1973 Subaru Tire Fitment Guide

1973 Subaru vehicles use three sizes across the DL and GL model range: 155R13, 6.15-13, and 145R13. The DL uses 155R13 and 6.15-13, while the GL uses those same two sizes plus 145R13. All three fitments mount on 13-inch wheels, and the radial products with published wheel guidance fit rim widths from 4.00 to 5.50 inches for 155R13 and 4.00 to 5.00 inches for 145R13.

That means year and make alone are not quite enough to choose a tire for every 1973 Subaru. If you own a GL, you need to confirm whether your car is meant to use the narrower 145R13 or one of the shared sizes. If you own a DL, the choice stays between the shared radial and bias-ply fitments, so the decision becomes more about construction and how you want the car to feel on the road.

On a 1973 Subaru, 6.15-13 is a numeric bias-ply size. The 6.15 refers to the tire's nominal section width, and the 13 refers to the wheel diameter in inches. Unlike a modern metric radial code, it does not use an R to indicate radial construction, so this format points to a traditional bias-ply tire style used on many small imported cars of the period.

That size matters because it gives a 1973 Subaru a more era-correct appearance and driving character than a radial replacement. Owners restoring a DL or GL to look and feel closer to its early-1970s presentation often prefer the numeric bias-ply route. Owners who expect more familiar tracking and ride behavior during regular use often move toward the radial alternatives, provided the model and wheel setup match.

On a 1973 Subaru, 155R13 is a metric radial size with a nominal section width of 155 millimeters and a 13-inch rim diameter. The R identifies radial construction. When no aspect ratio is shown in this older metric style, it is conventionally treated as an 80-series profile, which is why many reproduction and vintage radial products describe it that way.

That makes 155R13 the easiest modern format for many owners to understand because it bridges vintage fitment and later radial design. On a 1973 Subaru DL or GL, it is the shared radial size, so it often becomes the default choice for owners who want a 13-inch tire with period-appropriate proportions but a more familiar radial construction than the original-style numeric bias-ply alternative.

No. The 1973 Subaru DL and GL overlap, but they are not identical in tire fitment. Both models use 155R13 and 6.15-13, while the GL also uses 145R13. That extra GL fitment means the full 1973 Subaru range cannot be treated as a single one-size application, even though all of the tires involved still mount on 13-inch wheels.

The practical takeaway is simple: identify the model before you choose the tire. A DL owner can focus on the two shared sizes, while a GL owner may need to decide whether the car belongs with the narrower 145R13 radial or one of the shared fitments. That extra step helps avoid choosing a tire that is correct for the year and make but wrong for the specific model.

For a 1973 Subaru, the difference between 6.15-13 and 155R13 is mainly construction and the kind of driving experience you want. The 6.15-13 is a bias-ply fitment associated with more original early-1970s character, while the 155R13 is a radial used on both DL and GL models. Both mount on 13-inch wheels, so the decision is often less about wheel diameter and more about how authentic or road-oriented you want the car to be.

Owners restoring a Subaru for period presentation usually lean toward the bias-ply size because it better matches the tire technology of the era. Owners who plan to drive the car more regularly often prefer the radial route for its more familiar on-road manners. The smart move is to start with your model, then decide whether originality or everyday usability is the higher priority for your particular car.

1973 Subaru tire options in the radial sizes 155R13 and 145R13 are available in blackwall form. That appearance suits the understated, economy-car character Subaru carried in the U.S. market during the early 1970s. The blackwall look is also visually appropriate for owners who want their DL or GL to retain the simple, functional style these compact cars were known for.

Sidewall style can matter almost as much as size on a small vintage import because the tire is a large part of the car's visual stance. If your goal is restoration accuracy, a subdued sidewall generally looks more at home than a more decorative treatment associated with larger domestic cars of the same era. If your goal is regular driving, the appearance choice still matters, but construction and correct sizing should come first.

1973 Subaru radial fitments are available from Michelin, Dunlop, and Firestone, depending on size. In 155R13, Michelin and Dunlop are available. In 145R13, Michelin and Firestone are available. Those brands cover the radial side of the 1973 Subaru range and give owners more than one path when selecting a tire for a DL or GL.

