1998 Porsche sat at an interesting point in the marque’s history, with the air-cooled 911 nearing the end of its run and the newer Boxster broadening Porsche ownership with a mid-engine roadster. Both models were unmistakably Porsche, but they approached performance with different layouts, proportions, and tire needs. Across the 1998 Porsche range, two models use eight distinct tire sizes, with several front and rear sizes shared between the 911 and Boxster while others are model-specific. The practical first step is to confirm your exact model and wheel diameter, then match the correct front or rear size before narrowing your choice to the tire that suits how you drive and present the car.
Which Tire Size Is Right for Your 1998 Porsche
Eight tire sizes appear across 1998 Porsche vehicles, and they vary by model rather than being universal across the full range. Because these sizes span 16-, 17-, and 18-inch wheels, the real decision starts with confirming the correct wheel diameter and whether you are matching a front or rear fitment for a 911 or Boxster. Understanding that distinction before choosing a product saves time and helps ensure the right match.
Year(s): 1998|Fit(s): 911, Boxster|Construction: Radial|Rim: 17 in
205/50R17 is a radial metric size with a 205 millimeter section width, a 50-series aspect ratio, and a 17-inch rim diameter. It is available from BFGoodrich and American Classic with Blackwall and Wide Whitewall sidewall styles, and tube status varies by product because some carry no tube marking while others use a standard radial size description without a TT designation. Shared by both 1998 Porsche 911 and Boxster models, this size suits owners who need a common 17-inch fitment and want to choose between a conventional performance look or a more custom-oriented whitewall presentation.
Year(s): 1998|Fit(s): 911, Boxster|Construction: Radial|Rim: 17 in
255/40R17 is a radial metric size that uses a 255 millimeter section width, a 40-series aspect ratio, and a 17-inch rim diameter. It is available from BFGoodrich, Nitto, and Vredestein in Blackwall form, and speed ratings vary by product with W-rated choices to 168 mph and a Y-rated Vredestein Sprint Plus to 186+ mph. Shared by both 1998 Porsche 911 and Boxster models, this size is a strong choice when your car uses the wider 17-inch rear fitment and you want to compare brand character within the same basic dimensions.
Year(s): 1998|Fit(s): 911, Boxster|Construction: Radial|Rim: 18 in
225/40R18 is a radial metric size with a 225 millimeter section width, a 40-series aspect ratio, and an 18-inch rim diameter. It is available from BFGoodrich and Nitto in Blackwall form, with W-rated products to 112 mph across the range and tubeless status varying by product because the Michelin-style TL marking does not appear on every option in this size. Used by both 1998 Porsche 911 and Boxster models, this size fits buyers running 18-inch front wheels and looking for a modern low-profile radial appearance.
285/30R18 is a radial metric size that combines a 285 millimeter section width, a 30-series aspect ratio, and an 18-inch rim diameter. This size is specific to the 1998 Porsche 911 rather than universal across the year and make. It is the choice to focus on when your 911 carries the widest 18-inch rear fitment and requires a size matched to that model’s broader footprint.
Year(s): 1998|Fit(s): 911, Boxster|Construction: Radial|Rim: 18 in
265/35R18 is a radial metric size with a 265 millimeter section width, a 35-series aspect ratio, and an 18-inch rim diameter. It is available from BFGoodrich and Nitto in Blackwall form, and speed ratings vary by product with W-rated choices to 112 mph and a Y-rated BFGoodrich g-Force Phenom T/A to 186+ mph. Shared by both 1998 Porsche 911 and Boxster models, this size fits owners using a wider 18-inch rear wheel and comparing different performance-oriented radial offerings.
Year(s): 1998|Fit(s): 911, Boxster|Construction: Radial|Rim: 16 in
205/55R16 is a radial metric size with a 205 millimeter section width, a 55-series aspect ratio, and a 16-inch rim diameter. It is available from BFGoodrich and Michelin in Blackwall form, and speed ratings vary by product with W-rated versions to 112 mph and a Michelin SX MXX3 N2 carrying a Y rating to 186+ mph; tubeless status also varies by product because the Michelin version is marked TL. Shared by both 1998 Porsche 911 and Boxster models, this size is a key reference point for cars still using their 16-inch front wheel fitment.
245/45R16 is a radial metric size that uses a 245 millimeter section width, a 45-series aspect ratio, and a 16-inch rim diameter. This size is specific to the 1998 Porsche 911 rather than shared across both Porsche models for the year. It is the size to confirm when your 911 uses the wider 16-inch rear setup and you are matching the original wheel diameter already on the car.
