1955 Porsche Tire Fitment Guide

1955 Porsche vehicles use three sizes overall, but they are split by model. The 1955 Porsche 356 uses 500-16 on a 16-inch rim, while the 1955 Porsche 356 A uses either 155R15 radial or 560-15 bias-ply on a 15-inch rim. Rim-width guidance appears within the available products: 500-16 is listed for 4.00 to 5.00-inch rims, 155R15 appears on 4.00 to 5.50-inch rims where stated, and 560-15 ranges from 4.5 inches to 4.50 to 5.50 inches depending on the tire.

That means year and make alone are not enough here. The first step is confirming whether your car is an early 356 or a 356 A, because the wheel diameter changes from 16 inches to 15 inches between those model lines. Once you have the model right, the 356 A choice becomes a matter of selecting either a radial or a bias-ply approach within the correct 15-inch fitment family.

On a 1955 Porsche, 500-16 is a numeric bias-ply size. The 5.00 figure is the nominal section width in inches, and the 16 is the wheel diameter in inches. In this application it belongs to the 1955 Porsche 356 and not the 356 A, and the available product uses bias-ply construction on a 16-inch rim.

A modern buyer should read 500-16 as an older American-style sizing format rather than a metric radial code. It points you toward an early-356 fitment and away from the 15-inch tires used on the 356 A. Before ordering, compare the tire size stamped on the car now, confirm the wheel diameter directly, and make sure the wheel falls within the listed rim-width range for the specific product.

On a 1955 Porsche, 155R15 is a Euro-metric radial size used on the 356 A. The 155 is the nominal section width in millimeters, the R identifies radial construction, and the 15 is the wheel diameter in inches. Because no separate aspect ratio is shown, this format is conventionally treated as an 80-series radial in period-style sizing.

That makes 155R15 very different in character from a numeric bias-ply code like 560-15, even though both fit 15-inch 356 A wheels. It is the size to investigate if your car already wears metric radials or if you want to stay within the proper 15-inch application while using a radial construction. Check the exact sidewall marking as well, since tube type and speed rating can differ among 155R15-based products.

No, 1955 Porsche models do not all use the same tire size. The 1955 Porsche 356 uses 500-16 on a 16-inch wheel, while the 1955 Porsche 356 A uses 15-inch sizes: 560-15 in bias-ply form and 155R15 in radial form. The difference is not just branding or sidewall style; it starts with wheel diameter and then extends to construction choice on the 356 A.

That split matters because a buyer cannot safely choose a tire for a 1955 Porsche by year and make alone. If your car is a 356 A, you still have to decide whether you want the traditional feel of a bias-ply tire or the road manners associated with a radial in the proper size family. If your car is an earlier 356, the 16-inch fitment narrows the selection immediately.

For a 1955 Porsche 356 A, the decision between 155R15 and 560-15 is mainly a construction and presentation choice within the correct 15-inch fitment family. The 155R15 options are radial blackwalls from Firestone and Michelin, while the 560-15 options are bias-ply tires from Firestone and US Royal offered in narrow whitewall and wide whitewall styles. The 356 does not use either of these sizes, so this comparison applies only to the 356 A.

A 356 A owner aiming for a more traditional mid-1950s appearance will usually start with 560-15, especially if sidewall styling is part of the restoration plan. A driver who wants a radial in the proper 15-inch format will focus on 155R15 instead. The smartest way to decide is to settle the car’s mission first: preservation-style presentation, or more frequent road use with a radial construction.

1955 Porsche tire choices include both blackwall and whitewall options, depending on size. The 500-16 fitment for the 356 is available as a blackwall bias-ply tire, and the 155R15 fitment for the 356 A appears as blackwall radial products. The 560-15 size for the 356 A adds narrow whitewall and wide whitewall versions in bias-ply form.

That variety matters most on the 356 A, because the same model can be fitted with either a plain blackwall radial look or a more visibly period-styled whitewall bias-ply look. Porsche buyers pursuing a factory-sporting appearance often lean toward blackwalls, while a whitewall choice changes the visual tone of the car more noticeably. If show presentation matters, align the sidewall style with the car’s intended market look and the standards of the event you care about.

Four brands appear across the available 1955 Porsche tire sizes: Firestone, Michelin, and US Royal, with each brand tied to specific fitments. Firestone covers all three sizes, including 500-16, 155R15, and 560-15. Michelin appears in 155R15 radial form for the 356 A, while US Royal appears in 560-15 bias-ply form for the 356 A.

