1979 Buick Skyhawk Tires

A 1979 Buick Skyhawk can use BR70-13, BR78-13, or B78-13, depending on the exact sub-model. BR70-13 and BR78-13 are radial sizes, while B78-13 is a bias-ply size. All of these fitments use a 13-inch rim, but they are not applied uniformly across every covered Skyhawk version.

The first step is identifying whether the car is a Base, Base w/aluminum wheels, S, or S w/aluminum wheels, then confirming the actual wheel and tire setup on the vehicle. That matters because some Skyhawks use two possible radial sizes, while certain S models also bring the bias-ply B78-13 into the picture.

The 1979 Buick Skyhawk uses a 13-inch rim with its covered tire fitments. That applies across BR70-13, BR78-13, and B78-13, so the wheel diameter stays consistent even though the tire size and construction can change from one sub-model to another.

Wheel diameter is only one part of the fitment picture, so it still helps to verify the wheel that is actually on the car. If the Skyhawk has replacement wheels, suspension changes, or a different tire size than expected, the next check should be wheel width and overall clearance before choosing a replacement.

No, 1979 Buick Skyhawk sub-models do not all use the same tire size. Base and Base w/aluminum wheels are associated with BR70-13 and BR78-13 radial fitments, while the S and S w/aluminum wheels are associated with BR70-13 radial and B78-13 bias-ply fitments.

That variation means a replacement tire should be chosen by exact sub-model rather than by year and model alone. It also means construction matters on the S versions, since a buyer may be deciding between keeping a bias-ply style tire or confirming that the car is set up for its radial fitment.

B78-13 is a bias-ply tire size on the 1979 Buick Skyhawk. It appears on certain S sub-model fitments, while BR70-13 and BR78-13 are the radial-size choices used elsewhere in the covered Skyhawk range.

That distinction matters because a bias-ply tire carries a different period look than a radial, and the decision to stay with B78-13 or move toward a radial equivalent should be made carefully. Wheel width, overall dimensions, and clearance should be checked before changing construction, especially on a car that may have seen wheel or suspension changes over time.

Radial equivalents for B78-13 include 175R13, P175/75R13, P185/70R13, and 650R13. Those choices cover an 80-series metric radial, a 75-series P-metric radial, a 70-series P-metric radial, and a bias-look radial that keeps a more traditional visual presentation.

A recommended rim-width range of 4 to 6 inches is associated with those B78-13 radial alternatives. Even with the same 13-inch wheel diameter, an equivalent should still be checked against the car’s actual wheel width, tire-to-body clearance, and intended use before making the switch from the original bias-ply fitment.

Start by confirming that the Skyhawk actually uses the B78-13 bias-ply fitment, since radial sizes also appear as primary fitments on this model. Then compare the intended radial equivalent against the car’s 13-inch wheels, including wheel width, and make sure the tire choice matches the vehicle’s current sub-model and setup.

After that, inspect for practical clearance issues at the fenders, steering, and suspension, especially if the car has aftermarket wheels or any ride-height changes. A radial equivalent can be a useful alternative, but it should be evaluated as a conversion choice rather than treated as an automatic one-size-fits-all replacement for every Skyhawk.

The main considerations are the exact sub-model, the correct primary size, and whether the car is using a radial or bias-ply fitment. A 1979 Buick Skyhawk may call for BR70-13, BR78-13, or B78-13, so the decision starts with matching the car to the proper 13-inch size rather than choosing by appearance alone.

Once the size is confirmed, think about how the car will be used and how original-looking the finished result needs to be. A restoration-oriented owner may want to preserve a period-style presentation, while a driver may be comparing a bias-ply setup with one of the available radial-equivalent directions for B78-13.

Choosing between the available 13-inch tires starts with identifying whether the car needs BR70-13, BR78-13, or B78-13. Those sizes are not interchangeable just because they share the same rim diameter, and the choice also involves construction because the Skyhawk range includes both radial and bias-ply fitments.

After the primary size is settled, compare the tire in terms of its intended look and how closely it matches the car’s current setup. For an S model using B78-13, the question may include whether to stay with bias-ply styling or evaluate one of the named radial-equivalent formats for a different road-use approach.

Rim width becomes especially important when evaluating radial equivalents for the B78-13 fitment. A recommended rim-width range of 4 to 6 inches is associated with those radial alternatives, which gives a useful benchmark when comparing a bias-ply setup to 175R13, P175/75R13, P185/70R13, or 650R13.

The practical reason to check wheel width is that a 13-inch diameter match alone does not settle the fitment question. Measuring the wheels already on the car helps narrow the choice and can prevent clearance or handling surprises, particularly if the Skyhawk no longer has its original wheels or has been modified over the years.

A period-style 1979 Buick Skyhawk tire choice starts with the original fitment path used by the exact sub-model. That could mean staying with BR70-13 or BR78-13 in a vintage radial format, or using B78-13 on an S model where the bias-ply size is part of the covered fitment.

For many restorations, the goal is to preserve the right overall look and size relationship rather than simply install any 13-inch tire. When exact originality matters, vehicle-specific historical references and marque guidance are worth checking, since a period-style match is not automatically the same thing as a verified factory-delivery tire specification.

Tire construction changes the visual character of a restored 1979 Buick Skyhawk because bias-ply and radial tires present differently even when they share the same wheel diameter. On this model, B78-13 carries the bias-ply format, while BR70-13 and BR78-13 represent vintage radial sizing.

That means the construction choice influences whether the car looks more traditional or more in line with a later radial-equipped presentation. An owner restoring an S model should decide early whether the priority is preserving the bias-ply fitment style or moving toward a radial alternative that changes the presentation while staying in the same general fitment family.

Yes, modifications can affect tire fitment on a 1979 Buick Skyhawk even when the car still uses a 13-inch wheel. Aftermarket wheels, different wheel widths, ride-height changes, suspension work, or body modifications can all change how BR70-13, BR78-13, B78-13, or a B78-13 radial equivalent sits in the car.

That is why a modified Skyhawk should be checked at the wheel wells and through the steering range before settling on a replacement tire. Even a size that is correct for the model in stock form should be confirmed against the car’s current wheel position and available clearance rather than assumed to fit unchanged.

Before driving a 1979 Buick Skyhawk on new tires, inspect the wheels, valve stems, lug hardware, and general suspension condition, then confirm that the installed tire size matches the car’s intended fitment. It also helps to check inflation pressure carefully and make sure there is no rubbing at full steering lock or over suspension movement.

A collector-era car can hide age-related issues beyond the tire itself, so a quick road-use inspection should include wheel-bearing feel, brake condition, and any obvious steering looseness. Taking that extra step helps the new tires do their job properly and can reveal fitment or mechanical problems before a longer drive.

Tires on a collector 1979 Buick Skyhawk should be checked regularly for air loss, uneven wear, sidewall cracking, bulges, cuts, and any signs of age-related deterioration. That applies whether the car is using BR70-13, BR78-13, B78-13, or a radial equivalent, because low annual mileage does not stop tires from aging.

Storage conditions matter as much as mileage on a car that spends long periods parked. Keeping the Skyhawk away from prolonged sunlight, excess heat, moisture, and ozone sources can help preserve the tires, and periodic inspections remain important before road use even when the tread still looks barely worn.