The 2018 Audi Trucks SQ5 blends compact luxury SUV practicality with the sharper character expected from Audi’s S models, making tire choice a real part of how the vehicle looks and feels on the road. For this exact SQ5 fitment, the main question is not bias-ply versus radial, but which of its two radial sizes belongs on the wheels currently installed. The SQ5 uses either 255/45R20 or 255/40R21, both modern metric radial sizes with nearly the same overall diameter but different rim diameters. Available choices also vary by brand, tire series, and sidewall treatment, so appearance and driving use both matter. Start by confirming the wheel size, then narrow the selection to the tire style that suits the vehicle.
Which Tire Size Is Right for The 2018 Audi Trucks SQ5
The 2018 Audi Trucks SQ5 uses two primary tire sizes, and the first step is confirming whether the vehicle is on 20-inch or 21-inch wheels. Both sizes are radial and share a very similar overall diameter, so the key difference is wheel diameter and the exact tire profile that matches it. Since both Premium Plus and Prestige models can use either size, wheel identification matters more than trim name when selecting tires.
255/40R21 is a modern metric radial size in which 255 identifies the nominal section width in millimeters, 40 is the aspect ratio, R denotes radial construction, and 21 is the rim diameter in inches. On the 2018 Audi Trucks SQ5, this size suits the 21-inch wheel setup and keeps the low-profile, performance-oriented look associated with larger-diameter sport SUV wheels. Tire selection in this size starts with confirming the actual wheel diameter and then comparing overall tire character, since profile and wheel package matter as much as the trim badge. It is the right size to evaluate only when the SQ5 is already equipped for 21-inch fitment.
255/45R20 is a modern metric radial size that uses a 255-millimeter nominal section width, a 45-series profile, radial construction, and a 20-inch rim diameter. For the 2018 Audi Trucks SQ5, this size belongs to the 20-inch wheel setup and brings the broadest visible product choice here, including BFGoodrich, Nitto, and Pro-Trac options. Blackwall, raised white letter, and redline sidewall treatments are all available in this fitment, along with several tire series. This is the size to focus on when the vehicle wears 20-inch wheels and the goal is to compare both performance-oriented and appearance-driven options within the correct fitment.
Fitment is straightforward across the covered 2018 Audi Trucks SQ5 sub-models because both Premium Plus and Prestige can use the same two radial tire sizes. That makes wheel diameter the deciding factor, so checking whether the vehicle has 20-inch or 21-inch wheels is more important than trim level alone.
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2018 Audi Trucks SQ5 Premium Plus
The 2018 Audi Trucks SQ5 Premium Plus can use either of the two primary radial tire sizes used on this model line. Tire selection starts with confirming whether the vehicle is on 20-inch or 21-inch wheels, then comparing the available tire series and sidewall treatments that match that setup.
The 2018 Audi Trucks SQ5 Prestige shares the same overall tire-fitment pattern as the Premium Plus, with both primary radial sizes applying depending on wheel package. The practical next step is to verify wheel diameter on the vehicle, since trim name alone does not narrow it to one size.
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 Audi Trucks SQ5 Tires for Sale
Available 255/45R20 choices for the 2018 Audi Trucks SQ5 include BFGoodrich, Nitto, and Pro-Trac radial tires across several series. Buyers can compare Blackwall, raised white letter, and redline sidewall treatments, along with rim-width specifications where shown.
These SQ5 tire questions focus on the two correct radial sizes, wheel-diameter differences, available sidewall and brand choices, and the fitment checks that matter before road use.
Tire Size & Fitment
What tire size fits a 2018 Audi Trucks SQ5?
The 2018 Audi Trucks SQ5 uses two primary tire sizes: 255/45R20 and 255/40R21. Both are radial sizes, and both Premium Plus and Prestige sub-models can use either one depending on the wheel setup installed on the vehicle.
That means the first thing to confirm is not just the trim level, but the actual wheel diameter on the SQ5. A 20-inch wheel requires the 255/45R20 size, while a 21-inch wheel requires 255/40R21. Even though the two sizes are very close in overall diameter, they are not the same fitment because they mount to different rim diameters.
What size rim does a 2018 Audi Trucks SQ5 use?
A 2018 Audi Trucks SQ5 can use either a 20-inch or 21-inch rim, depending on which tire size is on the vehicle. The 255/45R20 size matches a 20-inch rim, and the 255/40R21 size matches a 21-inch rim.
Rim diameter is the critical measurement to verify before comparing tires, because the correct tire must match the wheel exactly. Looking only at the tire’s width can be misleading since both SQ5 sizes share the same 255-millimeter width. Check the size molded on the existing tire sidewall and confirm the wheel setup before choosing between available replacement options.
Do all 2018 Audi Trucks SQ5 sub-models use the same tire size?
The 2018 Audi Trucks SQ5 Premium Plus and Prestige follow the same fitment pattern, but that does not mean every vehicle wears one single tire size. Both sub-models can use either 255/45R20 or 255/40R21, depending on the wheel package on the vehicle.
In practical terms, the sub-model name does not narrow the choice as much as the wheel diameter does. A buyer should verify what is actually on the vehicle now, especially if wheels may have been changed. Once the 20-inch or 21-inch setup is confirmed, the tire decision becomes much simpler and shifts to series, sidewall style, and intended driving use.
Choosing the Right Tire
What should I consider when choosing a 255/45R20 tire for a 2018 Audi Trucks SQ5?
