The 1979 Ford Mustang II sits at an interesting point in Mustang history, carrying late-1970s styling and trim variety while bridging the move from older domestic tire sizing into newer radial and metric fitments. That matters here, because this exact year and model uses several different tire sizes depending on engine, trim, and wheel setup, including both bias-ply and radial constructions. Sizes range from 13-inch and 14-inch alphanumeric fitments to the millimetric 190/65R390 used on the Cobra. The right choice starts with identifying the exact sub-model and wheel, then deciding whether the goal is period-style appearance, restoration-oriented presentation, or road use with the proper construction and fitment checks.
Which Tire Size Is Right for The 1979 Ford Mustang II
The 1979 Ford Mustang II does not use one universal tire size. Six primary sizes appear across the range, and they vary by sub-model, construction type, and wheel diameter, including both 13-inch and 14-inch fitments plus a millimetric radial setup. Identifying the exact sub-model is important, but confirming the actual wheel diameter matters just as much before selecting a tire.
B78-13 is a vintage alphanumeric bias-ply size in which the letter identifies the tire's size class, the series number refers to its profile family, and 13 indicates a 13-inch rim. On the 1979 Ford Mustang II, it represents one of the smaller bias-ply fitments used on certain four-cylinder and Turbo Non-Air applications. This size also has modern radial equivalents available in several formats, including metric, P-metric, and bias-look radial alternatives. It is the size to evaluate when the car retains its original-style 13-inch wheel setup and a traditional bias-ply presentation is part of the goal.
C78-13 follows the same vintage alphanumeric bias-ply sizing system, with the final 13 identifying a 13-inch rim. Within the 1979 Ford Mustang II range, this size appears on several sub-models and serves as another traditional bias-ply fitment for cars equipped with 13-inch wheels. Its importance is less about brand or sidewall choice here and more about making sure the car actually belongs to a 13-inch bias-ply application rather than one of the 14-inch or radial setups. It is a useful reference point for buyers keeping a period-style tire construction on the correct wheel diameter.
C78-14 is a vintage alphanumeric bias-ply size, with the letter marking the size class, the series number indicating the profile family, and 14 showing rim diameter. On the 1979 Ford Mustang II, this is a 14-inch bias-ply fitment used on the 8 Cyl. application. Radial equivalents are available for this size as well, including 175R14, P185/75R14, and P195/70R14, which gives buyers more than one way to approach replacement sizing. This is the size to verify when the car is an 8-cylinder model and the decision involves keeping a bias-ply format or comparing radial alternatives carefully.
190/65R390 is a metric radial size, with 190 representing nominal section width in millimeters, 65 indicating aspect ratio, R identifying radial construction, and 390 referring to a millimetric wheel diameter rather than a standard inch-based rim. On the 1979 Ford Mustang II, this size is tied to the Cobra and reflects the specialized Michelin TRX setup used on that application. The available product is a Michelin TRX-B blackwall radial from the Michelin TRX series. This size requires especially careful wheel confirmation because a 390mm TRX wheel is not the same as a conventional 14-inch or 15-inch rim.
Fit(s): Ghia 8 Cyl., Ghia All Models Except 8 Cyl., and Turbo w/Air
Construction: Radial|Rim: 14 in
CR78-14 is an alphanumeric radial size in which the size class and profile are built into the letter-and-number designation, while the R confirms radial construction and 14 indicates a 14-inch rim. On the 1979 Ford Mustang II, it appears on certain Ghia and Turbo w/Air applications as a primary radial fitment rather than a radial conversion from a bias-ply size. Its role in the range is important because it separates those cars from the 13-inch bias-ply setups and from the millimetric Cobra TRX arrangement. This is the right size to confirm when the car already uses a conventional 14-inch radial application.
BR78-14 uses the vintage alphanumeric radial format, with the R indicating radial construction and 14 designating a 14-inch rim. Within the 1979 Ford Mustang II lineup, it serves as one of the radial fitments used on Ghia models other than the 8 Cyl. application. Its presence shows that even within one trim family, tire selection can depend on the exact configuration rather than the model name alone. This is the size to focus on when the car is a non-8-cylinder Ghia and the goal is to stay with the correct type of 14-inch radial fitment for that setup.
