1978 Oldsmobile Starfire Tires

The 1978 Oldsmobile Starfire uses three primary tire sizes depending on sub-model: A78-13, B78-13, and BR70-13. A78-13 and B78-13 are bias-ply fitments, while BR70-13 is a radial fitment. All of them use a 13-inch rim, but they do not apply universally across every Starfire configuration.

The practical decision starts with identifying whether the car is an L-4, V6, or V8. An L-4 can use either A78-13 or B78-13, the V6 uses B78-13, and the V8 uses BR70-13. If the car has had wheel, suspension, or brake changes over the years, confirm the actual wheel setup before choosing a replacement tire.

The covered tire fitments for the 1978 Oldsmobile Starfire all use a 13-inch rim diameter. That applies whether the car is fitted with A78-13, B78-13, or BR70-13. Even though the tire sizes and constructions vary by sub-model, the wheel diameter stays consistent across these primary fitments.

Rim diameter is only one part of the fitment check, so it should not be the only measurement used before ordering tires. A car that still has its original-style 13-inch wheels may be straightforward, but an aftermarket wheel with a different width or profile can affect what works cleanly. Measuring the installed wheels is a smart step, especially on a collector car with an uncertain history.

No. The 1978 Oldsmobile Starfire does not use one tire size across every covered sub-model. The L-4 uses A78-13 or B78-13, the V6 uses B78-13, and the V8 uses BR70-13. That means tire choice depends on the exact version of the car, not just the year and model name.

This matters because the difference is not only size-related but also construction-related. A buyer looking at a V8 should be focused on the BR70-13 radial fitment, while an L-4 or V6 owner may be comparing period-style bias-ply tires with radial equivalents for bias-ply sizes. Confirming the sub-model first prevents choosing a tire that matches the rim diameter but not the intended fitment.

A78-13 is a bias-ply tire size for the 1978 Oldsmobile Starfire. It is one of the primary fitments used on the Starfire L-4 and belongs to the vintage alphanumeric bias-ply sizing system. It is not the same thing as a modern radial size, even though several radial equivalents are available for comparison.

That distinction matters because a buyer may be choosing between retaining the original-style construction or moving to a radial alternative. Keeping A78-13 bias-ply preserves the traditional size format and look, while a radial equivalent changes the construction and sizing convention. Before changing over, confirm the wheel width, the car's present setup, and any clearance concerns created by age, repairs, or modifications.

Radial equivalents for B78-13 include 175R13 as an 80-series metric radial, P175/75R13 as a 75-series P-metric radial, P185/70R13 as a 70-series P-metric radial, and 650R13 as a bias-look radial. These are alternative radial formats that relate to the B78-13 bias-ply size rather than additional primary Starfire fitments.

Each option should be viewed as a comparison point with its own sizing convention and profile. The recommended rim-width range tied to the B78-13 equivalency is 4-6 inches, which makes wheel measurement worthwhile before making a switch. Clearance at the fenders and suspension should also be checked, especially if the Starfire no longer has its original wheels or ride height.

That depends on the Starfire sub-model and on the goal for the car. A78-13 and B78-13 are primary bias-ply fitments on covered versions of the 1978 Oldsmobile Starfire, while BR70-13 is already a radial primary fitment on the V8. For the bias-ply sizes, radial equivalents exist and can be considered as alternatives rather than automatic substitutes.

Bias-ply construction usually makes the most sense when a traditional appearance is the priority, while a radial alternative may appeal to an owner planning more routine road use. The right choice also depends on wheel width, clearance, and the car's actual setup today. Matching the construction to the sub-model and intended use is more important than treating one construction as universally correct.

Start with the fact that B78-13 is a primary bias-ply size used on the 1978 Oldsmobile Starfire, including the V6 and one of the L-4 fitments. The main decision is whether the car needs a traditional bias-ply tire in that size or whether a radial equivalent is more appropriate for the way the car will be driven and presented.

Wheel dimensions and the current condition of the vehicle matter just as much as the sidewall number. A car kept close to period style may favor staying with B78-13 bias-ply, while a driver-oriented car may lead an owner to compare 175R13, P175/75R13, P185/70R13, or 650R13. Any conversion should be checked against wheel width and available clearance rather than assumed from size code alone.

