1958 Porsche Tire Fitment Guide

1958 Porsche vehicles use four sizes split between two models. The 1958 Porsche 356 A uses 155R15 in radial form and 560-15 in bias-ply form, while the 1958 Porsche Carrera uses 165R15 in radial form and 590-15 in bias-ply form. All four sizes mount on 15-inch wheels, and published rim-width guidance appears within the available products: 155R15 fits 4.00 to 5.50-inch rims where listed, 560-15 fits 4.5 to 5.50-inch rims depending on product, 165R15 fits 4.50 to 6.00-inch rims, and 590-15 fits 4.00 to 4.50-inch rims where listed.

That means year and make alone are not enough to choose correctly. Start by identifying whether your car is a 356 A or a Carrera, then decide whether you want the model's radial size or its bias-ply size. Once you have those two points settled, compare the wheel's actual width to the tire manufacturer's approved range before making a final selection.

On a 1958 Porsche, 560-15 is a numeric bias-ply size. The 5.60 portion refers to the tire's nominal section width, and the 15 identifies the wheel diameter in inches. For 1958 Porsche applications, this size belongs to the 356 A and is offered in classic bias-ply construction with whitewall variations rather than as a metric radial.

A buyer looking at 560-15 is usually deciding around appearance and period feel as much as fitment. It keeps you in the 356 A's bias-ply family and gives you a choice of narrow or wide whitewall styling, depending on the look you want. Before ordering, match the wheel width to the specific product because some versions are listed for a fixed 4.5-inch rim while others allow a broader range.

On a 1958 Porsche, 155R15 is a metric radial size used on the 356 A. The 155 indicates a nominal section width of 155 millimeters, the R identifies radial construction, and the 15 is the wheel diameter in inches. Because no aspect ratio is stated, it falls into the traditional Euro-metric convention commonly treated as an 80-series radial.

That code matters because 155R15 is not interchangeable with the Carrera's 165R15 just because both fit 15-inch wheels. It is the 356 A's radial-size path, and the products within it differ in tube status and speed rating. If you are moving from a bias-ply setup to a radial one, confirm the exact sidewall marking and wheel-width suitability rather than choosing by diameter alone.

For a 1958 Porsche 356 A, the choice between 155R15 and 560-15 is a choice between radial and bias-ply construction within the correct model family. The 155R15 radial is available in blackwall form, with some products carrying T or H speed ratings and either tube-type or tubeless construction depending on the version. The 560-15 is the 356 A's bias-ply option and is offered in narrow whitewall and wide whitewall styles from Firestone and US Royal.

A 356 A owner usually chooses 560-15 when the goal is a more traditional visual presentation and period-style construction, while 155R15 serves owners who want to stay with the model's radial-size option. The key is not to compare them as universal Porsche sizes, because both belong only to the 356 A. Once you decide on construction style, narrow the selection by sidewall look, wheel width, and any tube or speed-rating requirement.

1958 Porsche tires are available in several sidewall treatments, but the choices depend on size. The 155R15 radial for the 356 A is offered in blackwall only, while the 560-15 bias-ply for the same model is available in narrow whitewall and wide whitewall versions. The Carrera's 165R15 radial appears in blackwall, narrow whitewall, and wide whitewall forms, and the 590-15 bias-ply is available in blackwall and wide whitewall styles.

Sidewall style is often a restoration or presentation decision more than a fitment one. Blackwalls tend to align with a restrained sports-car look, while whitewalls create a more period-styled appearance that some owners prefer for show presentation or a specific market look. The safest approach is to confirm what image you want the car to project and then choose within the size that belongs to your exact model.

Several brands cover the 1958 Porsche range, with each size drawing from a different mix. The 356 A's 155R15 radial is available from Firestone and Michelin, and its 560-15 bias-ply is offered by Firestone and US Royal. The Carrera's 165R15 radial comes from Coker Classic, American Classic, Firestone, and BFGoodrich, while the 590-15 bias-ply is available from BFGoodrich and Avon.

Brand choice should come after you confirm the correct size for the model. Once that is settled, compare each brand's available sidewall style, any stated load and pressure figures, and whether the tire is tube-type or tubeless when that detail appears. On a collector Porsche, the right brand is usually the one that matches the car's intended look and the way you plan to use it, rather than the one with the broadest catalog footprint.

