The 2021 Audi S4 sits in the modern sport-sedan sweet spot, combining understated Audi styling with the sharper road manners buyers expect from the S-badged version of the A4. That balance makes tire choice especially important, because the car’s character depends heavily on maintaining the right overall size, profile, and wheel diameter. This S4 uses radial tires in two primary sizes, 245/40R18 and 255/35R19, tied to 18-inch and 19-inch wheel setups. Available choices range from blackwall performance radials to redline and raised white letter options in 18-inch fitment. The key is matching the tire to the wheel package already on the car and the kind of appearance and driving use you want.
Which Tire Size Is Right for The 2021 Audi S4
The 2021 Audi S4 uses two primary tire sizes, and the first step is confirming whether the car is on an 18-inch or 19-inch wheel package. All three covered sub-models can use either size, so the real fitment decision centers on wheel diameter first, then on sidewall style, tire series, and intended use within the correct radial size.
A 245/40R18 tire uses a 245-millimeter section width, a 40-series profile, radial construction, and an 18-inch rim diameter. On the 2021 Audi S4, this size is part of the modern low-profile radial fitment that supports the car’s sport-sedan balance without drifting into older sizing conventions. Available choices include blackwall designs from M&H Racemaster, BFGoodrich, and Nitto, along with Pro-Trac Street Pro III versions in redline and raised white letter form. This size is the one to evaluate if the car already has 18-inch wheels and you want to compare appearance and performance-oriented tire series within that setup.
A 255/35R19 tire steps up to a 255-millimeter section width, uses a 35-series profile, keeps radial construction, and fits a 19-inch rim. For the 2021 Audi S4, this size belongs to the larger wheel package, so wheel diameter confirmation matters before looking at anything else. The available 19-inch choices center on BFGoodrich g-Force series options in blackwall form, including all-season and sport-focused lines. This is the size to consider when the car is already equipped with 19-inch wheels and the goal is staying with the proper low-profile metric fitment for that wheel package.
Tire fitment is straightforward across the covered 2021 Audi S4 sub-models because Premium, Premium Plus, and Prestige all use the same two primary radial sizes. The important check is not trim level but whether the car is currently on 18-inch or 19-inch wheels.
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2021 Audi S4 Premium
The 2021 Audi S4 Premium can use either of the core radial fitments, so tire selection starts with confirming the wheel diameter on the car. Once that is settled, the choice shifts to product style, tire series, and whether a blackwall or more appearance-driven 18-inch option better suits the build.
The 2021 Audi S4 Premium Plus shares the same basic tire-fitment path as the other covered trims, with 18-inch and 19-inch radial setups both in play. That makes wheel verification the first step, followed by a comparison of the available performance-oriented products in the matching size.
The 2021 Audi S4 Prestige follows the same fitment pattern, so trim level alone does not narrow the tire size down to one option. Tire choice depends on the wheel package already installed, then on whether the goal is a standard blackwall performance look or a more distinctive sidewall treatment in 18-inch fitment.
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 2021 Audi S4 Tires for Sale
Available 2021 Audi S4 tire choices center on 245/40R18 and 255/35R19 radial fitments, with options from BFGoodrich, Nitto, M&H Racemaster, and Pro-Trac. Buyers can compare blackwall performance tires across several series, while 245/40R18 also adds redline and raised white letter alternatives.
These 2021 Audi S4 tire FAQs focus on the two correct radial sizes, 18-inch versus 19-inch wheel fitment, sidewall and series choices, and the practical checks to make before regular road use or after modifications.
Tire Size & Fitment
What tire size fits a 2021 Audi S4?
The 2021 Audi S4 uses two primary tire sizes: 245/40R18 and 255/35R19. Both are modern metric radial sizes, and both appear across Premium, Premium Plus, and Prestige trim levels rather than being limited to just one covered sub-model.
The deciding factor is the wheel package already on the car. A 245/40R18 tire belongs on an 18-inch rim, while a 255/35R19 tire belongs on a 19-inch rim, so confirming wheel diameter should come before comparing brands, sidewall styles, or tire series.
What size rim does a 2021 Audi S4 use?
A 2021 Audi S4 uses either an 18-inch or 19-inch rim, depending on which tire size is on the car. The 245/40R18 fitment uses an 18-inch rim, and the 255/35R19 fitment uses a 19-inch rim.
That means rim diameter cannot be guessed from trim level alone, since all covered sub-models can use both sizes. Checking the existing wheel diameter is the quickest way to avoid ordering the wrong tire, and it also helps narrow the available product choices to the correct profile and sidewall options.
Do all 2021 Audi S4 sub-models use the same tire size?
Premium, Premium Plus, and Prestige all share the same two primary tire sizes: 245/40R18 and 255/35R19. In other words, the fitment pattern is consistent across the covered 2021 Audi S4 sub-models even though there are two different wheel-and-tire combinations.
