The 2020 Mercedes-Benz Trucks GLS450 is a full-size luxury SUV built around long-distance comfort, modern road manners, and the substantial stance expected from a premium utility vehicle. Tire choice on this model is less about vintage-style construction and more about matching the exact wheel and position-specific fitment the vehicle uses. Depending on configuration, the GLS450 runs radial sizes 275/55R19, 275/50R20, or a staggered 21-inch setup with 275/45R21 in front and 315/40R21 in the rear. That makes wheel diameter and, on 21-inch applications, front-to-rear placement the key starting points before comparing replacement tires for everyday driving, appearance, or overall setup consistency.
Which Tire Size Is Right for The 2020 Mercedes-Benz Trucks GLS450
The 2020 Mercedes-Benz Trucks GLS450 uses four primary tire sizes, and the correct one depends on the wheel diameter and the exact sub-model or axle position. Start by confirming whether the SUV has 19-inch wheels, 20-inch wheels, or the staggered 21-inch front-and-rear setup, because choosing by model name alone is not enough on this application.
The 275/50R20 size is a modern metric radial format: 275 is the nominal section width in millimeters, 50 is the aspect ratio, R identifies radial construction, and 20 is the wheel diameter in inches. On the 2020 Mercedes-Benz Trucks GLS450, this size belongs to a 20-inch wheel application rather than the 19-inch or staggered 21-inch setups. Its dimensions place it in the same general overall height range as the other GLS450 fitments, but the wheel requirement remains specific. This is the right size to evaluate only after confirming the vehicle is equipped with the matching 20-inch wheel package.
The 275/55R19 size uses the same modern metric radial format, with a 275-millimeter nominal width, a 55-series profile, radial construction, and a 19-inch rim diameter. For the 2020 Mercedes-Benz Trucks GLS450, this size serves a different wheel setup from the 20-inch and 21-inch applications, so it should be treated as its own fitment path. The slightly taller sidewall profile is part of what separates it from the other sizes used on this model. Confirming the actual wheel diameter on the vehicle is the practical first step before comparing replacement tire choices in this size.
The 275/45R21 size is a modern metric radial with a 275-millimeter nominal section width, a 45-series aspect ratio, radial construction, and a 21-inch rim diameter. On the 2020 Mercedes-Benz Trucks GLS450, this is the front tire size for the staggered 21-inch arrangement, so it is not intended to stand in for every GLS450 wheel package. Its role is tied to position as much as diameter, which matters when replacing tires in pairs or as a full set. Front-wheel clearance and maintaining the proper front-to-rear sizing relationship should both be checked before making a selection.
The 315/40R21 size is also a modern metric radial, but it is substantially wider than the 275-millimeter front sizes used elsewhere on the 2020 Mercedes-Benz Trucks GLS450. Here, 315 is the nominal section width in millimeters, 40 is the aspect ratio, R indicates radial construction, and 21 is the wheel diameter in inches. This size is used on the rear of the staggered 21-inch setup, pairing with 275/45R21 at the front rather than functioning as a universal GLS450 fitment. Rear position, wheel width, and clearance all matter when replacing this size on a staggered vehicle.
Fitment on the 2020 Mercedes-Benz Trucks GLS450 varies by sub-model and wheel setup rather than following one uniform tire size across every application. Checking the exact configuration matters here, especially because the 21-inch arrangement uses different front and rear sizes.
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2020 Mercedes-Benz Trucks GLS450 4Matic
The 2020 Mercedes-Benz Trucks GLS450 4Matic uses either 275/50R20 or 275/55R19, so the deciding factor is the actual wheel diameter on the vehicle. That makes wheel confirmation more important than brand shopping at the start, since the correct replacement path changes between the 19-inch and 20-inch setups.
The 2020 Mercedes-Benz Trucks GLS450 4Matic Front uses 275/45R21 as part of the 21-inch staggered setup. Tire selection here should preserve the correct front position fitment and be considered alongside the matching rear size rather than treated as a standalone all-around GLS450 size.
