The 2018 Audi A3 sits in the modern compact luxury segment with the crisp road manners, tidy proportions, and premium everyday usability that made the A3 such a strong fit for buyers who wanted Audi refinement in a smaller package. Tire selection on this car is closely tied to trim and wheel package, with 225/45R17, 225/40R18, and 235/35R19 radial sizes all appearing across the lineup. That means the decision is less about vintage-style construction and more about confirming the exact sub-model and wheel diameter, then choosing among available radial series, brands, and sidewall treatments. For a stock car, the right tire starts with matching the original size strategy before comparing appearance and performance character.
Which Tire Size Is Right for The 2018 Audi A3
The 2018 Audi A3 uses three primary tire sizes, and the correct one depends on the specific sub-model and wheel diameter. All three are radial metric sizes, but they are split across 17-inch, 18-inch, and 19-inch rims, so the first step is confirming the exact trim and checking the wheels currently on the car. Once that is settled, the choice becomes which tire series, brand, and sidewall style best matches the car’s intended use.
Fit(s): Premium Cabriolet, Premium Plus Cabriolet, Premium Plus Sedan, Premium Sedan, Prestige Cabriolet, and Prestige Sedan
Construction: Radial|Rim: 18 in
225/40R18 is a metric radial size with a 225-millimeter section width, a 40-series aspect ratio, and fitment on an 18-inch rim. On the 2018 Audi A3, it serves as one of the central wheel-package sizes and keeps the focus on modern radial construction rather than vintage sizing conventions. Available choices in this size include BFGoodrich and Nitto offerings in series such as g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and NT555 G2, all in blackwall form. This size is the one to evaluate when the car is already equipped with 18-inch wheels and the goal is to preserve the intended wheel-and-tire relationship.
225/45R17 is a metric radial size that combines a 225-millimeter section width with a 45-series profile on a 17-inch rim. For the 2018 Audi A3, it represents the 17-inch fitment path and gives buyers a distinct starting point from the 18-inch and 19-inch packages used elsewhere in the range. Product selection in this size includes BFGoodrich, Nitto, and Pro-Trac, with blackwall, raised white letter, and redline sidewall treatments available across several radial series. It is the right size to examine when the car has 17-inch wheels and the buyer wants to compare both performance-oriented and appearance-driven options.
Fit(s): Premium Plus Cabriolet, Premium Plus Sedan, Prestige Cabriolet, and Prestige Sedan
Construction: Radial|Rim: 19 in
235/35R19 is a metric radial size with a 235-millimeter section width, a lower 35-series profile, and a 19-inch rim diameter. On the 2018 Audi A3, this size belongs to the larger wheel-package fitment used on certain sub-models, so it should not be assumed for every car in the lineup. Available options in this size include blackwall radial tires from Nitto and BFGoodrich, including NT555 G2 and g-Force Phenom T/A. This size is the one to confirm when the car wears 19-inch wheels and the owner wants to stay aligned with that larger-diameter setup rather than stepping into a different wheel package.
Sub-model fitment on the 2018 Audi A3 is not the same across the full range, because different sedan and cabriolet trims pair with different wheel diameters. Checking the exact trim matters here, since the car may use a 17-inch, 18-inch, or 19-inch tire package depending on configuration.
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2018 Audi A3 Premium Cabriolet
The 2018 Audi A3 Premium Cabriolet uses either a 225/45R17 or 225/40R18 radial tire depending on its wheel setup. That makes wheel confirmation especially important before choosing a replacement, since both sizes belong to this sub-model but fit different rim diameters.
The 2018 Audi A3 Premium Plus Cabriolet uses 225/40R18 or 235/35R19 radial tires, placing it in the larger-wheel side of the A3 lineup. Tire selection starts with confirming whether the car is on 18-inch or 19-inch wheels, then comparing the available blackwall radial options in the matching size.
The 2018 Audi A3 Premium Plus Sedan also uses either 225/40R18 or 235/35R19 radial tires. That means the right replacement depends on the actual wheel package on the car, not simply the model name, especially if wheels have been changed since new.
The 2018 Audi A3 Premium Sedan uses 225/45R17 or 225/40R18 radial tires. Buyers with this sub-model should verify whether the car is carrying its 17-inch or 18-inch wheel setup before comparing brands, sidewall styles, and tire series.
The 2018 Audi A3 Prestige Cabriolet uses either 225/40R18 or 235/35R19 radial tires. For this trim, the tire decision is tied directly to wheel diameter, so replacing by size on the sidewall is the safest way to stay aligned with the current setup.
The 2018 Audi A3 Prestige Sedan uses 225/40R18 or 235/35R19 radial tires. That gives owners a straightforward path once the wheel diameter is confirmed, with blackwall radial choices available in both sizes from established performance-oriented brands.
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 A3 Tires for Sale
Available 2018 Audi A3 tire choices center on radial fitments in 17-, 18-, and 19-inch sizes from BFGoodrich, Nitto, and Pro-Trac. Buyers can compare series such as g-Force, NT555 G2, and Street Pro III, with blackwall, raised white letter, and redline treatments depending on size.
Common 2018 Audi A3 tire questions usually come down to identifying the right size for the trim and wheel package, then comparing radial options by brand, sidewall style, and road-use priorities. The details below focus on fitment, selection, and practical checks before driving.
Tire Size & Fitment
What tire size fits a 2018 Audi A3?
The 2018 Audi A3 uses three primary tire sizes: 225/45R17, 225/40R18, and 235/35R19. All are radial metric sizes, and the correct one depends on the specific sedan or cabriolet sub-model along with the wheel package installed on the car.
