2018 Audi Tire Fitment Guide

2018 Audi vehicles span 22 distinct tire sizes: 225/45R17, 225/50R17, 225/40R18, 245/40R18, 245/45R18, 235/35R19, 245/35R19, 255/35R19, 255/40R19, 255/45R19, 265/35R19, 295/35R19, 255/35R20, 265/35R20, 245/30R20, 305/30R20, 275/30R20, 255/30R20, 265/40R20, 275/35R21, and 275/30R21. They are not shared across the whole make. A3-based cars use 17-, 18-, and 19-inch sizes, A4 and A5 families mix 17 through 19 inches, A6 and A7 models move into 18 through 20 inches, and flagship or RS applications reach 21 inches.

That means a 2018 Audi buyer should start with the exact model name before looking at tread design or brand. Some sizes are shared among related models, such as 245/40R18 across several A4-, A5-, S-, and TT-based cars, while others are highly specific, such as 245/30R20 on the R8 or 255/45R19 on the A8 Quattro. Where rim-width guidance is available, it also varies by size, so wheel diameter alone is only part of the match.

On a 2018 Audi tire, 225/40R18 is a modern metric radial size. The 225 is the nominal section width in millimeters, 40 is the aspect ratio, meaning the sidewall height is 40 percent of the section width, R means radial construction, and 18 is the wheel diameter in inches. That size appears on A3, A3 Quattro, A3 Sportback e-tron, and S3 models.

Knowing how to read the code helps separate similar-looking Audi fitments that are not interchangeable. A 225/40R18 and a 225/45R17 may both belong to the A3 family, but they mount on different wheel diameters and carry different overall proportions. If your car already has wheels fitted, compare the sidewall marking on the tire to the exact code, then confirm that the model and wheel package agree before choosing a replacement.

No. 2018 Audi models use a wide spread of sizes that change by model, wheel package, and performance level. Compact A3-family cars use sizes such as 225/45R17, 225/40R18, and 235/35R19, while an A8 Quattro can use 255/45R19, 265/40R20, or 275/35R21. The R8 also stands apart with staggered front and rear fitments including 245/30R20, 245/35R19, 295/35R19, and 305/30R20.

That variation matters because Audi used the same brand family naming across very different vehicles in 2018. An A4 owner, an S7 owner, and an R8 owner are all shopping within the same model year, but their tires differ in wheel diameter, width, and sidewall height. If you know only that you have a 2018 Audi, identify the exact model and verify the tire size on the car before narrowing the search any further.

Most supported 2018 Audi sizes are available in Blackwall form, which matches the contemporary factory look Audi used across its sedans, coupes, hatchbacks, and sports cars. A few larger performance sizes add custom-style sidewalls: 265/35R20 is available in Blackwall, Redline, and RWL, and 305/30R20 is available in Blackwall, RWL, and Redline. Those sizes apply to A7 Quattro and S7 in the 265/35R20 fitment and to the R8 in 305/30R20.

For an OEM-style appearance, Blackwall is the natural choice on a 2018 Audi. Redline and raised white letter styling create a distinctly non-factory visual statement, so they make more sense for a personalized build than for an appearance-correct late-model restoration. If sidewall appearance matters as much as fitment, choose the size first, then confirm whether that size offers only Blackwall or also includes more custom-oriented options.

2018 Audi coverage includes BFGoodrich, Nitto, M&H Racemaster, and Pro-Trac, depending on the size. Many common Audi sizes such as 225/40R18, 225/45R17, 245/40R18, 245/45R18, and 265/35R19 are available from BFGoodrich and Nitto. M&H Racemaster appears in 245/40R18 through a drag-radial application, while Pro-Trac adds Redline and RWL choices in 265/35R20 and 305/30R20.

Brand choice on a 2018 Audi is usually less about one make-wide answer and more about which exact size your model uses. The A3, A4, A5, A6, and several S-model fitments tend to have the broadest overlap between BFGoodrich and Nitto, while more specialized or custom-style sidewall options cluster in certain larger sizes. Once the size is confirmed, compare brands by sidewall look, speed rating, and any rim-width guidance attached to that specific tire.

For several 2018 Audi sizes, BFGoodrich g-Force Phenom T/A and Nitto NT555 G2 overlap in fitment but differ in the details attached to each size. In 235/35R19, the BFGoodrich carries a Y speed rating up to 186 mph and a stated 8.0 to 9.5-inch rim-width range, while the Nitto carries a W rating up to 168 mph. In 245/45R18, the BFGoodrich also carries a Y rating, while the Nitto is W-rated and specifies a 7.5 to 9.0-inch rim-width span centered on 8.0 inches.

That does not automatically make one tire right for every 2018 Audi driver, but it does show why comparing within the exact size matters. If your priorities include a particular speed rating ceiling or a clearly stated rim-width match, those details can separate two tires that otherwise appear very similar at a glance. Use the vehicle's actual tire size first, then compare the series-level differences only within that confirmed size.

Rim width on 2018 Audi tires depends entirely on size. Examples include 225/45R17 at roughly 7.0 to 8.5 inches on some tires and up to 8.5 to 10.0 inches on another, 245/40R18 at 8.0 to 9.5 inches, 245/45R18 at 7.5 to 9.0 inches, 255/35R19 at 8.5 to 10.0 inches, and 265/35R20 at 9.0 to 10.5 inches where stated. Some products in the same nominal size also give a preferred measuring width within that broader range.

That is why wheel diameter by itself is never enough on a 2018 Audi, especially on sport or RS models where wide wheels are common. If your car has aftermarket wheels, confirm both the tire size and the wheel width before choosing a replacement. Staying within the stated range for the exact tire helps preserve the intended tread shape and keeps the fitment in line with the tire maker's recommendations.