Brand choice here follows size and construction more than simple preference. If you own a 356, the available path stays within the 500-16 Firestone application. If you own a 356 A, radial shoppers will compare Firestone and Michelin in 155R15, while bias-ply shoppers will compare Firestone and US Royal in 560-15, paying attention to sidewall style and any rim-width differences attached to the specific tire.

1955 Porsche rim-width guidance varies by size. The 500-16 fitment used on the 356 is listed for 4.00 to 5.00-inch rims. The 155R15 radial fitment used on the 356 A appears on 4.00 to 5.50-inch rims where specified, and the 560-15 bias-ply fitment for the 356 A is shown on either a 4.5-inch rim or a 4.50 to 5.50-inch range depending on the product.

That makes wheel verification worthwhile even after you have the correct size family. Some 356 A tires allow a broader rim-width range than others, so the specific product matters, not just the size printed on the sidewall. Measure the wheel if there is any doubt, especially on cars that may have had wheels changed over the years or that now wear a different construction than they did earlier in their restoration life.

Inner-tube fitment for 1955 Porsche tires depends on the size and the specific product. The 155R15 radial offerings for the 356 A vary by product: Michelin X is marked TL, Michelin XAS is marked TT, and Michelin XAS-FF is marked TL. The 500-16 and 560-15 products are bias-ply offerings without conflicting tube markings shown in the listed size field.

That means tube choice should never be assumed just from seeing a 15-inch Porsche tire. On a 356 A running 155R15, check the exact sidewall marking of the tire you plan to use and make sure it matches the wheel condition and intended setup. If your car still has original-style wheels, it is wise to review the wheel’s sealing condition and consult a Porsche specialist before mixing tube-type and tubeless assumptions.

A 1955 Porsche 356 A uses two listed tire sizes, 155R15 and 560-15, and both share the same 15-inch wheel diameter. That means the original 15-inch wheels are in the correct diameter family for either size. Rim-width compatibility still depends on the actual wheel and the specific tire, because the listed products show fitment ranges centered around roughly 4.00 to 5.50 inches depending on size and brand.

In practical terms, wheel diameter is the easy part of the decision and wheel width is the part that deserves checking. A car that has stayed original for decades, or one that has had wheels swapped during restoration, may not match assumptions made from model name alone. Confirm the wheel width before finalizing a 356 A tire choice, especially if you are moving from a bias-ply setup to a radial one or vice versa.

A 1955 Porsche should be stored out of direct sunlight and away from electric motors, battery chargers, welders, and other ozone-producing equipment that can accelerate sidewall aging. Keep the floor area dry, maintain proper inflation, and move the car periodically so the tires are not held in one loaded position for months at a time. Bias-ply tires are generally more prone to flat-spotting during long static storage than radials.

That advice matters for both the early 356 and the 356 A because collector cars often sit longer than modern daily drivers. If the car will be parked for an extended season, rolling it occasionally or using stands to reduce prolonged loading can help preserve shape and ride quality. A breathable cover is fine, but storing the car in a damp, sunlit, or ozone-heavy space will age the tires faster than mileage ever will.

Tires on a 1955 Porsche should be judged more by age and condition than by miles traveled. A useful collector-car rule is to begin evaluating them closely once they are around five to seven years old and to treat roughly ten years as the point where replacement deserves serious consideration, even if tread depth still looks good. The DOT date code on the tire helps establish actual age.

That timeline is especially important on a lightly used Porsche, because the tire can age out long before it wears out. Sidewall cracking, hardening, loss of flexibility, and repeated air loss all matter more than odometer readings in this kind of ownership. If the car has older tires fitted during a restoration that was completed years ago, review their age now rather than assuming low mileage means they are still suitable.

Tires on a 1955 Porsche should be inspected before every drive and again before any longer outing. Check for visible cracking, cuts, bulges, tread separation signs, uneven wear, and proper inflation, and make sure the car is holding pressure consistently from one drive to the next. If your setup uses tube-type tires, the valve stems and tube-related air retention deserve just as much attention as the casing itself.

A brief inspection catches most age-related problems before they become roadside problems. On a small, light sports car like a 356 or 356 A, the steering feel is usually sensitive enough that a tire issue may show up quickly, but it is better to spot it in the garage than on the road. Include the spare in the same routine, since a decades-old spare often gets forgotten until it is suddenly needed.