Start with the basics: the tire must be the correct 255/45R20 size for a 20-inch wheel, and it should suit how the SQ5 is actually used. In this fitment, available choices differ by brand, tire series, sidewall style, rim-width specification, weight, and in one case a stated maximum load capacity of 1819 at 51 psi.
After confirming size, compare the tire’s overall presentation and intended character. Blackwall choices keep a more understated look, while raised white letter and redline versions create a stronger visual statement. It also helps to confirm the wheel width before choosing among products, since some options include a stated 8.0 to 9.5 inch rim-width range and the vehicle may not still be on its original wheel setup.
What sidewall styles are available for 2018 Audi Trucks SQ5 tires?
For the 2018 Audi Trucks SQ5 in 255/45R20, available sidewall styles include Blackwall, RWL, and Redline. Blackwall appears on BFGoodrich and Nitto options, while Pro-Trac Street Pro III is available with either raised white letters or a redline treatment.
The sidewall choice affects appearance more than basic fitment, but it can make a noticeable difference on an SUV with sporty styling like the SQ5. Blackwall keeps the most contemporary look, while RWL and redline add a more distinct enthusiast presentation. Once the wheel diameter and tire size are confirmed, sidewall style becomes one of the easiest ways to tailor the finished look without changing the underlying fitment.
What brands offer tires for the 2018 Audi Trucks SQ5?
Available 255/45R20 tires for the 2018 Audi Trucks SQ5 come from BFGoodrich, Nitto, and Pro-Trac. The fitment includes several tire series, including g-Force Comp 2 AS, g-Force Sport Comp 2, Nitto NT555 G2, and Pro-Trac Street Pro III.
Brand is only one part of the decision, so it helps to compare each option in the context of the full specification and visual style. Some choices emphasize a conventional Blackwall appearance, while others offer raised white letter or redline sidewalls. Buyers should also compare any stated rim-width and load details where shown, especially if the SQ5 has aftermarket wheels or is used for more than occasional driving.
Restoration & Appearance
Which tire should I choose for a period-style 2018 Audi Trucks SQ5?
A period-style choice for a 2018 Audi Trucks SQ5 starts with using the correct modern radial size for the wheel package already on the vehicle, either 255/45R20 or 255/40R21. Since this is a late-model performance SUV rather than a vintage restoration project, the visual decision is usually about wheel diameter and sidewall presentation rather than recreating an older bias-ply look.
For a cleaner contemporary appearance, Blackwall options keep the presentation closest to what many owners expect on a modern Audi performance utility vehicle. A redline or raised white letter tire creates a more customized look and should be chosen intentionally. If originality matters closely, compare the vehicle’s current wheel-and-tire presentation with marque-specific references before making an appearance-driven change.
How does tire construction affect the appearance of a restored 2018 Audi Trucks SQ5?
On the 2018 Audi Trucks SQ5, construction does not create a bias-ply versus radial decision because the primary fitments are radial. Appearance is shaped more by the chosen wheel diameter, tire profile, and sidewall treatment than by switching between different construction eras.
That makes the visual choice fairly focused. A 21-inch setup with 255/40R21 delivers a lower-profile look, while a 20-inch setup with 255/45R20 carries a slightly fuller sidewall on the correct wheel. Within the available 20-inch products, Blackwall, raised white letter, and redline treatments further change the character. Keeping size and wheel diameter correct is the foundation for any restoration-oriented or presentation-focused result.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 Audi Trucks SQ5?
Yes. Modifications can affect tire fitment on a 2018 Audi Trucks SQ5 even when the tire size looks close to stock. Aftermarket wheels, changes in wheel width, offset differences, suspension lowering, or brake upgrades can all influence whether 255/45R20 or 255/40R21 works properly on the vehicle.
The best approach is to confirm the actual wheel dimensions and inspect for clearance at full steering lock and through suspension travel before settling on a replacement tire. A modified SQ5 may need more careful checking than one on an unaltered factory-style setup. Sidewall proximity to fenders, inner liners, and suspension components matters just as much as matching the basic tire size.
What should I inspect before driving a 2018 Audi Trucks SQ5 on new tires?
Before driving a 2018 Audi Trucks SQ5 on new tires, inspect the wheels for damage, confirm the tire size matches the rim diameter, and check that all four tires are inflated evenly and seated properly. It is also smart to look over the valve stems, lug torque, and the basic condition of the suspension and steering components.
A short road test should include listening for rubbing, vibration, or pull that could point to fitment or installation issues. Since the SQ5 can use either 20-inch or 21-inch wheel setups, tire-to-wheel matching is especially important. Recheck pressure after the first drives, and keep an eye on tread wear patterns that may suggest alignment or wheel-position issues rather than a problem with the tire itself.
How often should tires on a 2018 Audi Trucks SQ5 be inspected?
Tires on a 2018 Audi Trucks SQ5 should be inspected regularly, not just when tread looks low. Pressure, tread wear, cuts, punctures, bulges, and sidewall damage all deserve routine attention, especially on a performance-oriented vehicle using lower-profile radial tires.
A quick visual check before longer drives is a good habit, and a more careful inspection should follow any pothole strike or curb contact. Uneven wear can reveal alignment issues, while repeated air loss may point to wheel or valve problems. If the SQ5 is driven infrequently, inspection still matters because age, storage conditions, and underinflation can affect tire condition even when mileage remains low.
