The 1979 Subaru GL came from the era when compact imports were winning buyers with sensible dimensions, light weight, and everyday practicality rather than excess. On a car like this, tire choice has an outsized effect on stance, steering feel, and the overall period character of the drive. The 1979 Subaru GL uses two primary 13-inch fitments: a 155R13 radial and a 6.15-13 bias-ply. That gives owners a meaningful choice between a more traditional bias-ply presentation and a radial setup available from Michelin and Dunlop in blackwall form. The right decision starts with how the car is equipped now and whether the goal is restoration-minded appearance, familiar road manners, or both.
Which Tire Size Is Right for The 1979 Subaru GL
The 1979 Subaru GL uses two primary tire sizes, and the difference is construction rather than wheel diameter, since both fit 13-inch rims. The first step is confirming whether your car is set up for the 155R13 radial or the 6.15-13 bias-ply, then choosing the tire style and overall presentation that best match your restoration goals and driving plans.
A 155R13 uses a metric section width of 155 millimeters, radial construction, and a 13-inch rim diameter. On the 1979 Subaru GL, this is the radial-format fitment and suits owners who want a tire sized in the conventional import radial style of the period. Available choices include Michelin and Dunlop products in blackwall form, with series such as Michelin XAS-FF and SP Sport Aquajet adding some character differences within the same fitment. It is the size to evaluate when the car already has a radial setup or when preserving a period import look matters.
A 6.15-13 is a numeric bias-ply size, with the 6.15 indicating nominal section width in inches and the 13 identifying rim diameter. On the 1979 Subaru GL, this size represents the traditional bias-ply fitment and appeals to owners seeking an earlier tire construction and a more vintage overall presentation. Bias-ply selection is less about modern metric sizing and more about maintaining the character of the original wheel-and-tire format used on many small cars of the era. It deserves a careful look when appearance, restoration style, and existing wheel setup are the priorities.
Sub-model fitment is straightforward here because the covered GL Coupe uses the same two 13-inch tire sizes already associated with the 1979 Subaru GL. Checking the exact sub-model still matters so the tire choice stays aligned with the car’s present wheel setup and the construction you want to keep.
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1979 Subaru GL Coupe
The 1979 Subaru GL Coupe uses the same fitment pattern as the core model, with both 155R13 radial and 6.15-13 bias-ply options on 13-inch rims. That means the real choice is less about sub-model differences and more about whether the coupe is being kept in a restoration-oriented bias-ply format or a period-style radial setup.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1979 Subaru GL Tires for Sale
Available 155R13 radial options for the 1979 Subaru GL include Michelin and Dunlop blackwall tires in distinct series such as Michelin XAS-FF and SP Sport Aquajet. The product grid is where to compare construction details, series character, and rim-width compatibility within this 13-inch fitment.
These 1979 Subaru GL tire FAQs focus on the two primary 13-inch sizes, the difference between radial and bias-ply fitment, available product choices, and the wheel, condition, and maintenance checks worth making before road use.
Tire Size & Fitment
What tire size fits a 1979 Subaru GL?
The 1979 Subaru GL uses two primary tire sizes: 155R13 in radial construction and 6.15-13 in bias-ply construction. Both sizes are built for 13-inch rims, so the main difference is the sizing system and tire construction rather than wheel diameter.
Choosing between them starts with the setup already on the car. A GL that has been running radial tires may be best evaluated around the 155R13 size, while a restoration-oriented car may stay with 6.15-13 bias-ply. The safest path is to confirm the actual wheel dimensions and compare clearance before changing construction.
What size rim does a 1979 Subaru GL use?
The 1979 Subaru GL uses a 13-inch rim diameter with both of its primary tire sizes. That applies to the 155R13 radial fitment and the 6.15-13 bias-ply fitment, so rim diameter remains consistent even though the tire construction can differ.
Rim diameter alone does not settle the whole fitment question. Wheel width, the car’s current setup, and the construction you plan to run should still be checked before selecting tires. That matters most when moving between bias-ply and radial tires, since the same 13-inch rim diameter does not automatically mean identical fitment behavior.
What does 6.15-13 mean on a 1979 Subaru GL?
A 6.15-13 is a numeric bias-ply size. The 6.15 refers to nominal section width in inches, and the 13 refers to the rim diameter in inches. On a 1979 Subaru GL, it identifies the traditional bias-ply fitment rather than a modern metric radial size.
That matters because a numeric bias-ply tire is selected differently from a metric radial such as 155R13. Owners usually choose it for a more vintage presentation and to stay closer to an earlier tire format. Before switching away from it, check wheel width, overall vehicle setup, and whether preserving a period-style appearance is part of the goal.
Bias-Ply & Radial Options
Is 6.15-13 a bias-ply or radial tire for the 1979 Subaru GL?
On the 1979 Subaru GL, 6.15-13 is a bias-ply tire size. It uses the older numeric sizing format and represents the traditional construction option for this car, while 155R13 is the radial-format fitment on the same 13-inch rim diameter.
That distinction affects both appearance and setup decisions. A bias-ply tire can suit a restoration-minded car, while a radial may be preferred when the vehicle is already configured around radial fitment. Before changing constructions, verify wheel width, inspect suspension and steering condition, and make sure there is adequate clearance through the full range of motion.
Should I use bias-ply or radial tires on a 1979 Subaru GL?
A 1979 Subaru GL can be equipped in either direction within its primary fitments, using 6.15-13 bias-ply or 155R13 radial tires. The better choice depends on what matters most for the car: maintaining a traditional period-style presentation or staying with a radial-format setup already in place.