Brand choice matters most after you have narrowed the car to the correct size and construction. Once that is settled, owners can compare details such as speed rating, wheel-width range, and casing weight where those figures are published. For a compact 1973 Subaru, the right brand decision is usually the one that best aligns with your preferred balance of appearance, period flavor, and how the car will actually be used.

For 1973 Subaru fitments with published wheel guidance, 155R13 radial tires fit 4.00- to 5.50-inch rims, and 145R13 radial tires fit 4.00- to 5.00-inch rims. All of those tires mount on 13-inch wheels. The shared wheel diameter is straightforward, but the wheel width still needs to match the tire's approved range so the casing sits correctly and the tread works as intended.

That is especially important on a light early Subaru because small changes in width can affect how the tire looks and behaves. Before committing to a size, measure the actual wheel rather than relying on assumptions about what may have been installed over the years. If your car has replacement wheels, that check becomes even more important, since the tire may be right for the model but not ideal for the wheel now on the car.

Tube status for 1973 Subaru radial tires can vary by product. The Michelin 155R13 and Michelin 145R13 carry TL tubeless markings, while the Dunlop 155R13 and Firestone 145R13 do not use the same explicit marking in the size line. That means you should not assume every tire in a given size shares exactly the same tube guidance just because the size itself is the same.

The safest approach is to match the tire's actual sidewall marking to the condition and design of your wheel. If your Subaru still uses original wheels, pay close attention to bead-seat condition and valve-stem setup before deciding whether to run a tire tubeless. If you are working with older restored wheels or have any uncertainty, that is the point where a tire professional or Subaru specialist can help confirm the best installation method.

All three 1973 Subaru sizes discussed here use a 13-inch rim diameter, so the wheel diameter itself is common across the range. That means original 13-inch Subaru wheels are often part of the solution whether you are considering 6.15-13, 155R13, or 145R13. The remaining question is wheel width, since the radial sizes have specific approved width ranges that should be respected.

In practical terms, original wheels can often stay with the car when moving between these fitments, but they still need to be checked as individual parts. A wheel that is correct in diameter but outside the suitable width range can compromise how the tire seats and wears. On a 1973 Subaru GL, that matters even more because the model spans the broadest fitment spread and may have changed hands or wheels several times over the decades.

A stored 1973 Subaru should be kept away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can accelerate sidewall cracking. Clean, dry concrete is fine if moisture is controlled, but long-term storage benefits from a cool indoor environment and occasional movement so the tires do not sit in one loaded position for months at a time. Bias-ply tires can flat-spot more readily during static storage than radials.

That matters on a small vintage Subaru because light cars can still develop noticeable vibration when old tires harden or take a set. If the car will sit for an extended period, maintaining proper inflation and rolling it periodically can help preserve the tire shape. Some owners also use stands to reduce load, but the key is to avoid conditions that age the rubber faster than the odometer ever will.

On a 1973 Subaru, tire life is usually governed more by age than mileage. Collector-car tires should be evaluated closely once they reach the five- to seven-year range, and many owners begin serious replacement consideration around ten years regardless of remaining tread. The DOT date code on the tire sidewall is the starting point for that discussion, since an older-looking car often accumulates far fewer miles than a modern daily driver.

Low annual use can create a false sense of security, especially on compact classics that still appear light and easy to drive. Rubber hardens, internal materials age, and storage conditions matter. A tire with excellent tread depth can still be due for replacement if the casing is old. On a 1973 Subaru that sees occasional weekend miles, age-based inspection is far more useful than waiting for a treadwear problem to appear.

Tires on a 1973 Subaru should be checked before every drive and inspected more thoroughly before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, and signs that the tire is losing pressure between drives. If your Subaru uses a tube-type setup, the valve stem and tube condition deserve the same attention because an old stem can become the weak link even when the tread still looks serviceable.

Frequent inspection is especially important on an older compact car because the tire is only one part of an aging system that includes brakes, suspension, and steering. A quick walkaround catches many problems early and helps separate harmless cosmetic aging from issues that can spoil a drive. The spare should also be included in that routine, since a decades-old spare can be unusable exactly when you need it most.