A 1955 Porsche 356 would have been delivered in an era when bias-ply construction was still the normal original-equipment standard, and the listed size for the model is 500-16. That aligns with the earlier 356’s 16-inch fitment and period construction expectations. No original-equipment brand should be assumed from the available replacement choices alone, because period supply could vary by market and delivery context.

For a restoration, the important point is that an early 356 is best researched as a 16-inch bias-ply application first, not as a 15-inch 356 A setup. If you are preparing a high-level car for marque judging, confirm market-specific details through Porsche registries, archives, or model experts. The car’s delivery market, wheel type, and judging standard can all shape what counts as the most authentic presentation.

Correct tire fitment absolutely matters when showing a 1955 Porsche, especially at marque-focused events. Judges and knowledgeable enthusiasts often notice whether the car has the right size family, the correct construction type for the restoration goal, and an appropriate sidewall style for the era. A 500-16 early 356 presented on the wrong wheel diameter, or a 356 A wearing an obviously mismatched sidewall style for its intended presentation, can stand out quickly.

What counts as acceptable depends on the event. A preservation or concours-oriented standard may look closely at bias-ply versus radial construction and whether a whitewall belongs on the specific car’s presentation, while a touring event may be more relaxed. Decide early whether your Porsche is being restored for points, for historical flavor, or for road use first, then choose the tire that supports that goal without confusing the car’s period identity.

For a 1955 Porsche 356 A in 155R15 form, Michelin XAS and Michelin XAS-FF share the same 155HR15 size, blackwall appearance, 15-inch rim diameter, and H speed rating with a 130 mph ceiling. Their listed setup difference is tube fitment: Michelin XAS is marked TT, while Michelin XAS-FF is marked TL. Both also show the same 4.00 to 5.50-inch rim-width range and the same listed weight.

That makes the choice less about dimensions and more about how the tire is intended to be used on the wheel you have. If your 356 A is being assembled with a tube-type arrangement, the XAS fits that path directly. If you are working with a tubeless-marked setup, the XAS-FF lines up with that approach, but it is still wise to verify the condition and suitability of the wheel itself before final fitment.

1955 Porsche tires can be suitable for highway use when the size, construction, condition, and speed rating all match the car and the intended driving. Among the 155R15 radial choices for the 356 A, Michelin X is T rated to 118 mph and Michelin XAS and XAS-FF are H rated to 130 mph. The listed bias-ply sizes do not show speed-letter markings here, so they should be approached with period-appropriate expectations and careful condition checks.

On a mid-1950s Porsche, the mechanical condition of the car often matters as much as the tire itself once speeds rise. Brakes, steering components, suspension, wheel condition, and alignment all shape how secure the car feels on the road. Treat the tire as one part of the system: a properly rated radial on a worn-out chassis will not solve broader roadworthiness issues, and an older bias-ply tire should never be used beyond its safe condition.

Inflation pressure on a 1955 Porsche should follow the vehicle guidance for the model and the tire maker’s rating for the exact tire you are using. The available tires show different load-and-pressure pairings by size: 500-16 is listed at 760 pounds at 32 psi, 560-15 is listed at 970 pounds at 32 psi, and one 155R15 radial is listed at 1045 pounds at 44 psi. Those figures are product ratings, not a blanket recommendation to run every size at the same pressure.

Use the original owner’s manual or a Porsche specialist’s guidance for target operating pressures, then make sure that number stays within the tire’s own rated capability. Pressure should not be transferred casually from a bias-ply 560-15 to a 155R15 radial, or from a 356 to a 356 A. Matching the pressure to both the tire and the car preserves handling balance and avoids chasing ride issues with the wrong baseline setting.

Before a longer drive in a 1955 Porsche, inspect every tire for cracking, cuts, bulges, uneven wear, and signs of age hardening, and verify cold pressures before departure. Make sure the valve stems are in good condition, and if your setup uses tube-type tires, pay extra attention to slow air loss and stem condition. The spare deserves the same age and pressure check as the four tires on the car.

A longer outing in a 356 or 356 A also calls for a broader vintage-car check beyond the tires. Wheel fasteners, brake function, steering play, fluid levels, charging health, and basic lighting are all worth reviewing before you add distance and heat to the equation. If the car has been sitting, a short local test drive after inflation and inspection is a better first step than heading straight onto a long highway route.