Published rim-width guidance for 1958 Porsche tires varies by size. The 356 A's 155R15 radial is listed for 4.00 to 5.50-inch rims where that measurement appears, and the 560-15 bias-ply ranges from 4.5 inches on some products to 4.50 to 5.50 inches on others. The Carrera's 165R15 radial is listed for 4.50 to 6.00-inch rims, while the 590-15 bias-ply is listed for 4.00 to 4.50-inch rims on the products that publish a width range.

Those ranges are important because a tire can share the same wheel diameter but still be wrong for the wheel's width. Measure the wheel you actually have rather than relying on assumptions about what should be on the car. That is especially helpful on restored Porsches that may have had wheels changed over the years.

Inner-tube requirements on 1958 Porsche tires depend on the exact size and product. Within 155R15, tube status varies by product: Michelin XAS appears in tube-type form, Michelin XAS-FF appears in tubeless form, and Michelin X is also marked tubeless. The other listed sizes do not consistently show TT or TL markings across every product entry, so the exact sidewall marking on the tire you choose is the detail to confirm.

That matters because tube use is a product-level decision, not just a year-and-make decision. If your wheel type or restoration plan points you toward a tube-type setup, check the individual tire's construction marking before purchase and match it to the wheel's condition and design. When replacing older tires, inspect valve stems and the spare at the same time so the full setup is ready for service.

All 1958 Porsche tire sizes in this range use a 15-inch rim diameter, so they share wheel diameter compatibility at that level. That does not mean every 15-inch wheel works with every size across both models, because the approved rim-width ranges are different. The 165R15 radial and 590-15 bias-ply used on the Carrera have different width requirements than the 356 A's 155R15 and 560-15 pair.

A buyer should treat wheel diameter as only the first checkpoint. The next step is to match the wheel's actual width to the approved range for the exact tire size being considered, and to stay within the size family assigned to the correct model. That avoids forcing a model-specific tire onto a wheel that is the right diameter but the wrong width.

A stored 1958 Porsche should be kept in a cool, dry space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can accelerate rubber aging. Keep the tires properly inflated, move the car periodically if practical, and avoid leaving it parked for long stretches on damp concrete or contaminated surfaces. Bias-ply tires tend to flat-spot more readily during static storage, while any collector tire can suffer sidewall aging if exposed to heat and ozone over time.

Owners who store a 356 A or Carrera for extended periods often use tire cradles or support stands to reduce prolonged casing stress, especially if the car is not driven often. A brief inspection before the next drive should include pressure, sidewall condition, and any visible deformation that developed in storage. Good storage habits preserve both appearance and drivability better than simply covering the car and leaving it untouched.

Tires on a 1958 Porsche usually age out before they wear out, because collector cars often see limited annual mileage. A good rule is to evaluate them closely once they reach about five to seven years of age and to consider replacement as they approach ten years, even if tread depth still looks acceptable. The DOT date code on the tire sidewall is the reliable way to determine age rather than relying on how fresh the car feels on occasional drives.

That time-based approach is especially important on vintage sports cars that may spend long periods parked between uses. Rubber hardens, internal materials age, and old tires can become less trustworthy even when they still hold air and look presentable at a glance. If you are preparing a 1958 Porsche for touring, replacing old tires on age alone is often wiser than waiting for visible wear to force the decision.

Tires on a 1958 Porsche should be inspected before every drive and again before any longer outing. Look for sidewall cracking, cuts, bulges, unusual tread wear, and signs that the tire is losing pressure between uses. If your chosen tire is tube-type, include the valve stem and tube-related sealing condition in the inspection routine, because slow air loss can come from parts other than the tread area itself.

Frequent inspection makes sense because many collector cars sit longer than modern daily drivers and can develop issues while parked. A short local drive may not reveal a problem that becomes serious at sustained road speed or when the car is loaded with luggage. Five minutes in the garage before departure is often enough to catch a tire issue early.