Sub-model fitment for the 1979 Ford Mustang II varies considerably, so tire selection is not as simple as choosing by model name alone. Engine, trim, and special package differences can change both the size and the construction, which makes the exact sub-model and wheel setup the first things to confirm.
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1979 Ford Mustang II 4 Cyl.
The 1979 Ford Mustang II 4 Cyl. uses 13-inch bias-ply fitments, with either B78-13 or C78-13 depending on the car's setup. That makes wheel confirmation especially important before choosing between a traditional bias-ply presentation and a radial-equivalent path where one exists.
The 1979 Ford Mustang II 6 Cyl. uses the C78-13 bias-ply size. Tire selection for this sub-model centers on keeping the proper 13-inch bias-ply format and confirming that the car has not been changed to a different wheel diameter over time.
The 1979 Ford Mustang II 8 Cyl. uses the C78-14 bias-ply size on a 14-inch wheel. That gives this sub-model a different fitment path than the 13-inch cars, and it also opens the door to evaluating the available radial equivalent sizes carefully.
The 1979 Ford Mustang II Cobra uses the 190/65R390 radial size, which is a millimetric TRX-type fitment rather than a standard inch-based wheel setup. Tire selection here starts with verifying that the car still has its 390mm wheels before considering any replacement.
The 1979 Ford Mustang II Ghia 8 Cyl. uses the CR78-14 radial size. This sub-model belongs to the conventional 14-inch radial group, so the key is selecting the correct radial format rather than assuming it shares the same tire approach as the bias-ply cars.
1979 Ford Mustang II Ghia All Models Except 8 Cyl.
The 1979 Ford Mustang II Ghia All Models Except 8 Cyl. uses 14-inch radial fitments, with BR78-14 or CR78-14 depending on configuration. That means the Ghia name alone is not enough for tire selection, and the exact application should be confirmed before choosing a replacement.
The 1979 Ford Mustang II Turbo Non-Air uses 13-inch bias-ply fitments, either B78-13 or C78-13. Buyers working with this sub-model should verify the actual wheel and size already on the car before deciding between a traditional bias-ply appearance and any radial-equivalent alternative.
The 1979 Ford Mustang II Turbo w/Air uses the CR78-14 radial size. That places it in the 14-inch radial fitment group, making wheel diameter and correct radial sizing more important than bias-ply replacement considerations.
Bias-Ply to Radial Tire Conversion for the 1979 Ford Mustang II
B78-13 and C78-14 each have four radial-equivalent pathways to consider. For B78-13, the options are 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; the recommended rim-width range is 4-6 inches. For C78-14, the options are 175R14, P185/75R14, and P195/70R14, also with a 4-6 inch recommended rim-width range. These equivalents should still be checked against wheel type, dimensions, and clearance before changing setups.
Modern Radial Equivalents
175R13
Equivalent 80-series Metric Radial (B78-13)
P175/75R13
Equivalent P-metric 75-series Radial (B78-13)
P185/70R13
Equivalent P-metric 70-series Radial (B78-13)
650R13
Bias-look Radial Equivalent (B78-13)
175R14
Equivalent 80-series Metric Radial (C78-14)
P185/75R14
Equivalent P-metric 75-series Radial (C78-14)
P195/70R14
Equivalent P-metric 70-series Radial (C78-14)
Important Considerations When Replacing Bias Ply With Radial
Compare overall diameter and section width carefully to ensure proper fit.
Verify recommended rim range (4-6 in) and load needs match your vehicle specifications.
Check fender clearance, steering clearance, and stance before installation.
Consider suspension condition and intended road use when choosing equivalents.
Important Fitment Notes
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 Ford Mustang II Tires for Sale
Available product coverage for the 1979 Ford Mustang II centers on the Cobra's 190/65R390 TRX fitment. That setup is represented by a Michelin radial in the Michelin TRX-B series with a blackwall sidewall, making wheel type the key comparison point before product details.
