1974 Ford Mustang Tires

A 1974 Ford Mustang uses one of three primary 13-inch tire sizes: B78-13, BR78-13, or CR70-13. The correct size depends on the exact Mustang II sub-model. Four-cylinder 2- and 3-door cars can use B78-13 or BR78-13, while several six-cylinder, Ghia, and Mach I applications use CR70-13.

The important step is identifying the car's exact sub-model before selecting a tire. Since all three sizes use a 13-inch rim, the decision is not about wheel diameter alone. It is also about matching the correct size designation and, in some cases, the intended construction type to the vehicle's actual setup.

The 1974 Ford Mustang tire sizes covered here all use a 13-inch rim diameter. That applies to B78-13, BR78-13, and CR70-13. Even though the tire sizes differ by sub-model and construction, the rim diameter stays consistent across these primary fitments.

That common 13-inch diameter simplifies one part of the fitment question, but it does not make every tire size interchangeable. The owner still needs to confirm the correct sub-model fitment and check the actual wheel width on the car, especially if the Mustang has been changed from its original-style wheel setup over time.

No, 1974 Ford Mustang sub-models do not all use the same tire size. Depending on the Mustang II configuration, the car may use B78-13, BR78-13, or CR70-13. Some four-cylinder models allow either a bias-ply or radial fitment, while several other sub-models are tied to CR70-13 radial sizing.

That variation means the sub-model name matters just as much as the model year. A buyer should confirm whether the car is a Mustang II, Ghia, or Mach I configuration and then verify the wheel setup currently on the vehicle. That prevents choosing a tire by rim diameter alone and overlooking the correct size code.

B78-13 is a bias-ply tire size for the 1974 Ford Mustang. It appears on certain Mustang II 2- and 3-door four-cylinder applications, while BR78-13 and CR70-13 are radial fitments used on other covered sub-models. That makes B78-13 the traditional construction choice among this year's primary tire sizes.

Construction affects more than the lettering on the sidewall. An owner keeping a period-style presentation may want to retain the bias-ply format, while someone considering a radial alternative should confirm wheel width, tire dimensions, and clearance before changing construction. That is especially important on collector cars that may no longer wear their original-style wheels.

Radial equivalents for B78-13 include 175R13, P175/75R13, P185/70R13, and 650R13. The first is an 80-series metric radial, the second is a 75-series P-metric radial, the third is a 70-series P-metric radial, and 650R13 is a bias-look radial equivalent for owners who want a more traditional appearance.

Those sizes give a buyer several ways to approach a radial conversion, but they should be treated as alternatives rather than automatic replacements. The recommended rim-width range for the equivalent group is 4 to 6 inches. Wheel width, vehicle clearance, and the car's current ride-height and suspension condition should all be checked before making the change.

Start by confirming that the car currently uses the B78-13 bias-ply fitment and that the radial alternative being considered is one of the established equivalents: 175R13, P175/75R13, P185/70R13, or 650R13. The wheel should also be checked against the 4 to 6 inch recommended rim-width range associated with those equivalent options.

A conversion should also include a close look at tire-to-body and tire-to-suspension clearance, especially on a car with replacement wheels, worn suspension parts, or past modifications. Since the Mustang II lineup used more than one size in 1974, confirming the exact sub-model and present wheel setup helps avoid mixing equivalent logic with the wrong original fitment.

Start with the exact sub-model, because a 1974 Ford Mustang may use B78-13, BR78-13, or CR70-13. The next decision is construction type, since some applications involve a traditional bias-ply size while others use radial sizing. Matching the car's actual wheel setup is just as important as matching the year and model name.

After the correct fitment is confirmed, the choice becomes one of driving intent and appearance. A restoration-oriented car may stay closer to its original tire format, while a road-use-focused car may lead the owner to compare radial options where an established equivalent exists. Wheel width, clearance, and current suspension condition should still be reviewed before final selection.

