1971 Subaru Tire Fitment Guide

1971 Subaru vehicles in this fitment group use two tire sizes, and both belong to the 1971 Subaru FF-1: 155R13 and 6.15-13. Both sizes mount on 13-inch wheels. The 155R13 radial has a confirmed rim width range of 4.00 to 5.50 inches across the products available in that size, while the bias-ply 6.15-13 remains the period-style alternative for the same model family.

That means a 1971 Subaru buyer does not need to sort between multiple models first, but does need to decide whether the car is staying closer to its original bias-ply character or moving to a radial setup. Checking the wheel's actual width before ordering is especially important if the car has been restored, modified, or fitted with replacement wheels at any point in its life.

On a 1971 Subaru, 155R13 is a euro-metric radial size. The 155 refers to a nominal section width of 155 millimeters, the R indicates radial construction, and the 13 is the wheel diameter in inches. When no aspect ratio is stated in this older metric style, it is conventionally treated as an 80-series profile.

For an FF-1 owner, that size points toward a later-style replacement philosophy rather than the older numeric bias-ply system. It keeps the car in the same 13-inch wheel family while giving you a tire format that is more familiar to modern drivers. The next check is matching the tire to the actual rim width and confirming whether you want a strictly period appearance or a more updated driving feel.

On a 1971 Subaru, 6.15-13 is a numeric bias-ply size. The 6.15 identifies the nominal section width in inches, and the 13 identifies the wheel diameter in inches. Unlike a radial metric code, this older format does not use an R to indicate construction, so the bias-ply structure is understood from the size type and the construction designation itself.

That makes 6.15-13 the more traditional choice for an FF-1 owner focused on a period-correct presentation. It speaks the tire language common to compact cars from the era just before radial sizing became fully dominant. If your goal is authenticity in stance and appearance, this is the size family to research first before comparing individual tire options.

For a 1971 Subaru FF-1, the choice between 6.15-13 and 155R13 is primarily a choice between bias-ply and radial construction. The 6.15-13 stays closest to the period style the car would have known in its era, while 155R13 moves into a radial format with blackwall products from Michelin and Dunlop. Both remain within the same 13-inch wheel diameter family.

Owners restoring an FF-1 for show presentation often begin with the bias-ply path because construction type is part of the car's visual and historical character. Owners who plan to use the car more regularly on modern roads often lean toward the radial route for a more contemporary driving feel. The best first step is deciding what role the car serves in your collection, then verifying the wheel width before making the final selection.

The current 155R13 options for 1971 Subaru vehicles are available as blackwall radials. That sidewall treatment suits the FF-1's small imported-car character and keeps the appearance understated rather than decorative. No alternate sidewall treatment appears within the current radial choices for this year and make.

For many early Subaru owners, that is appropriate anyway, since the brand's economy-car image in this period did not depend on wide whitewalls or flashy sidewall styling. If you are balancing originality and usability, sidewall appearance may be a simpler decision than construction type. Choose the look that matches the way your FF-1 is being restored, then move on to confirming the exact size and wheel fit.

Michelin and Dunlop both offer 155R13 tires for 1971 Subaru vehicles. Michelin's offering is the XAS-FF in 155HR13 form, while Dunlop offers the SP Sport Aquajet in the same basic size family. Both are blackwall radials aimed at owners keeping the FF-1 in a compact, era-appropriate radial format.

Those two brands give an FF-1 owner a choice within the same radial size without changing wheel diameter. Michelin and Dunlop each have strong historical associations with imported-car fitments from the period, which can matter to enthusiasts who want the right look as much as the right dimensions. After choosing the size family, compare the individual tire's construction markings, speed rating, and wheel-width suitability.

For 1971 Subaru vehicles using 155R13, the supported rim width range runs from 4.00 to 5.50 inches on a 13-inch wheel. That range is broad enough to cover many original small-car wheel applications, but it still needs to be checked against the actual wheel on the car. Both the radial and bias-ply size families share a 13-inch rim diameter.

That shared diameter often makes the tire decision look simpler than it really is. Diameter alone is not enough; wheel width, wheel condition, and whether the car is still wearing its factory-style rims all affect the final fit. On an older FF-1, especially one that has passed through several owners, measuring the wheel before choosing a tire is time well spent.

Tube use on 1971 Subaru tires depends on the specific size and product. The Michelin 155HR13 is explicitly marked TL, meaning tubeless, while the Dunlop 155R13 does not use the same tube marking in its size description. That means tube status can vary by product language and should be confirmed on the exact tire you select.

The wheel matters just as much as the tire here, because an older rim may influence whether a tube-type setup is appropriate even when a tire is built as tubeless. If your FF-1 still has original wheels, inspect the wheel condition and valve stem area carefully before final assembly. A restorer familiar with early imported steel wheels can help determine the most appropriate setup.

A 1971 Subaru FF-1 uses both 155R13 and 6.15-13 within the same 13-inch wheel diameter family, so original wheels can often remain part of either path. The key point is confirming more than diameter alone, since radial and bias-ply tires can have different wheel-width preferences. The 155R13 radial products fit 4.00- to 5.50-inch-wide rims.

That makes the original wheel a strong starting point, but not a final answer until it is measured and inspected. If the car still has factory-style wheels, verify width, bead-seat condition, and overall trueness before fitting new tires. Keeping the original wheels is often desirable on a collector Subaru, but wheel condition should guide the decision as much as originality.

