1979 Mercury Bobcat Tires

The 1979 Mercury Bobcat uses three primary 13-inch tire sizes: A78-13, BR78-13, and BR70-13. The exact size depends on the sub-model. Runabout Non-Air fitment includes A78-13 bias-ply and BR78-13 radial, while Runabout w/Air and Wagon fitments use BR70-13 and BR78-13 radial sizes.

The important next step is identifying the exact Bobcat configuration before choosing a tire. Since all three sizes share the same rim diameter, the real differences are construction type and profile. A car that has been changed over time may no longer wear the size associated with its original setup, so checking the current wheel-and-tire combination before replacement is a smart move.

The 1979 Mercury Bobcat uses a 13-inch rim with its primary tire fitments. A78-13, BR78-13, and BR70-13 all correspond to a 13-inch wheel diameter, so the rim diameter remains consistent even though the tire sizes vary by sub-model and construction.

That consistency simplifies one part of the fitment process, but it does not make every 13-inch tire interchangeable. Width, profile, and construction still matter, especially when comparing A78-13 bias-ply with BR-series radial sizes. It is worth confirming the actual wheel width on the car as well, particularly if the Bobcat has replacement wheels or a long history of owner changes.

No, the covered 1979 Mercury Bobcat sub-models do not all use the same tire size. The Runabout Non-Air uses A78-13 or BR78-13, while the Runabout w/Air and Wagon use BR70-13 or BR78-13. The shared point is the 13-inch rim diameter, not a single universal tire size.

That means the sub-model name matters before anything else is selected. Even when two versions can use BR78-13, another version may also allow a different size or construction. Checking the sub-model, the wheel on the car, and the existing tire markings helps avoid choosing a size that looks close on paper but does not match the intended setup.

A78-13 is a bias-ply tire size for the 1979 Mercury Bobcat. It appears on the Runabout Non-Air, while BR78-13 and BR70-13 are radial sizes used on Bobcat applications with radial fitment. The difference is built into the sizing format itself, with A78-13 representing the older alphanumeric bias-ply construction.

That distinction matters because construction affects both appearance and the overall feel of the vehicle. An owner trying to keep a more traditional presentation may stay with A78-13, while someone considering a radial alternative should compare the wheel width, current setup, and the intended use of the car rather than assuming any radial size is automatically suitable.

Radial equivalents for A78-13 include 165R13, P165/75R13, and P175/70R13. Those represent three different radial sizing approaches: an 80-series metric radial, a P-metric 75-series radial, and a P-metric 70-series radial. A recommended rim-width range of 4 to 5 inches is associated with those equivalent options.

Each of those sizes gives a different reference point when moving away from a bias-ply fitment, so the choice is not just about matching the 13-inch rim. Wheel width, the car’s present ride height, and available clearance should all be reviewed before conversion. Equivalent sizing is useful guidance, but the car’s actual wheel-and-body setup still needs to be checked.

Start by confirming which Bobcat sub-model you have, which size is on the car now, and whether the existing wheels match the radial size being considered. For an A78-13 application, the radial-equivalent choices are 165R13, P165/75R13, and P175/70R13, with a recommended rim-width range of 4 to 5 inches.

After that, inspect wheel width, tire-to-fender clearance, and steering clearance at full lock. A Bobcat that has different wheels, suspension work, or aging components can react differently than a stock-height car. It also helps to compare the full set rather than one tire at a time so the vehicle keeps a consistent construction and profile approach across all four corners.

The first consideration is the exact sub-model, because the 1979 Mercury Bobcat does not rely on one universal size. Runabout Non-Air fitment can involve A78-13 bias-ply or BR78-13 radial, while Runabout w/Air and Wagon fitments use BR70-13 or BR78-13 radials. Rim diameter stays at 13 inches across the range.

Once the correct size is confirmed, the real decision becomes construction, appearance, and how the car will be used. A bias-ply choice supports a more traditional presentation, while the radial sizes keep the selection within period-style radial fitment. The smartest comparison is between tires that match the car’s sub-model, wheel setup, and overall restoration or driving goal.