The 2020 Mercedes-Benz Trucks GLS450 4Matic Rear uses 315/40R21 on the rear axle of the staggered 21-inch package. That means replacement planning should account for the wider rear fitment, the matching front size, and the wheel setup already on the vehicle before any size change is considered.
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
Owners of a 2020 Mercedes-Benz Trucks GLS450 usually need clarity on exact tire size, wheel diameter, staggered front-to-rear fitment, and what to inspect before replacing tires. These FAQs focus on matching the right size to the right setup and avoiding costly fitment mistakes.
Tire Size & Fitment
What tire size fits a 2020 Mercedes-Benz Trucks GLS450?
The 2020 Mercedes-Benz Trucks GLS450 uses four primary radial tire sizes: 275/55R19, 275/50R20, 275/45R21, and 315/40R21. The correct fitment depends on the exact wheel package and, on 21-inch applications, the tire's position on the vehicle because the front and rear do not use the same size.
The practical first step is checking the wheel diameter already on the SUV and confirming whether it has a square setup or the staggered 21-inch arrangement. A GLS450 with 19-inch or 20-inch wheels follows a different replacement path than one with 21-inch front and rear sizes, so the tire sidewall and wheel should both be verified before ordering.
What size rim does a 2020 Mercedes-Benz Trucks GLS450 use?
The 2020 Mercedes-Benz Trucks GLS450 uses 19-inch, 20-inch, and 21-inch rim diameters depending on configuration. The 275/55R19 fits a 19-inch rim, the 275/50R20 fits a 20-inch rim, and the staggered setup uses 21-inch rims with 275/45R21 in front and 315/40R21 in the rear.
Rim diameter should be confirmed before looking at tread pattern or brand because the tire sizes are tied directly to those wheel packages. On a used GLS450, it is also smart to confirm that the wheels are still the original diameter for that setup, since aftermarket wheel changes can make the vehicle's model designation less useful than the actual wheel and tire markings.
Why does the 2020 Mercedes-Benz Trucks GLS450 have more than one tire size?
More than one tire size appears on the 2020 Mercedes-Benz Trucks GLS450 because the model was offered with different wheel packages, including 19-inch, 20-inch, and staggered 21-inch fitments. The 21-inch setup is especially important because it uses one size in front, 275/45R21, and a wider size in the rear, 315/40R21.
That means tire selection cannot be based on model name alone. The right approach is to identify the exact wheel diameter and then confirm whether the SUV uses the same size at all four corners or a staggered arrangement, since mixing square and staggered fitment assumptions can create avoidable clearance, balance, and replacement-planning issues.
Choosing the Right Tire
What should I consider when choosing a tire for a 2020 Mercedes-Benz Trucks GLS450?
Start with the exact size already assigned to the vehicle's wheel setup: 275/55R19, 275/50R20, 275/45R21 front, or 315/40R21 rear. On the 2020 Mercedes-Benz Trucks GLS450, the biggest selection mistake is choosing by model alone instead of confirming wheel diameter and whether the vehicle uses a square or staggered arrangement.
After size is confirmed, focus on keeping the fitment consistent with the wheel package and the vehicle's intended use. Daily road use, even tread wear, and balanced handling all benefit from using the proper front and rear sizes, while any wheel change should be checked carefully so section width, clearance, and the overall setup remain appropriate.
How do I choose between the available tire sizes for a 2020 Mercedes-Benz Trucks GLS450?
The available sizes are not alternatives to choose freely across the model; they correspond to different wheel and axle configurations on the 2020 Mercedes-Benz Trucks GLS450. A 19-inch GLS450 needs 275/55R19, a 20-inch version needs 275/50R20, and a 21-inch staggered vehicle uses 275/45R21 in front with 315/40R21 in the rear.
That makes the decision process straightforward once the hardware on the vehicle is confirmed. Check the sidewall markings on the existing tires, verify the wheel diameter, and make sure the rear size matches the front arrangement on 21-inch setups, especially if the SUV was purchased used or may have been altered from its original wheel package.
