a newer collector-era vehicle rather than a traditional restoration car. Using the proper 275/55R19 or 275/50R20 size keeps the wheel-to-tire relationship in line with the vehicle’s intended setup.
For an owner preserving original character, the most important detail is keeping the tire matched to the factory-style wheel diameter already on the SUV. If the vehicle has changed hands or has had wheel upgrades, verify the current setup carefully before replacing tires so the stance and fitment remain coherent.
How does tire size affect the appearance of a 2018 Mercedes-Benz Trucks GLS450?
Tire size has a visible effect on the appearance of a 2018 Mercedes-Benz Trucks GLS450 because the vehicle uses either a 19-inch or 20-inch wheel package. The 275/50R20 setup presents a shorter sidewall, while the 275/55R19 setup uses a taller sidewall on the smaller rim.
That difference changes the visual balance between wheel and tire even when overall diameter remains close. Owners trying to preserve a stock-style look should replace tires in the same size already matched to the vehicle’s wheels, rather than treating the two fitments as purely cosmetic alternatives.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 Mercedes-Benz Trucks GLS450?
Yes, modifications can affect tire fitment on a 2018 Mercedes-Benz Trucks GLS450. Wheel changes, suspension alterations, spacers, or ride-height adjustments can all change how a 275/55R19 or 275/50R20 tire sits in the wheel opening and how much clearance remains during steering and suspension travel.
A GLS450 that no longer has its original wheel package should be checked carefully before replacement tires are chosen. Confirm wheel diameter first, then review wheel width, offset, and clearance around the fenders and suspension so the next tire matches the vehicle’s actual modified setup rather than an assumed stock one.
What should I inspect before driving a 2018 Mercedes-Benz Trucks GLS450 on new tires?
Before driving a 2018 Mercedes-Benz Trucks GLS450 on new tires, inspect the wheel size, confirm the new tires match the correct 19-inch or 20-inch fitment, and check inflation, bead seating, and valve condition. It also helps to make sure tread and sidewalls are free from shipping or installation damage.
A short visual check around the wheel wells is worthwhile before regular road use. Look for clearance concerns at full steering lock, verify there is no rubbing, and keep an eye on pressure stability during the first several drives so any fitment or mounting issue is caught early.
How often should tires on a 2018 Mercedes-Benz Trucks GLS450 be inspected?
Tires on a 2018 Mercedes-Benz Trucks GLS450 should be inspected regularly, especially if the vehicle sees family travel, highway use, or long periods of inactivity between drives. Pressure, tread wear, sidewall condition, and any signs of cuts, bulges, or irregular wear should be checked as part of normal ownership.
Low-mileage SUVs can still develop age-related tire concerns even when tread depth looks good. A routine inspection before longer trips is a sensible habit, and any uneven wear pattern should prompt a closer look at alignment, suspension condition, or wheel changes that may be affecting the tire’s contact with the road.