The first step is not comparing tread or appearance but confirming which Starfire sub-model is being fitted. The L-4 uses A78-13 or B78-13, the V6 uses B78-13, and the V8 uses BR70-13. Once that is established, the tire decision becomes much clearer because the car's correct primary fitment narrows immediately.

After the sub-model is confirmed, think about construction and intended use. A bias-ply Starfire may stay with its original-style format for restoration character, or it may be evaluated against radial equivalents where available. A V8 using BR70-13 should stay focused on the radial fitment path. Also verify the wheels currently on the car, since decades of ownership can easily change what is mounted.

Rim width matters most when a 1978 Oldsmobile Starfire owner is considering radial equivalents for the bias-ply sizes. A78-13 carries a recommended radial-equivalent rim-width range of 4-5 inches, while B78-13 carries a recommended range of 4-6 inches. Those values are useful because they help frame which equivalent sizes are reasonable to evaluate on a 13-inch wheel.

A 13-inch diameter wheel can still vary enough in width to affect how a tire sits and how much clearance remains at the suspension or fender edges. Measuring the wheel on the car is smarter than relying on memory, especially with an older hatchback that may have seen replacement wheels over time. Width should be checked alongside the selected size rather than treated as a secondary detail.

For a period-style 1978 Oldsmobile Starfire, the starting point is the sub-model's original primary fitment path. That means A78-13 or B78-13 for the covered bias-ply applications and BR70-13 for the covered radial application. Staying within those primary size families usually keeps the car closer to the visual character associated with the way it was equipped in the late 1970s.

A restoration-minded owner should match the tire choice to the exact car before worrying about broader appearance trends. Bias-ply construction generally supports a more traditional presentation on the L-4 and V6, while the V8's BR70-13 radial fitment points in a different direction. If exact originality matters beyond size and construction, marque references and vehicle-specific historical documentation are worth consulting.

Tire construction changes more than road feel on a restored 1978 Oldsmobile Starfire; it also changes the visual character of the car. A78-13 and B78-13 are bias-ply fitments, which support a more traditional late-1970s look, while BR70-13 is a radial primary fitment on the V8. That makes construction part of the restoration conversation, not just a technical detail.

A Starfire being restored for period-style presentation should usually begin with the construction type tied to its sub-model. Owners considering a radial conversion on an A78-13 or B78-13 application should expect the tire's look to shift along with the sizing format. The best approach is to decide early whether the priority is visual authenticity, regular road use, or a balance between the two.

Yes. Modifications can change tire fitment on a 1978 Oldsmobile Starfire even when the replacement size seems correct on paper. Aftermarket wheels, altered wheel width, suspension changes, brake upgrades, or body repairs can all affect how an A78-13, B78-13, or BR70-13 tire sits in the wheel opening and clears nearby components.

That is especially important on a compact collector car, where small changes can have a noticeable effect on steering or fender clearance. A Starfire that has been lowered, fitted with different wheels, or rebuilt with non-stock parts should be measured before a tire is chosen. Confirm diameter, width, and clearance at full steering lock rather than assuming the current setup still matches original dimensions.

Before driving a 1978 Oldsmobile Starfire on new tires, inspect the wheels, valve stems, and overall wheel hardware, then confirm that the tires are mounted in the correct size for the sub-model. A quick check of inflation pressure, visible sidewall condition, tread seating, and any sign of rubbing is also worthwhile before the first road miles.

A short test drive should be followed by another look at clearance and air retention, especially on an older car that may have worn suspension parts or wheels with decades of use behind them. Listen for contact during turns and check for uneven stance or unusual steering feel. Catching those issues early is much easier than diagnosing them after a longer drive.

Collector-car tires on a 1978 Oldsmobile Starfire should be maintained with regular pressure checks, periodic visual inspection, and careful storage habits. Even when the car is driven infrequently, the tires still need attention for cracking, weathering, bulges, cuts, and slow air loss. Low annual mileage does not prevent age and storage conditions from affecting tire condition.

Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the tires between drives. It is also smart to inspect tread and sidewalls before every road outing, especially at the start of a driving season. A Starfire that sits for long periods benefits from routine condition checks just as much as one that is driven often.