That makes the trim badge less important than the actual wheels on the car. A buyer should confirm whether the S4 is currently equipped with 18-inch or 19-inch rims, especially if the car has changed hands, has seasonal wheel sets, or has been updated from its original wheel package.
Choosing the Right Tire
What should I consider when choosing a tire for a 2021 Audi S4?
Start with the correct primary size for the wheel package on the car: 245/40R18 for 18-inch rims or 255/35R19 for 19-inch rims. From there, compare radial construction details such as tire series, sidewall treatment, rim-width compatibility, load capacity figures where shown, and whether the tire is aimed at street performance or specialty use.
The right choice depends on how the S4 is driven and how you want it to look. A blackwall performance radial keeps the presentation modern and straightforward, while certain 18-inch options add redline or raised white letter styling for a more distinctive visual character.
What sidewall styles are available for 2021 Audi S4 tires?
Sidewall choices for the 2021 Audi S4 include blackwall, redline, and RWL, or raised white letter. Most of the available product range is blackwall, while the redline and raised white letter treatments appear in the 245/40R18 fitment.
That means sidewall style is part of the selection process once the wheel diameter is confirmed. Buyers staying with 19-inch fitment will be looking at blackwall-only options here, while 18-inch fitment opens the door to a more custom or throwback appearance without changing the underlying metric radial sizing.
What brands offer tires for the 2021 Audi S4?
Tires for the 2021 Audi S4 are available here from BFGoodrich, Nitto, M&H Racemaster, and Pro-Trac. Brand coverage varies by size, with the 245/40R18 fitment offering the broadest mix and the 255/35R19 fitment centered on BFGoodrich g-Force series products.
Brand is only one part of the decision, though. It helps to compare each tire’s series, sidewall style, and intended character within the correct size, especially if the goal is balancing a performance-oriented road setup with a certain visual style on the car.
Restoration & Appearance
Which tire should I choose for a period-style 2021 Audi S4?
A period-style approach on a 2021 Audi S4 still starts with the correct modern radial size for the wheel package already on the car. Within the available choices, 245/40R18 offers the widest appearance range, including blackwall, redline, and raised white letter options that can shift the car’s presentation more than the 19-inch blackwall selections.
Since this is a recent performance sedan, the decision is usually less about strict restoration and more about visual direction. Matching the tire to the wheel diameter and the car’s overall look will matter more than chasing a one-style-fits-all answer, especially if the S4 has aftermarket wheels or cosmetic modifications.
How does tire construction affect the appearance of a restored 2021 Audi S4?
On a 2021 Audi S4, construction does not create a bias-ply-versus-radial appearance question because the primary fitments are radial. The visual difference comes more from sidewall treatment, profile, and wheel diameter, with 18-inch and 19-inch setups giving the car a slightly different stance and proportion.
Appearance-minded buyers should focus on choosing the correct metric size first, then deciding whether a blackwall, redline, or raised white letter look best suits the project. That approach keeps the car within its intended sizing while still allowing some flexibility in how traditional or custom the finished presentation feels.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2021 Audi S4?
Yes, modifications can affect tire fitment on a 2021 Audi S4 even when the tire size itself is correct. Aftermarket wheels, changes in wheel width, altered offset, lowering springs, suspension work, or body changes can all influence clearance around the fenders, suspension components, and steering range.
That matters most when moving between the car’s 18-inch and 19-inch setups or when buying tires for a modified car with unknown wheel specifications. Checking actual wheel diameter and width, then confirming clearance at full lock and through suspension travel, helps prevent avoidable fitment surprises.
What should I inspect before driving a 2021 Audi S4 on new tires?
Before driving a 2021 Audi S4 on new tires, inspect the wheels for damage, confirm the correct tire size for the rim diameter, and make sure the tires are seated and inflated properly. It also helps to check for any rubbing points near the fenders, suspension, and steering components once the car is back on the ground.
A short follow-up inspection after the first miles is worthwhile, especially on a performance sedan with low-profile tires. Recheck pressure, look for uneven contact marks, and make sure there is no vibration that could point to balance, wheel condition, or setup issues.
How often should tires on a 2021 Audi S4 be inspected?
Tires on a 2021 Audi S4 should be inspected regularly rather than only at replacement time. A quick visual check for uneven wear, cuts, bulges, cracking, and pressure loss is smart before longer drives, and a more thorough inspection during normal service intervals helps catch problems earlier.
Low-profile performance tires can reveal alignment, suspension, or wheel issues fairly quickly, so wear pattern changes should not be ignored. Routine inspection is especially important if the car sees spirited use, rough pavement, seasonal wheel changes, or long parked periods between drives.