A 1971 Subaru should be stored in a cool, dry space away from direct sunlight, electric motors, welders, battery chargers, and other ozone-producing equipment that can age rubber prematurely. Keep the tires clean, maintain proper inflation, and move the car periodically so one section of the tread is not carrying the load for months at a time. Bias-ply tires tend to flat-spot more readily during long static storage than radials.

That matters on an FF-1 because the car is light, compact, and often used only seasonally. If the car will sit for extended periods, some owners prefer to roll it occasionally or support it in a way that reduces prolonged tire loading. Storage habits are one of the easiest ways to preserve appearance, maintain smoother road manners, and extend the useful life of collector-car tires.

Tires on a 1971 Subaru should be judged more by age and condition than by mileage, because collector cars often accumulate miles slowly. A good rule is to evaluate them closely after about five to seven years of service and to treat the ten-year mark as a serious replacement point regardless of remaining tread. The DOT date code on the tire sidewall tells you when the tire was made.

An FF-1 that comes out only for occasional drives can still age its tires even if the tread looks fresh. Rubber hardens over time, sidewalls can crack, and long storage cycles can change how the tire behaves. Many owners focus on mileage and miss the calendar, but age is usually the more important factor on a vintage Subaru that spends much of its life parked.

Tires on a 1971 Subaru deserve a quick inspection before every drive and a more thorough inspection before any longer outing. Look for sidewall cracking, cuts, uneven wear, bulges, embedded debris, and any sign that the tire is not holding pressure properly. If your setup involves a tube-type arrangement, inspect valve stems and related hardware just as carefully as the tire itself.

That routine is especially important on a low-use FF-1 because problems can develop quietly while the car sits. A tire can look acceptable from a few feet away and still have age-related issues that only show up during close inspection. Building a pre-drive walkaround into your routine helps catch small problems before they interrupt a road trip or create avoidable risk.

A 1971 Subaru FF-1 sits in the period when compact imported cars could still be found with traditional bias-ply sizing even as radial fitments were becoming increasingly common. The two size families associated with the FF-1 are 6.15-13 in bias-ply form and 155R13 in radial form, both on 13-inch wheels. For strict factory-delivery accuracy, buyers often verify market-specific details with Subaru marque specialists and period literature.

That is important because early imported cars sometimes varied by market, trim approach, and running production changes. If your FF-1 is being restored for judging, construction type can matter just as much as the nominal size. Starting with the correct size family for the car's intended presentation will make the rest of the restoration decisions easier and more coherent.

Correct tire fitment absolutely matters when a 1971 Subaru is judged for originality. On a show field, judges and knowledgeable enthusiasts often notice whether the car wears the proper size family, the expected construction type for its period presentation, and a sidewall style that suits the era. A radial tire on a car judged to strict factory standards can stand out just as clearly as an incorrect decorative sidewall.

For an FF-1, the biggest authenticity question is usually whether the car should remain in a bias-ply presentation or whether a radial conversion is acceptable for the event and class. Different clubs and judging standards handle that question differently. Before finalizing the car, check the event rules or consult a Subaru marque club so your tire choice matches the level of originality being expected.

A 1971 Subaru owner usually chooses bias-ply tires to preserve the period-correct visual and historical character of an early FF-1. The 6.15-13 size speaks the original tire language of the era in a way that a later-style radial code does not. For restoration-minded enthusiasts, that matters because construction type affects not only how the car drives, but how authentically it presents.

That does not automatically make bias-ply the right answer for every FF-1. It simply means the tire choice should follow the car's mission. If the Subaru is being restored for shows, historical consistency may lead the decision; if it will be driven more regularly, the owner may prioritize a radial size within the same wheel diameter family while accepting that the appearance and feel move away from a pure period setup.

1971 Subaru tires can be suitable for highway use when they are in good condition, properly fitted, and used within their construction and speed-rating limits. The 155R13 radial options carry H ratings, which correspond to a 130 mph ceiling. In real-world use, the mechanical character of an early-1970s Subaru often becomes the practical limit long before the tire's published speed capability does.

The more important issue for an FF-1 is overall age, inflation, and vehicle condition rather than chasing a high speed number. A vintage compact car with older brakes, suspension parts, or worn steering components should be driven with that whole system in mind. A fresh, correctly fitted tire helps, but it should be treated as one part of a broader roadworthiness picture.

Inflation pressure on a 1971 Subaru should follow the vehicle manufacturer's recommendation for the car and the tire manufacturer's guidance for the exact reproduction or radial tire being used. The available load information in 155R13 includes a Dunlop rating of 937 pounds, but that should not be treated as a universal pressure target for every tire in the FF-1 size family. Pressure and load are tied to the specific tire design.

That is why it is important not to transfer one figure from one brand or one size to another. Start with the Subaru owner's literature if you have it, then confirm the tire maker's specifications for the exact product on the car. Once the baseline is set, monitor wear and handling so you can catch underinflation or overinflation before it affects safety or tire life.

Before a longer drive in a 1971 Subaru, inspect each tire for cracking, cuts, bulges, uneven wear, embedded objects, and proper inflation. Check valve stems closely, and if the car uses a tube-type setup, pay extra attention to slow pressure loss and hardware condition around the stem area. Do not forget the spare, since a decades-old spare is often the weakest tire on the car.

An FF-1 also deserves the broader once-over that any vintage car needs before distance driving: brakes, steering, wheel bearings, lights, fluids, and charging system condition all matter. The tire check is simply the part most likely to be overlooked because the car may have seen very little mileage. A careful pre-trip inspection helps turn a collector-car outing into a drive you can enjoy rather than troubleshoot.