Choosing between the available sizes starts with the car itself, not personal preference alone. A78-13 belongs to the Runabout Non-Air bias-ply fitment, BR78-13 is a radial size shared across multiple Bobcat applications, and BR70-13 is used on the Runabout w/Air and Wagon. All three are 13-inch sizes, but they serve different fitment roles.

A good approach is to verify the sub-model, read the tire markings already on the car, and confirm that the wheels have not been changed over the years. That narrows the decision to the size and construction intended for the setup in front of you. From there, appearance goals and radial-versus-bias preferences become much easier to sort out.

Rim width matters because a shared 13-inch diameter does not tell the whole fitment story. For A78-13 radial-equivalent options, a recommended rim-width range of 4 to 5 inches applies to 165R13, P165/75R13, and P175/70R13. That gives a useful reference point when evaluating an A78-13 car for a radial alternative.

The practical takeaway is to measure the wheel rather than relying on assumption, especially on an older Bobcat that may have seen replacement steel wheels or aftermarket upgrades. Width affects how a tire sits and whether the conversion is reasonable for the wheel already on the car. Confirming that detail early can prevent a mismatch later in the process.

A period-style 1979 Mercury Bobcat tire choice starts with the fitment tied to the exact sub-model. A78-13 carries the vintage bias-ply presentation used on the Runabout Non-Air, while BR78-13 and BR70-13 keep the car within the radial sizing formats associated with Bobcat applications from the same model year.

The right direction depends on whether the goal is a traditional bias-ply look and feel or a radial setup that still suits the era of the car. Exact originality claims should be checked against vehicle-specific historical references when that level of restoration matters. For most owners, correct size, correct construction family, and balanced visual proportions are the key priorities.

Tire construction changes more than road feel on a restored 1979 Mercury Bobcat; it also influences the car’s visual character. An A78-13 bias-ply presents the older construction style associated with late-1970s compact-car fitment on the Runabout Non-Air, while BR78-13 and BR70-13 radials give the car a period-style radial look.

That means the tire decision can alter how the Bobcat sits and reads visually even when the wheel diameter stays the same. Owners aiming for a restoration-oriented result usually benefit from choosing the size and construction that align with the sub-model’s intended setup first, then refining the look through brand or product differences where those choices exist.

Yes, modifications can affect tire fitment on a 1979 Mercury Bobcat even though the primary sizes all use a 13-inch rim. Different wheels, altered ride height, suspension changes, or body repairs can influence how an A78-13, BR78-13, or BR70-13 tire sits in the wheel opening and how it clears during steering movement.

A Bobcat that has been lowered, fitted with replacement wheels, or rebuilt with non-stock components deserves a closer check before new tires go on. Wheel width and clearance at the fender and suspension are especially worth reviewing. Small cars can be sensitive to those changes, so measuring the actual setup is safer than assuming it still matches factory-era dimensions.

Before road use, inspect tire pressure, lug-nut tightness, visible clearance around the tire, and the overall condition of the wheels. On a 1979 Mercury Bobcat, it also makes sense to confirm that all four tires match the intended size and construction for the sub-model, especially if the car has changed hands or sat for long periods.

A short local drive can reveal rubbing, pull, vibration, or other setup issues before the car is used more seriously. Collector-era compacts often need a second look at suspension bushings, shocks, and wheel condition after sitting. Catching those details early helps the new tires work as intended and reduces the chance of a problem on the first outing.

Tires on a collector 1979 Mercury Bobcat should be maintained with regular pressure checks, routine visual inspection, and careful storage habits. Look for cracking, cuts, bulges, uneven wear, and signs of air loss. On a low-mileage car, age and storage conditions can become just as important as tread depth.

Keeping the Bobcat away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the tire casing over time. It also helps to inspect the car before each drive rather than assuming infrequent use means everything is fine. A collector car that sits often benefits from more attention, not less, when tire condition is part of the roadworthiness equation.