Year(s): 1998|Fit(s): Boxster|Construction: Radial|Rim: 16 in
225/50R16 is a radial metric size with a 225 millimeter section width, a 50-series aspect ratio, and a 16-inch rim diameter. It is available from BFGoodrich and Michelin in Blackwall form, and speed ratings vary by product with W-rated choices to 112 mph and a Michelin Pilot Sport carrying a Y rating to 186+ mph; tubeless status varies by product because the Michelin version is marked TL. This size is specific to the 1998 Porsche Boxster, making it the correct rear-size reference for Boxsters equipped with the 16-inch wheel package.
Two Porsche models are covered for 1998: the 911 and the Boxster. They share several tire sizes, but the overall fitment picture still varies by model, especially once you account for front and rear stagger and the different 16-, 17-, and 18-inch wheel packages. Select your model below to narrow the fitment history and compare the sizes that apply to your specific Porsche.
1998 Porsche 911
The 1998 Porsche 911 represents the final year of the air-cooled 993 generation, a car prized for its blend of classic 911 character and modernized chassis development. Its tire fitments span 16-, 17-, and 18-inch wheels, with distinct front and rear sizes that reflect the 911’s rear-engine layout and wider-tail performance stance.
The 1998 Porsche Boxster helped define Porsche’s late-1990s revival, bringing a mid-engine roadster format that emphasized balance, open-top driving, and a more accessible entry into the brand. Its tire fitments also span 16-, 17-, and 18-inch wheels, with front and rear sizes arranged to suit the Boxster’s lower, more compact proportions and mid-engine handling character.
Twenty-five products are available across eight tire sizes for 1998 Porsche vehicles. 205/50R17 has four products from BFGoodrich and American Classic in radial Blackwall and Wide Whitewall form; 255/40R17 has four from BFGoodrich, Nitto, and Vredestein in radial Blackwall; 225/40R18 has four from BFGoodrich and Nitto in radial Blackwall; 265/35R18 has four from BFGoodrich and Nitto in radial Blackwall; 205/55R16 has four from BFGoodrich and Michelin in radial Blackwall; 225/50R16 has three from BFGoodrich and Michelin in radial Blackwall. Confirm your exact size and wheel package first, since speed ratings and tube markings can vary within the same size.
These answers focus on how 1998 Porsche 911 and Boxster tire sizes differ by model, how the 16-, 17-, and 18-inch fitments relate to one another, and what sidewall, speed-rating, and long-term collector-care details matter before you choose.
Size Basics & Fitment
What tire sizes fit 1998 Porsche vehicles?
1998 Porsche vehicles use eight sizes across the 911 and Boxster ranges: 205/55R16, 225/50R16, 245/45R16, 205/50R17, 255/40R17, 225/40R18, 265/35R18, and 285/30R18. The shared sizes are 205/55R16, 205/50R17, 255/40R17, 225/40R18, and 265/35R18. The 911 alone adds 245/45R16 and 285/30R18, while the Boxster alone uses 225/50R16. Rim diameters span 16, 17, and 18 inches, and published rim-width ranges include 5.5 to 7.5 inches for 205/55R16 and 205/50R17, 6.0 to 8.0 for 225/50R16, 7.5 to 9.0 for 225/40R18, 8.5 to 10.0 for 255/40R17, and 9.0 to 10.5 for 265/35R18.
That means year and make alone are not enough to choose a tire for a 1998 Porsche. You need to identify whether the car is a 911 or Boxster, then confirm whether you are fitting the front or rear axle and what wheel diameter is currently on the car. Many owners encounter mixed fitments because Porsche offered multiple wheel packages, so the actual tire mounted on the wheel is the best first checkpoint before moving on to sidewall style or brand preference.
What does 205/50R17 mean on a 1998 Porsche tire?
On a 1998 Porsche, 205/50R17 is a metric radial size. The 205 is the nominal section width in millimeters, 50 is the aspect ratio, meaning the sidewall height is 50 percent of the section width, R means radial construction, and 17 is the wheel diameter in inches. This size appears on both the 1998 Porsche 911 and 1998 Porsche Boxster. Available versions include BFGoodrich Blackwall radials and an American Classic radial in a wide whitewall style.
For a buyer, that code tells you far more than just diameter. It confirms a low-profile radial on a 17-inch wheel and helps separate it from the 205/55R16 size, which is similar in width but built for a different wheel diameter and profile. If your 1998 Porsche already wears 17-inch wheels, 205/50R17 is the kind of fitment you would expect to see on the front of a staggered setup, but the safest move is still to confirm the exact axle position and wheel size already on the car.