What rim-fitment details should I compare when choosing 2020 Mercedes-Benz Trucks GLS450 tires?
Rim diameter is the first fitment detail to compare on a 2020 Mercedes-Benz Trucks GLS450 because its primary sizes are tied to 19-inch, 20-inch, or 21-inch wheels. On 21-inch applications, axle position matters too, since the front uses 275/45R21 while the rear uses the wider 315/40R21.
Beyond diameter, the buyer should make sure the wheel setup on the vehicle still matches the intended tire size. A used GLS450 may have aftermarket wheels or replacement rims, and those changes can affect width compatibility and clearance, so checking the wheel itself is just as important as reading the size molded into the existing tire.
Restoration & Appearance
Does correct tire fitment matter for a 2020 Mercedes-Benz Trucks GLS450 restoration or cosmetic refresh?
Yes. Even on a modern luxury SUV like the 2020 Mercedes-Benz Trucks GLS450, correct tire fitment matters because the vehicle's stance and overall presentation depend on using the right size for the wheel package. The difference between 19-inch, 20-inch, and staggered 21-inch fitments is visible as well as functional.
A cosmetic refresh should still begin with exact size verification rather than appearance alone. Matching the proper front and rear sizes on 21-inch vehicles helps preserve the intended look, while replacing a tire with the wrong wheel-diameter fitment can disrupt proportions and create avoidable fitment issues even if the tread style initially looks appropriate.
How does tire fitment affect the appearance of a 2020 Mercedes-Benz Trucks GLS450?
Tire fitment has a noticeable effect on the appearance of a 2020 Mercedes-Benz Trucks GLS450 because the SUV was offered with multiple wheel diameters and, in some cases, a staggered 21-inch layout. The 275/45R21 front and 315/40R21 rear combination creates a different visual balance than the 19-inch or 20-inch square setups.
Appearance should still follow correct sizing rather than the other way around. A buyer trying to maintain the vehicle's intended proportions should verify the existing wheel package first, then replace tires within that fitment path so the sidewall height, wheel-to-tire relationship, and front-to-rear stance remain consistent with the setup already on the SUV.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2020 Mercedes-Benz Trucks GLS450?
Yes. Modifications can change tire fitment on a 2020 Mercedes-Benz Trucks GLS450, especially if the SUV has aftermarket wheels, altered suspension height, or nonstandard front-to-rear sizing. That matters most on 21-inch vehicles, where the factory-style arrangement already uses different front and rear tire widths.
A modified GLS450 should be checked at the wheel, not just by model designation. Confirm wheel diameter, verify the tire sizes currently mounted, and inspect for clearance around the fenders, suspension, and steering components before changing tires, since even a correct nominal size can become more complicated when the wheel or ride-height setup has changed.
What should I inspect before driving a 2020 Mercedes-Benz Trucks GLS450 on new tires?
Before driving a 2020 Mercedes-Benz Trucks GLS450 on new tires, check that each tire matches the correct size for the wheel diameter and axle position. Also inspect inflation pressure, bead seating, valve condition, and the visible clearance around suspension and body components, particularly if the SUV uses the staggered 21-inch front-and-rear setup.
A short inspection drive is worthwhile after installation. Pay attention to rubbing, vibration, steering feel, and whether the front and rear sizes were mounted in their proper positions, since a staggered arrangement leaves less room for simple installation mistakes than a square setup where all four tires use the same dimensions.
What should I check before a longer drive in a 2020 Mercedes-Benz Trucks GLS450?
Before a longer drive in a 2020 Mercedes-Benz Trucks GLS450, confirm that the tire sizes match the wheel package on the vehicle and that front and rear positions are correct on any 21-inch staggered setup. Tread condition, air pressure, sidewall condition, and any signs of impact damage should also be checked before highway use.
Longer trips are a good time to catch issues that short local driving may hide. A used GLS450 with replacement wheels or mixed tire history deserves extra attention, so look for uneven wear, confirm there is no contact at full steering lock, and recheck pressures after the tires have settled into regular use.