Owners of a 1979 Ford Mustang II usually need to sort out exact tire size, wheel diameter, and whether the car belongs to a bias-ply, conventional radial, or TRX millimetric fitment. The questions below focus on those decisions, along with radial equivalents, appearance choices, and road-use checks.
Tire Size & Fitment
What tire size fits a 1979 Ford Mustang II?
A 1979 Ford Mustang II can use B78-13, C78-13, C78-14, 190/65R390, CR78-14, or BR78-14 depending on the exact sub-model and wheel setup. That range includes both bias-ply and radial constructions, plus both inch-based and millimetric wheel fitments.
The first step is narrowing the car down by sub-model, then confirming the actual wheel diameter on the vehicle. A Mustang II Cobra with 190/65R390 requires a very different tire approach than a 13-inch bias-ply four-cylinder car or a 14-inch radial Ghia, so one size should never be assumed across the full model range.
What size rim does a 1979 Ford Mustang II use?
The 1979 Ford Mustang II uses more than one wheel size. Its primary tire fitments include 13-inch and 14-inch rims, and the Cobra's 190/65R390 radial uses a 390mm millimetric wheel rather than a standard inch-based rim.
Checking the wheel itself is important before selecting any replacement tire, especially on cars that may have been changed over the years. A tire meant for a conventional 14-inch rim is not the same as a TRX tire for a 390mm wheel, even though the dimensions may seem close at a glance.
Why does the 1979 Ford Mustang II have more than one tire size?
The 1979 Ford Mustang II was offered in several sub-models, and those configurations did not all share the same tire and wheel package. Four-cylinder, six-cylinder, eight-cylinder, Cobra, Ghia, and Turbo versions span different sizes, different rim diameters, and both bias-ply and radial constructions.
That means tire selection depends on the exact car rather than the badge on the fender alone. Verifying the sub-model, construction type, and wheel on the vehicle helps prevent confusion between similar-looking alphanumeric sizes and makes it much easier to decide whether to stay original in format or compare an appropriate radial equivalent.
Bias-Ply & Radial Options
Is B78-13 a bias-ply or radial tire for the 1979 Ford Mustang II?
B78-13 is a bias-ply tire size on the 1979 Ford Mustang II. It appears on certain 13-inch applications such as some 4 Cyl. and Turbo Non-Air configurations, where it represents a traditional alphanumeric bias-ply fitment rather than a radial primary size.
That distinction matters because the car's wheel and intended appearance may point toward keeping the bias-ply format, while road-use preferences may lead some owners to study a radial equivalent instead. The next checks should be wheel width, overall vehicle setup, and clearance, rather than assuming every 13-inch Mustang II uses the same construction.
What radial tire sizes are equivalent to B78-13 and C78-14?
B78-13 has four radial-equivalent options: 175R13, P175/75R13, P185/70R13, and 650R13 as a bias-look radial. C78-14 has three radial-equivalent options: 175R14, P185/75R14, and P195/70R14. Both equivalent groups carry a recommended rim-width range of 4-6 inches.
Those choices give different sizing formats and profiles rather than one universal answer. A buyer comparing them should look at the wheel on the car, the construction style desired, and basic clearance around steering and fenders before moving away from the original bias-ply specification.
Should I use bias-ply or radial tires on a 1979 Ford Mustang II?
That depends on which primary fitment the car uses and what the goal is for the vehicle. Some 1979 Ford Mustang II applications are true bias-ply sizes such as B78-13, C78-13, and C78-14, while others are primary radial fitments such as BR78-14, CR78-14, and the Cobra's 190/65R390.
A restoration-oriented owner may prefer to stay with the original construction style used by that sub-model, while a road-use-focused owner may compare an available radial equivalent where one exists. The best path starts with the actual wheel and sub-model, then moves to appearance, driving use, and compatibility checks rather than treating all Mustang II setups the same.
Choosing the Right Tire
What should I consider when choosing a 190/65R390 tire for a 1979 Ford Mustang II?
A 190/65R390 tire for a 1979 Ford Mustang II belongs to the Cobra's millimetric TRX setup, so the first consideration is confirming that the car still has 390mm wheels. This is a radial fitment and is not part of the standard 13-inch or 14-inch inch-based tire group used elsewhere in the Mustang II range.