The most important step is checking the actual tire sidewall and confirming the wheel diameter before ordering replacements. Some A3 trims share more than one approved size, so selecting by model name alone can lead to the wrong tire if the car has a different wheel package or has been changed from stock.
What size rim does a 2018 Audi A3 use?
A 2018 Audi A3 may use 17-inch, 18-inch, or 19-inch rims depending on the trim and tire size. The 225/45R17 fits a 17-inch rim, the 225/40R18 fits an 18-inch rim, and the 235/35R19 fits a 19-inch rim.
Rim diameter is the first fitment checkpoint because each tire size is built around a specific wheel diameter and cannot be mixed across rim sizes. Checking wheel width is also worthwhile when comparing products, since some tires in the same size carry different recommended rim-width ranges.
Do all 2018 Audi A3 sub-models use the same tire size?
No, 2018 Audi A3 sub-models do not all use the same tire size. Premium Sedan and Premium Cabriolet can use 225/45R17 or 225/40R18, while Premium Plus and Prestige sedan and cabriolet versions use 225/40R18 or 235/35R19.
That variation means the exact trim helps narrow the choices, but the wheel diameter on the car still needs to be confirmed before replacing tires. Looking at the current sidewall marking is the quickest way to avoid confusion, especially on cars that may have been fitted with a different wheel package over time.
Choosing the Right Tire
What should I consider when choosing a 2018 Audi A3 tire?
Start with the correct size for the car’s trim and wheel diameter, since the 2018 Audi A3 uses 225/45R17, 225/40R18, or 235/35R19 depending on configuration. After size is confirmed, compare radial tire series, brand, sidewall style, and any rim-width or load details that matter to the way the car is driven.
A stock daily driver may call for a different emphasis than a fair-weather car or one built around a particular visual style. It helps to match the new tire to the car’s current wheel setup, review any load figures that are stated with pressure, and avoid choosing on appearance alone if the specification differs from the car’s needs.
What sidewall styles are available for 2018 Audi A3 tires?
Sidewall style depends on tire size. Blackwall is available across the 17-inch, 18-inch, and 19-inch A3 fitments, while the 225/45R17 size also has raised white letter and redline choices through the Street Pro III series.
That matters if appearance is part of the decision, because the same vehicle may look very different depending on sidewall treatment. A buyer using 17-inch wheels has more visual variety, while 18-inch and 19-inch choices stay focused on blackwall performance-style presentation.
What brands offer tires for the 2018 Audi A3?
Tires for the 2018 Audi A3 are available from BFGoodrich, Nitto, and Pro-Trac, depending on the size. BFGoodrich appears in all three primary sizes, Nitto appears in the 17-, 18-, and 19-inch sizes, and Pro-Trac is available in 225/45R17.
Brand choice should come after confirming the exact tire size on the car, because not every brand spans every A3 fitment in the same way. Once size is settled, it becomes easier to compare tire series, sidewall presentation, stated rim-width range, and other details that shape how each option fits the intended use.
Restoration & Appearance
How does tire construction affect the appearance of a 2018 Audi A3?
On a 2018 Audi A3, construction does not create a bias-ply-versus-radial appearance decision because the primary fitments are all radial. The visual difference instead comes from wheel diameter, profile, and sidewall treatment, especially where 225/45R17 offers blackwall, raised white letter, and redline choices.
A 17-inch setup can take the car in a more customized visual direction, while the 18-inch and 19-inch sizes stay centered on blackwall modern-performance styling. Keeping the original size family for the wheel package usually preserves the intended stance better than mixing in a different diameter simply for appearance.
Does correct tire fitment matter for a 2018 Audi A3 restoration or preservation project?
Yes, correct tire fitment still matters on a 2018 Audi A3 even though it is a modern car rather than a traditional restoration-era vehicle. Staying with the proper 17-, 18-, or 19-inch size for the exact trim and wheel package helps preserve the car’s proportions, drivability, and overall presentation.
Owners focused on preservation should begin with the size already associated with the car’s wheel setup, then compare available series and sidewall styles within that fitment. If authenticity to original delivery matters, vehicle-specific documentation and original wheel information are worth checking before changing size or appearance.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 Audi A3?
Yes, modifications can affect tire fitment on a 2018 Audi A3. Aftermarket wheels, altered wheel width, offset changes, lowering, suspension work, or body modifications can all change how a 225/45R17, 225/40R18, or 235/35R19 tire sits in the wheelwell.
A car that no longer has its original wheel package should be checked carefully before replacement tires are chosen by trim alone. Verifying wheel diameter, measuring wheel width where possible, and checking steering and fender clearance can prevent problems that would not appear on a stock A3 using the same nominal tire size.
What should I inspect before driving a 2018 Audi A3 on new tires?
Before driving a 2018 Audi A3 on new tires, inspect basic installation points and the vehicle’s general tire-related condition. Check that all four tires match the intended size, confirm inflation, and look over the wheels, valve stems, tread surfaces, and sidewalls for any obvious damage or mounting issues.
It is also smart to make sure the tires clear properly at full steering lock and over suspension movement, especially if the car uses non-stock wheels or has been lowered. A short, careful test drive can reveal vibration, rubbing, or pressure loss early before the car is taken on a longer trip.
How often should tires on a 2018 Audi A3 be inspected?
Tires on a 2018 Audi A3 should be inspected regularly rather than only when they look worn. Frequent visual checks for cuts, bulges, uneven wear, embedded debris, or pressure loss are a good habit, particularly on a car using lower-profile 18-inch or 19-inch fitments where road impacts can be harder on tires and wheels.
A more thorough inspection is worthwhile before seasonal use, longer trips, or any drive after the car has been parked for extended periods. Paying attention to tread condition, sidewall aging, and air retention helps catch problems early and is especially important if the car is driven less often than a typical daily commuter.