Do all 1998 Porsche models use the same tire size?
No. The 1998 Porsche 911 and 1998 Porsche Boxster share several sizes, but they do not use the exact same full set of tire dimensions. Both models use 205/55R16, 205/50R17, 255/40R17, 225/40R18, and 265/35R18. The 911 also uses 245/45R16 and 285/30R18, while the Boxster uses 225/50R16. That split reflects the fact that Porsche offered different wheel packages and front-to-rear stagger combinations across the two model lines.
The practical takeaway is simple: if you know only that you have a 1998 Porsche, you still need the model before choosing a size. A 911 owner can easily end up looking at a Boxster rear size, and a Boxster owner can just as easily land on a 911-specific rear size that does not belong on the car. Once you identify the model, the next step is verifying whether your wheels are 16, 17, or 18 inches and whether you are replacing front tires, rear tires, or all four.
Buying the Right Tire
What sidewall styles are available for 1998 Porsche tires?
Most 1998 Porsche tire sizes are available in Blackwall form, which is the dominant sidewall style across the 16-, 17-, and 18-inch fitments used by the 911 and Boxster. One exception appears in 205/50R17, where American Classic offers a 0.875-inch Wide Whitewall alongside Blackwall choices from BFGoodrich. The rest of the available sizes center on modern Blackwall performance radials from brands such as BFGoodrich, Nitto, Michelin, and Vredestein.
For most owners, Blackwall is the natural visual match for a late-1990s Porsche and aligns with the understated performance look these cars carried when new. The whitewall option in 205/50R17 is much more of a custom-style choice than an originality play, so it makes sense only if the car has been personalized in that direction. If preserving factory-era appearance matters, compare sidewall styling just as carefully as you compare the size itself.
What brands make tires for 1998 Porsche vehicles?
1998 Porsche fitments are covered by BFGoodrich, American Classic, Nitto, Vredestein, and Michelin, depending on size. BFGoodrich appears across the widest spread of 16-, 17-, and 18-inch applications, while Nitto and Vredestein show up in wider 17- and 18-inch performance sizes. Michelin appears in key 16-inch Porsche sizes, including 205/55R16 and 225/50R16, and American Classic appears in 205/50R17 with a wide whitewall treatment.
Brand choice on a 1998 Porsche usually comes down to matching the wheel size and then deciding what kind of look and driving character you want from the car. Owners trying to preserve a more period-minded Porsche presentation often look closely at Michelin-branded options where available, while others focus on the broader range of modern Blackwall performance radials in BFGoodrich, Nitto, or Vredestein. The important step is making brand comparisons only after the correct front or rear size has been confirmed.
What is the difference between BFGoodrich and Michelin options for 1998 Porsche 16-inch tires?
For 1998 Porsche 16-inch fitments, BFGoodrich and Michelin overlap in 205/55R16 and 225/50R16, but they are not identical in detail. In 205/55R16, BFGoodrich options use a 5.5 to 7.5 inch rim-width range and W speed ratings, while the Michelin SX MXX3 N2 uses the same basic rim-width range and carries a Y speed rating. In 225/50R16, BFGoodrich options use a 6.0 to 8.0 inch rim-width range and W speed ratings, while the Michelin Pilot Sport uses the same rim-width range and carries a Y speed rating.
That makes the comparison less about whether either brand fits and more about which specification better aligns with your car and expectations. A Michelin-branded option can appeal to owners who want a more marque-conscious period feel on a late-1990s Porsche, while BFGoodrich gives broader choice within the same size family. Either way, the first checkpoint is still whether your car takes the 205/55R16 front size, the 225/50R16 Boxster rear size, or another wheel package altogether.
Fitting & Setup
What rim width do 1998 Porsche tires require?
Rim-width requirements for 1998 Porsche tires vary by size. 205/55R16 and 205/50R17 fit rims from 5.5 to 7.5 inches wide, 225/50R16 fits 6.0 to 8.0 inches, 225/40R18 fits 7.5 to 9.0 inches, 255/40R17 fits 8.5 to 10.0 inches, and 265/35R18 fits 9.0 to 10.5 inches. Some brands identify a preferred measuring width inside that range, but the important point is that each tire size has its own acceptable span rather than one universal Porsche wheel width.
That matters any time wheels have been changed, refinished, or swapped between trims and generations. A tire can share the correct diameter but still be wrong for the wheel if the rim is too narrow or too wide for the size you are considering. Before ordering for a 1998 Porsche, confirm the wheel diameter first, then verify the actual wheel width so the tire’s approved range matches the wheel already on the car.