Once the wheel type is confirmed, compare the available tire's series, sidewall style, and rim-width compatibility with the way the car will be used. This size rewards careful verification because the key decision is not just tire size, but whether the vehicle remains on the specialized TRX wheel system.
What sidewall styles are available for 1979 Ford Mustang II tires?
For the 1979 Ford Mustang II products represented here, the visible sidewall style is blackwall. That applies to the Michelin TRX-B offered in the Cobra's 190/65R390 size, which keeps the presentation straightforward and consistent with a TRX-style radial application.
Sidewall style matters most when the car's appearance is part of the decision, especially on collector vehicles. Even so, sidewall treatment should come after the fitment basics are confirmed, because the right wheel type and correct size are more important than choosing a look that does not belong to the actual tire setup on the car.
What brands offer tires for the 1979 Ford Mustang II?
Michelin is represented for the 1979 Ford Mustang II through the 190/65R390 Cobra fitment. That product appears in the Michelin TRX-B series and reflects the specialized TRX radial setup rather than the conventional inch-based bias-ply and radial sizes used on other Mustang II configurations.
Brand choice should be considered alongside the exact size and wheel system the car requires. On this model, that is especially important because a Cobra on TRX wheels involves a very different replacement path than a 13-inch or 14-inch Mustang II using standard domestic sizing.
Restoration & Appearance
Which tire should I choose for a period-style 1979 Ford Mustang II?
A period-style 1979 Ford Mustang II tire choice starts with the exact sub-model and its original fitment type. Some cars use bias-ply sizes such as B78-13, C78-13, or C78-14, while others use radial formats such as BR78-14, CR78-14, or the Cobra's 190/65R390 TRX setup.
Matching the car to its proper size and construction does more for authenticity than choosing by appearance alone. Owners pursuing exact restoration details should also compare the vehicle against marque references or historical documentation, since a tire can look period-appropriate without necessarily matching the way that specific car was originally equipped.
How does tire construction affect the appearance of a restored 1979 Ford Mustang II?
Tire construction can change the visual character of a restored 1979 Ford Mustang II because bias-ply and radial tires do not present exactly the same way on the car. This model year includes both constructions across its sub-models, so the tire's look should follow the actual fitment used by the specific version being restored.
An owner preserving a traditional late-1970s presentation may want to stay with the proper bias-ply or radial type before considering any equivalent alternatives. Appearance should still be balanced with wheel compatibility and road use, especially if the car has been modified or no longer carries the wheels associated with its original tire format.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1979 Ford Mustang II?
Yes, modifications can affect tire fitment on a 1979 Ford Mustang II. Aftermarket wheels, changes in wheel width, suspension alterations, ride-height changes, or body and fender work can all change whether the original tire size or a radial equivalent remains appropriate on the car.
That matters even more on a Mustang II because the model already spans several wheel and tire systems from the factory, including 13-inch, 14-inch, and 390mm setups. A modified car should be checked for actual wheel diameter, steering clearance, and fender clearance before any replacement size is chosen.
What should I inspect before driving a 1979 Ford Mustang II on new tires?
Before driving a 1979 Ford Mustang II on new tires, inspect the wheels for correct diameter and condition, confirm that the tire size matches the car's actual setup, and check that the tires are properly seated and inflated. It also helps to look at suspension and steering components for looseness that could affect how the car tracks.
A short clearance check is worthwhile as well, especially at full steering lock and over suspension movement. After the first miles, recheck air pressure and look for any signs of rubbing, unusual wear, or air loss so small fitment issues do not become larger problems.
How should tires on a collector 1979 Ford Mustang II be maintained?
Tires on a collector 1979 Ford Mustang II should be kept properly inflated, inspected regularly for cracking, bulges, cuts, and uneven wear, and checked for air loss before road use. Collector cars often sit longer than daily drivers, so age and storage conditions can matter as much as tread depth.
Good storage habits help preserve both bias-ply and radial tires. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources can reduce deterioration, while periodic movement and visual inspection make it easier to catch problems before a tour, cruise, or longer highway drive.