A 1973 Subaru DL used 6.15-13 and 155R13 fitments within its year-and-model range. In period terms, bias-ply construction remained common on economy cars, while radial adoption was growing, especially on imports and globally influenced compact cars. That makes the presence of both a numeric bias-ply size and a metric radial size entirely believable for an early-1970s Subaru, even though market-specific delivery and owner replacement history can blur what an individual car wore when new.

For restoration work, the safest path is to begin with the model and then compare the car against original manuals, dealer literature, or Subaru marque-club resources. Those sources can help sort out market and trim nuances that matter in judged settings. If your goal is authentic presentation, construction type, size format, and sidewall appearance usually matter more than simply choosing any tire that fits a 13-inch wheel.

Correct tire fitment absolutely matters when a 1973 Subaru is judged for authenticity. Size, construction, and sidewall presentation all shape whether the car looks right for its period. On an early Japanese compact, an incorrect modern-looking fitment can stand out quickly because the cars were small, the wheels were modest, and the tire profile is a major part of the car's visual proportion.

In practical terms, a judge or knowledgeable Subaru enthusiast is more likely to notice a mismatch in tire type than on a larger car where the wheel opening hides more detail. A radial may be fine for a driving event, but a bias-ply-style fitment can better support a period-focused restoration. For event-specific standards, Subaru clubs and marque specialists are still the best authority because judging expectations can vary from one show to another.

For a 1973 Subaru in 145R13, Michelin XAS-FF and Firestone F560 Radial are both blackwall radials, but they are not identical in published specs. The Michelin carries a 145HR13 74H TL marking and weighs 18 pounds. The Firestone F560 shows an 825-pound maximum load at 44 psi, fits 4.00- to 5.00-inch rims, and weighs 12.7 pounds. Both are 13-inch radial choices for the GL-specific narrow fitment.

That comparison is useful because it shows how two tires in the same nominal size can still differ in technical character. One may publish a fuller wheel-fitment and load picture, while the other emphasizes period European-style sizing and speed notation. On a 1973 Subaru GL, that means you should compare more than just the number on the sidewall and decide which tire best suits the car's intended role and the wheel it will actually use.

1973 Subaru radial options in 145R13 and 155R13 include H-rated examples, which carry a 130 mph speed ceiling. That is far above normal U.S. highway speeds and well beyond what an early-1970s Subaru compact would typically be asked to sustain. The real-world limit on a car of this age is usually the condition of the tires, wheels, brakes, steering, and suspension rather than the headline speed letter on the sidewall alone.

For highway use, construction choice still matters. A sound radial is often the easier path for regular road driving, while a bias-ply setup may better suit owners focused on historical feel and appearance. Either way, safety depends on fresh rubber, correct inflation, proper wheel condition, and a mechanically healthy car. Highway capability on paper is never a substitute for verifying that the entire 1973 Subaru is ready for sustained driving.

Inflation pressure on a 1973 Subaru should start with the factory recommendation for the specific model and size, then be checked against the tire maker's sidewall information for the exact product you are using. The available 145R13 Firestone radial publishes a maximum load of 825 pounds at 44 psi. The available 155R13 Dunlop radial publishes a maximum load of 937 pounds, but that load figure should not be treated as a blanket pressure recommendation for every 155R13 tire.

That distinction is important because maximum sidewall pressure and factory operating pressure are not the same thing. A reproduction or specialty radial may be engineered differently from the tire originally used on the car, so matching the model, size, and product matters. If you are comparing radial and bias-ply fitments on a 1973 Subaru, use the owner's manual and the individual tire's published guidance together rather than carrying one pressure assumption from one size to another.

Before a longer drive in a 1973 Subaru, inspect every tire for cracking, cuts, bulges, uneven wear, and proper inflation, and make sure the spare is usable. If your tire setup uses tubes, check the valve stems carefully and watch for slow pressure loss before the trip rather than during it. A longer outing is also the right time to look over wheel condition, lug security, and overall tread health, not just the visible outer sidewall.

The tire check should be part of a larger pre-trip review that suits a fifty-year-old compact car. Brake feel, steering play, wheel-bearing condition, fluid levels, belts, and charging performance all matter on a vintage Subaru that may spend much of its life in intermittent use. Tires are the car's direct connection to the road, but they are only as trustworthy as the rest of the vehicle supporting them.