The supported 2018 Audi products are modern radial tires intended for tubeless use, and one 245/40R18 BFGoodrich product even marks that directly with a TL notation. Other tires omit the TL mark in the size string but still follow the same late-model radial tubeless pattern typical of these fitments. No tube-type markings appear among the covered sizes, and these are all modern 17- through 21-inch Audi applications rather than vintage tube-era fitments.

For most 2018 Audi owners, that means the focus should be on the condition of the wheel, valve stem, and bead seat rather than on sourcing inner tubes. If the car wears damaged wheels, unusual aftermarket rims, or a tire with a sidewall marking you want to verify, inspect the exact tire and wheel combination before mounting. A clean, undamaged tubeless wheel is the expected setup for these Audi sizes.

No single wheel fits all 2018 Audi tire sizes because the lineup uses 17-, 18-, 19-, 20-, and 21-inch diameters, often with different widths as well. A 225/45R17 A3-family tire cannot mount on an 18-inch A4 wheel, and a 275/30R21 RS7 tire cannot mount on a 20-inch S7 wheel. The R8 adds another layer because it uses staggered sizes with dedicated front and rear fitments.

Original 2018 Audi wheels can usually be reused only within the exact size family they were built to accept. If you are replacing tires on the factory wheels, match the sidewall code already on the car and then confirm the wheel width against the tire's acceptable range where that information is available. If you are changing wheel diameter, treat it as a full wheel-and-tire fitment decision rather than a simple tire replacement.

A 2018 Audi that sits for long periods should be stored in a cool, dry space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can age rubber faster. Keep the tires clean, maintain correct inflation, and move the car periodically so the same section of tread is not carrying the load month after month. Modern radials resist flat-spotting better than older bias-ply designs, but long static storage can still harden the contact patch and stress the sidewalls.

If the car will be parked through a season, many owners either roll it occasionally or place it on stands in a way that follows the vehicle maker's support points. That approach reduces sustained load on one area of the tire and can also protect expensive wheels from cosmetic damage during storage. A breathable indoor cover helps the car, but the tire's real enemies are heat, sunlight, underinflation, and long immobility.

On a low-mileage 2018 Audi, tire age usually matters more than tread wear. A practical rule is to begin evaluating tires closely once they reach about five to seven years of service, then consider replacement around the 10-year mark regardless of remaining tread. The DOT date code on the sidewall gives the week and year of manufacture, which is the best reference point for an enthusiast car that may not accumulate many miles.

That timeline becomes especially important on performance-oriented Audi sizes with short sidewalls, because the car can still feel normal around town even when the rubber has aged beyond its prime. Storage conditions, heat cycles, and underinflation can shorten useful life further. If a 2018 Audi has sat for extended periods, inspect age and condition before assuming the tires are sound simply because the tread looks deep.

Tires on a 2018 Audi should be checked before every drive and inspected more thoroughly before any longer trip. Look for cracking, cuts, bulges, embedded debris, uneven wear, and any sign that the tire is losing pressure. Low-profile Audi fitments can hide damage on the inner sidewall, so a quick look at the outside sidewall alone is not enough.

A monthly pressure check is a good baseline for a regularly driven car, while an enthusiast Audi that spends time parked should also be inspected before it returns to the road after storage. Pay attention to vibration, steering pull, or new road noise, since those can point to wear or internal damage that is not obvious at a glance. On staggered cars such as the R8, inspect front and rear tires separately because each axle uses a different size.

Yes, the supported 2018 Audi tires are highway-capable modern radials, and the speed ratings shown across the covered sizes are generally W and Y. A W rating carries a ceiling of 168 mph, while a Y rating carries a ceiling of 186 mph. Those numbers exceed normal U.S. highway use by a wide margin, so for everyday driving the car's alignment, suspension condition, inflation pressure, and overall mechanical health matter at least as much as the rating printed on the tire.

The important detail is that the exact rating can vary within the same size. A 235/35R19, 245/45R18, 255/35R20, 255/40R19, 265/35R20, or 265/35R19 may be offered in both W- and Y-rated forms depending on brand and series. If your 2018 Audi is driven hard, used for long interstate runs, or maintained to a high-performance standard, confirm the exact speed rating on the tire you choose rather than assuming every product in that size is identical.

Inflation pressure for a 2018 Audi should follow the vehicle's factory specification for the exact model, axle load, and tire size, using the door-jamb placard or owner's manual as the starting point. Tire-specific load and pressure figures also appear on some supported products: for example, 225/40R18 appears up to 1,389 pounds at 50 psi, 225/50R17 up to 1,653 pounds at 50 psi, 245/45R18 up to 1,764 pounds at 50 psi, and 255/35R19 includes products marked as high as 2,041 pounds at 50 psi.

Those figures are maximum tire ratings, not a universal running pressure for every 2018 Audi. Audi's recommended cold inflation setting is the correct day-to-day reference because it reflects the vehicle's weight distribution, ride tuning, and intended use. If you change tire brand or load index, compare the tire's sidewall information with the car's factory guidance instead of transferring one size's pressure habit to another.

Before a longer trip in a 2018 Audi, inspect each tire for cracking, punctures, cuts, bulges, uneven wear, and proper cold inflation. Verify that the exact size on the car matches the wheel and axle position, especially on staggered applications such as the R8 and on model-specific high-performance fitments in the RS and S lines. The spare, if equipped, also deserves inspection for age and pressure rather than being treated as an afterthought.

Tires are only one part of the preparation, but they are the part in direct contact with the road and the easiest to overlook on a late-model enthusiast car that is not driven daily. A pre-trip check should also include brakes, fluid levels, and suspension condition, since a mechanically compromised car can overwork even a healthy set of tires. Catching a pressure loss or sidewall problem in the garage is far better than finding it hours from home.