A 1958 Porsche 356 A belongs to an era when bias-ply construction was still the expected original-equipment baseline, even as radial technology was gaining ground in Europe. Within the current fitment range for the 356 A, 560-15 represents the bias-ply size and 155R15 represents the radial-size option. No original-equipment brand should be assumed from size alone, because market delivery, period replacement history, and restoration goals can all influence what is considered correct.

For a restoration aimed at historical accuracy, size, construction type, and sidewall appearance matter together rather than as separate decisions. A marque specialist or 356 club is the right place to verify market-specific expectations for a particular car, especially if you are preparing it for judging. Once that goal is clear, choose the tire that supports the desired authenticity level without guessing from modern replacement habits.

Correct tire fitment does matter when showing a 1958 Porsche, especially at marque-oriented events where judges and knowledgeable enthusiasts pay attention to size, construction type, and sidewall appearance. A 356 A wearing its proper model-specific size will generally present more credibly than one fitted with a Carrera-only size, and the same model-specific principle applies in reverse. Construction also matters, because a modern radial can look different from a period-style bias-ply even when both fit the car.

The practical takeaway is to define your target before choosing the tire. A touring-oriented car may justify one decision, while a concours-minded car may call for a different construction and sidewall look. Event standards vary, so confirming expectations with the relevant Porsche club or judging body is more useful than assuming all shows view authenticity the same way.

For a 1958 Porsche 356 A in 155R15, Michelin XAS and Michelin XAS-FF are both H-rated blackwall radials with a 130 mph speed ceiling and both are listed for 4.00 to 5.50-inch rims. The key distinction shown in the available specifications is tube status: Michelin XAS appears as 155HR15 82H TT, while Michelin XAS-FF appears as 155HR15 82H TL. Both also carry the same listed weight in this fitment.

That means the choice is less about size or speed capability and more about how the tire integrates with your wheel and setup plan. If you are sorting out a restoration or wheel arrangement that favors one tube strategy over the other, that difference becomes important quickly. It is a good example of why two tires with nearly identical size markings still deserve a careful sidewall-by-sidewall comparison.

1958 Porsche tires can be appropriate for highway use when they are the correct size for the model, in sound condition, and operated within their ratings. Among the listed products, 155R15 includes T-rated tires with a 118 mph ceiling and H-rated tires with a 130 mph ceiling, while the 590-15 Avon option is also H-rated at 130 mph. Other sizes in the range do not always show a speed letter in the available specifications, so the exact tire sidewall remains the final authority.

On a late-1950s Porsche, overall roadworthiness depends on more than the tire alone. Brakes, suspension condition, alignment, wheel integrity, and how long the car has been sitting all matter at least as much as the printed speed symbol during normal highway driving. A fresh, properly fitted tire is part of a safe setup, but it should be considered alongside the mechanical condition of the entire car.

Inflation pressure for 1958 Porsche tires should be confirmed from the vehicle literature and the tire's own published rating rather than transferred from one size to another. The available tire specifications show 155R15 products rated at 1045 pounds at 44 psi on one Firestone version, 560-15 products rated at 970 pounds at 32 psi, 165R15 products rated at 1168 pounds at 35 psi or 1170 pounds at 36 psi depending on product, and 590-15 products rated at 1050 pounds at 32 psi, with one Avon listing a 1,018-pound load figure.

Those numbers are tire ratings, not automatic vehicle settings. The correct operating pressure for your specific 356 A or Carrera should reflect the car's recommended pressures, tire construction, and intended use. If you change from one construction type to another, revisit pressure guidance instead of carrying over the previous tire's settings by habit.

Before taking a 1958 Porsche on a longer drive, inspect all four tires and the spare for cracking, cuts, bulges, uneven wear, and proper pressure. Check that each tire matches the correct model-specific size, confirm the valve stems are sound, and pay special attention to any tube-type arrangement where leaks can develop slowly between drives. Wheel fasteners, brake condition, fluid levels, steering response, and lighting should also be part of the pre-trip routine on a car of this age.

Longer drives put sustained heat and load into a vintage tire, so small issues that go unnoticed on short local trips can become much more important on the road. A careful once-over also helps you catch age-related problems before they strand the car or force roadside improvisation. On a collector Porsche, confidence comes from preparation rather than assuming the last short drive proved everything is still ready.