Choosing among 13-inch tires for a 1974 Ford Mustang starts with separating the three primary fitments rather than treating them as one group. B78-13 is a bias-ply size, while BR78-13 and CR70-13 are radial sizes. That means the correct decision depends first on sub-model application and second on whether the car should retain its original-style construction approach.

Once the right size family is confirmed, compare the tire by its intended role on the car. Some owners prioritize a more traditional visual character, while others focus on maintaining a radial-equipped setup already appropriate to the sub-model. It also helps to inspect wheel width and any prior modifications so the selected tire matches the car as it sits today.

The 1974 Ford Mustang tire fitments here are defined by three vintage size series: B78-13, BR78-13, and CR70-13. In practical terms, that means the car's tire choice is shaped more by the correct size designation and construction type than by a broad mix of overlapping fitments within one simple modern metric category.

For the buyer, the useful takeaway is that each series belongs to a specific fitment path. B78-13 points toward a bias-ply application with radial-equivalent alternatives, while BR78-13 and CR70-13 represent radial applications tied to certain sub-models. Verifying which series belongs on the car prevents choosing a tire that is numerically close but not actually appropriate.

A period-style 1974 Ford Mustang tire choice starts with the size and construction used by the specific Mustang II sub-model. B78-13 suits cars using the bias-ply fitment, while BR78-13 and CR70-13 align with radial-equipped applications. Staying with the proper primary size is the foundation of a restoration-oriented tire decision.

Appearance and driving intent then guide the finer choice. Some owners want to preserve a more traditional bias-ply presentation, while others prefer a radial path that still respects the car's era and wheel diameter. When exact originality matters, it is worth checking marque references or vehicle-specific historical documentation before settling on a final restoration tire approach.

Tire construction can influence the look of a restored 1974 Ford Mustang as much as the size code itself. A bias-ply fitment such as B78-13 tends to support a more traditional vintage presentation, while BR78-13 and CR70-13 place the car in a period radial context. On a Mustang II, that visual distinction can shape the car's overall stance and character.

That does not mean one construction is automatically the right answer for every restoration. The best approach is to begin with the correct sub-model fitment and then decide how closely the finished car should follow its original-style tire format. If a radial equivalent is being considered for a bias-ply application, wheel width and visual expectations should both be reviewed carefully.

Yes, modifications can affect tire fitment on a 1974 Ford Mustang even when the tire size code appears correct. Aftermarket wheels, altered wheel width, suspension changes, ride-height changes, and body repairs can all influence how a B78-13, BR78-13, or CR70-13 tire sits on the car. That matters on a Mustang II because fitment already varies by sub-model.

A careful check should include wheel diameter, wheel width, steering clearance, and space around the fenders and suspension. Collector cars often pick up changes over decades, so the current setup deserves more attention than the badge alone. Confirming those details before mounting new tires helps avoid rubbing, mismatched proportions, or unnecessary fitment surprises.

Before driving a 1974 Ford Mustang on new tires, inspect the wheels for correct diameter and condition, confirm lug hardware and mounting surfaces, and make sure the chosen tire size matches the car's sub-model application. A fresh look at steering movement and visible clearance around the fenders and suspension is also worthwhile before any extended road use.

The rest of the car should not be overlooked just because the tires are new. Check for uneven ride height, worn suspension components, air loss, and any signs that the old tires may have been compensating for another issue. A short initial drive followed by another inspection can reveal rubbing, settling, or pressure changes before longer trips.

13-inch tires on a collector 1974 Ford Mustang should be checked regularly for pressure, tread condition, cracking, cuts, bulges, and signs of slow air loss. Cars that spend long periods parked deserve closer attention because age and storage conditions can affect tire condition even when tread wear remains low. That applies whether the car uses bias-ply or radial construction.

Storage and operating habits make a noticeable difference on low-use collector vehicles. Keeping the car away from prolonged heat, direct sunlight, excess moisture, and ozone sources helps protect the tires over time. It also helps to inspect the tires before each drive rather than only at seasonal intervals, especially on a restored Mustang that is not used daily.