The decision should match the actual wheels and the intended use of the car. Owners focused on preservation may lean toward the bias-ply format, while drivers keeping a radial-equipped GL may want to remain with 155R13. Either way, avoid assuming the constructions are interchangeable without checking wheel compatibility and vehicle clearance first.
What should I check before converting my 1979 Subaru GL from bias-ply to radial tires?
Start by confirming that the car’s wheels are appropriate for the radial size you plan to use, which in this case is the 155R13 format. The 1979 Subaru GL uses the same 13-inch rim diameter across both primary sizes, but construction changes still require more than a simple diameter match.
Look closely at wheel width, tire-to-fender clearance, steering clearance, and the condition of suspension and steering components. A collector car that has sat for long periods should also be checked for aged bushings, alignment issues, and uneven tire wear. Those details help determine whether the conversion makes sense for the car as it exists today.
Choosing the Right Tire
What should I consider when choosing a 155R13 tire for a 1979 Subaru GL?
Start with the basics: correct 155R13 sizing, radial construction, and 13-inch rim compatibility. From there, the real comparison points are brand, tire series, sidewall presentation, and wheel-width suitability, since the available GL products include blackwall radial options from Michelin and Dunlop.
A buyer comparing 155R13 tires should think about how the car will be used and how authentic the finished look needs to feel. Michelin XAS-FF and Dunlop SP Sport Aquajet each bring a distinct period character within the same size. Matching the tire to the wheel and to the car’s intended appearance usually matters more than chasing small specification differences.
What sidewall styles are available for 1979 Subaru GL tires?
Among the available 155R13 products for the 1979 Subaru GL, the sidewall style is blackwall. That gives the car a clean, understated import appearance and keeps the visual focus on the wheel and the tire’s overall profile rather than on stripes or raised lettering.
Sidewall choice matters because it changes the look of a small vintage car very quickly. A blackwall tire often suits a practical late-1970s compact presentation, but the right answer still depends on how the GL is being restored or preserved. Appearance should be weighed alongside correct size, construction, and wheel compatibility before making a final choice.
What brands offer tires for the 1979 Subaru GL?
The available 155R13 radial tire options for the 1979 Subaru GL include Michelin and Dunlop. Those brands appear in period-appropriate series such as Michelin XAS-FF and SP Sport Aquajet, giving buyers more than one approach within the same basic radial fitment.
Brand choice is most useful when it helps you narrow the car’s final character rather than simply filling the size. Some owners prefer a particular vintage look tied to a known series, while others focus on staying within the right dimensions and construction. Rim-width compatibility and the car’s intended use should still be part of the comparison.
Restoration & Appearance
Which tire should I choose for a period-style 1979 Subaru GL?
A period-style 1979 Subaru GL can point in two directions, depending on the look you want to preserve. The 6.15-13 bias-ply keeps the older numeric format and a more traditional presentation, while the 155R13 radial reflects the compact import radial style that also belongs naturally to this late-1970s car.
The best choice depends on how faithfully the car is being restored and what wheel setup is on it now. Owners aiming for exact historical detail should compare the car against marque references, original sales literature, or restoration documentation. For many drivers, the right answer is the tire that keeps the correct size family and visual balance.
How does tire construction affect the appearance of a restored 1979 Subaru GL?
Tire construction changes more than the technical makeup of the tire; it changes the visual language of the car. On a restored 1979 Subaru GL, a 6.15-13 bias-ply tends to support a more traditional vintage presentation, while a 155R13 radial gives the car a later import look consistent with metric radial sizing.
That visual difference is especially noticeable on a compact car with modest wheel openings and narrow tires. Construction choice should be considered alongside ride height, wheel design, and the overall restoration goal rather than as an isolated specification. Keeping the tire size and construction aligned with the car’s intended era impression usually produces the best result.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1979 Subaru GL?
Yes, modifications can affect tire fitment on a 1979 Subaru GL even when the tire size itself is correct. Changes to wheel width, wheel offset, suspension height, springs, or body clearance can alter how a 155R13 or 6.15-13 tire sits and moves within the wheel opening.
A car with aftermarket wheels or suspension work should be checked more carefully than a stock example. Turning clearance, fender clearance, and spacing around suspension parts deserve attention before regular road use. On a small car, even modest changes can matter, so the actual current setup should guide the final tire decision.
What should I inspect before driving a 1979 Subaru GL on new tires?
Before driving a 1979 Subaru GL on new tires, inspect the wheels for correct diameter and sound condition, then check that the tires are seated properly and inflated evenly. It also makes sense to look over the valve stems, lug hardware, and visible suspension and steering components before putting miles on the car.
A short test drive should be used to confirm that nothing rubs during turning or over bumps. After that, recheck air pressure and look for any signs of uneven contact or interference. Older collector cars often reveal alignment or component issues only after fresh tires are installed, so an early follow-up inspection is worthwhile.
How should tires on a collector 1979 Subaru GL be maintained?
Tires on a collector 1979 Subaru GL should be kept properly inflated, inspected regularly for cracking, cuts, bulges, and unusual tread wear, and protected from long periods of heat, sunlight, moisture, and ozone exposure. Low-mileage vintage cars often age their tires through time and storage as much as through road use.
Routine checks matter even when the car is rarely driven. A GL that spends most of its life parked should still have its tire condition reviewed before each outing and after longer storage periods. Catching slow air loss, sidewall aging, or developing flat spots early helps preserve both ride quality and confidence on the road.