Do 1998 Porsche tires require inner tubes?
Most 1998 Porsche tire choices here are modern radials, and several are explicitly marked TL for tubeless use, including Michelin versions in 205/55R16 and 225/50R16. Other products in the same and neighboring sizes do not carry a tube-type marking in the size description, so tube status can vary by product rather than by wheel diameter alone. None of these Porsche fitments are presented as all tube-type across the board.
The wheel itself still matters, especially on an older car that may have had refinishing work, aftermarket wheels, or prior modifications. If you are replacing tires on a 1998 Porsche, check the exact sidewall marking on the product you intend to use and confirm whether the wheel is designed to run tubeless. If your car has been changed from its original wheel setup, that verification is more important than assuming every radial in the same size uses the same tube practice.
Maintenance, Storage & Longevity
How should I store a 1998 Porsche when the tires are fitted?
A 1998 Porsche stores best in a cool, dry, dark space away from direct sunlight, electric motors, welders, battery chargers, and other ozone-producing equipment that can accelerate sidewall aging. Keep the tires at the correct inflation pressure, avoid long contact with wet concrete or petroleum contamination, and move the car periodically so one patch of tread is not carrying the load for months at a time. These are all radial sizes, so they generally tolerate storage better than older bias-ply designs, but static storage can still create flat-spotting and age-related cracking.
If the car will sit for an extended season, many collectors either roll it a short distance every few weeks or support it in a way that reduces prolonged loading on one section of the tire. A fitted spare should be stored with the same care as the road tires, since it may be the oldest tire on the car and the least often inspected. Good storage habits do more for a low-use Porsche’s tire life than mileage alone ever will.
How long do tires on a 1998 Porsche typically last?
On a 1998 Porsche, tire life should be judged more by age and condition than by mileage, because many 911s and Boxsters see limited annual use. A sound rule is to begin close evaluation once a tire reaches roughly five to seven years of age and to treat around ten years as a serious replacement threshold regardless of tread depth. The DOT date code on the sidewall is the best way to establish age, especially on a collector car that may wear tires installed by a prior owner.
That approach is especially important on a high-performance Porsche, where an older tire may still look acceptable at a glance but has already hardened or lost the flexibility it had when new. A car that spends most of its life indoors can still age out its tires long before it wears them out. If the age is unclear or the sidewalls show cracking, replacement becomes a maintenance decision rather than a tread-depth decision.
How often should tires on a 1998 Porsche be inspected?
Tires on a 1998 Porsche should be checked before every drive and given a closer inspection before any long highway trip or spirited weekend outing. Look for sidewall cracking, cuts, punctures, bulges, uneven tread wear, and pressure loss, and compare the inner and outer shoulders because a staggered Porsche setup can hide wear until it becomes advanced. If your tires are marked tubeless, inspect the valve stems as carefully as the tread and sidewalls.
Regular inspection matters because 911 and Boxster handling is sensitive to tire condition even when the car is not being driven hard. Catching a pressure problem or aging sidewall early is far easier than diagnosing vague steering feel or instability after the fact. A quick visual check before every drive, followed by a more thorough inspection with a pressure gauge and tread-depth check at regular intervals, is the right habit for a 1998 Porsche owner.
Restoration & Authenticity
What tires were originally fitted to the 1998 Porsche 911?
A 1998 Porsche 911 was originally a radial-tire car, not a bias-ply car, and the fitments used here reflect that late-1990s Porsche reality. Depending on wheel package, the 911 uses 16-, 17-, or 18-inch radial sizes, including combinations such as 205/55R16 with 245/45R16, 205/50R17 with 255/40R17, and 225/40R18 with either 265/35R18 or 285/30R18. Michelin and BFGoodrich products both appear in relevant 911 sizes, but confirming the exact original-market combination is best done against factory literature or a knowledgeable Porsche specialist.
For an owner pursuing authenticity, the first priority is getting the correct wheel diameter and front-to-rear stagger for the car’s specific setup. After that, details such as sidewall appearance, brand character, and whether the tire carries a period-appropriate visual profile become more important. Because late-air-cooled 911s often attract especially detail-minded owners, marque clubs and model-specific forums remain useful resources when you want to verify whether your particular wheel package matches how the car left the factory.
Does correct tire fitment matter for showing a 1998 Porsche?
Yes, correct tire fitment matters when a 1998 Porsche is judged seriously, especially on a 911 where wheel and tire presentation is a visible part of the car’s stance and authenticity. Judges and knowledgeable enthusiasts commonly notice whether the car has the right wheel diameter, the correct front-to-rear size relationship, and an appropriate late-1990s sidewall look. A mismatch such as a Boxster-specific rear size on a 911, or a custom whitewall on a car being presented as factory-correct, would stand out immediately.
That does not mean every shown car must use the same brand, but it does mean the overall fitment should make sense for the model and era. If your goal is a factory-style presentation, Blackwall radials are the safer visual direction for a 1998 Porsche than novelty sidewall treatments. Event standards vary, so if the car is headed to PCA judging or a marque-specific concours, compare your intended size and appearance against those event guidelines before finalizing the tire choice.
What is the difference between BFGoodrich and Vredestein options for the 1998 Porsche 255/40R17 size?
In 255/40R17 for a 1998 Porsche, BFGoodrich and Vredestein share the same basic 17-inch radial format and Blackwall appearance, but the details differ. BFGoodrich options include W-rated versions to 112 mph with an 8.5 to 10.0 inch rim-width range, while the Vredestein Sprint Plus carries a Y speed rating to 186+ mph with the same general 8.5 to 10.0 inch rim-width range. Load figures also reach 1,653 pounds in both the Vredestein and the Nitto option within this size family.
That makes the comparison useful for an owner trying to stay within the correct 255/40R17 fitment while weighing how close the tire’s spec profile is to the character they want from the car. On a 1998 Porsche 911 or Boxster using 17-inch rear wheels, the choice is not about changing fitment but about selecting the product that best matches the car’s intended use and presentation. Keeping the right size on the right axle remains more important than chasing small spec differences alone.
Safety & Road Use
Are 1998 Porsche tires safe for highway driving?
Yes, 1998 Porsche tires in these sizes can be suitable for highway driving when they are the correct size for the car, properly inflated, in sound condition, and used within their speed-rating limits. Many options here carry W ratings to 168 mph, while some 16-, 17-, and 18-inch products carry Y ratings to 186+ mph. Those ceilings are well beyond normal U.S. highway use, and on a 1998 Porsche the car’s alignment, suspension condition, brakes, and age-related mechanical health usually matter more in ordinary road driving than the raw speed symbol itself.
What matters most is not choosing the highest letter automatically, but choosing a fresh tire in the correct front or rear size and keeping it in good condition. A Y-rated tire does not compensate for old dampers, worn suspension bushings, or an aging brake system on a late-1990s sports car. Before any longer highway trip, verify pressure, inspect the tire surfaces carefully, and make sure the car tracks correctly rather than relying on speed-rating numbers alone.
What inflation pressure should I use for 1998 Porsche tires?
Inflation pressure on a 1998 Porsche should follow the car’s factory recommendation for its exact wheel and tire package, while also staying within the tire manufacturer’s maximum load-and-pressure limits for the specific tire you choose. Several sizes here include rated load and pressure figures, such as 205/50R17 up to 1,433 pounds at 50 psi, 255/40R17 up to 1,653 pounds at 50 to 51 psi, 225/40R18 up to 1,389 pounds at 50 to 51 psi, 265/35R18 up to 1,609 pounds at 50 to 51 psi, 205/55R16 up to 1,477 pounds at 50 psi, and 225/50R16 up to 1,389 pounds at 51 psi.
Those numbers are tire-capacity limits, not a universal setting for every 1998 Porsche. A 911 and a Boxster can call for different cold pressures, and front and rear pressures often differ on staggered sports-car fitments. The right approach is to start with the factory vehicle specification for your exact model and wheel package, then confirm that the tire you selected is being used within its own load-and-pressure envelope rather than transferring one size’s pressure assumptions to another.
What should I check before taking a 1998 Porsche on a longer drive?
Before taking a 1998 Porsche on a longer drive, inspect all four tires and the spare for age, cracking, tread depth, punctures, bulges, and pressure. Pay special attention to the inside shoulders on staggered fitments, because wear can hide there on both 911 and Boxster applications. If your tires or spare use tubeless markings, inspect the valve stems as well, and make sure the wheel diameters and axle positions still match the sizes installed on the car.
Tires are only one part of the pre-trip picture on a late-1990s Porsche, but they are the part that most directly affects ride quality, steering response, and stability at speed. A quick check should be paired with a broader look at fluid levels, brakes, and suspension condition before a long outing. On a performance car that may spend long stretches in storage, that simple routine can prevent the most common age-related road issues before they start.
