The 1979 Chevrolet Monza came from the final stretch of GM’s compact rear-wheel-drive hatchback era, a period when buyers could still find small domestic cars with distinctly different personalities depending on engine and trim. That matters at the tire level, because the Monza’s fitment is not limited to one size or one construction. This model uses A78-13 and B78-13 bias-ply sizes as well as BR70-13 radial fitment, all on 13-inch rims. That opens the door to a very different look and driving character depending on whether the car retains a vintage alphanumeric bias-ply setup or uses the radial size associated with other configurations. The right choice starts with confirming the exact sub-model and wheel setup before comparing appearance, construction, and replacement options.
Which Tire Size Is Right for The 1979 Chevrolet Monza
Three primary tire sizes apply to the 1979 Chevrolet Monza, and the correct one depends on the exact sub-model and construction type rather than rim diameter alone. All three sizes use a 13-inch rim, but some Monza configurations use bias-ply A78-13 or B78-13 while others use BR70-13 radial tires. Identifying the engine-based sub-model and confirming the actual wheel setup is the first step before choosing a tire.
A78-13 is a vintage alphanumeric bias-ply size in which the letter identifies the tire’s general size class, the 78 refers to its profile family, and the 13 indicates a 13-inch rim. On the 1979 Chevrolet Monza, this is one of the bias-ply fitments used on certain 4-cylinder configurations. Buyers looking at this size are usually balancing correct-era appearance with the characteristics of a traditional bias-ply construction. It is a useful size to evaluate when the goal is to keep a period-style presentation and match the tire type used on the applicable Monza setup.
B78-13 follows the same vintage alphanumeric bias-ply sizing system, with the letter marking the tire’s size class, the series number indicating profile family, and the final number showing 13-inch rim fitment. This size appears across several 1979 Chevrolet Monza configurations, including certain 4-cylinder, V6, and wagon applications. It also carries the broadest equivalent-size path into modern radial formats for buyers considering an alternative construction. B78-13 deserves careful attention when the Monza falls into a shared-fitment group and the tire decision involves both appearance and whether to stay with bias-ply construction.
BR70-13 is an alphanumeric radial size, with the R in the code identifying radial construction rather than bias-ply. On the 1979 Chevrolet Monza, this size is used on 8-cylinder models and also appears on some V6 and wagon configurations, making it an important fitment where the vehicle was already oriented around radial construction. Its meaning is less about vintage bias-ply sizing tradition and more about preserving the radial setup tied to those versions of the Monza. This is the size to focus on when the car’s exact configuration calls for a 13-inch radial rather than a bias-ply alternative.
Sub-model fitment matters on the 1979 Chevrolet Monza because tire choice changes by engine configuration and construction type, even though every primary size uses a 13-inch rim. Some versions stay within bias-ply sizing, while others use radial fitment, so confirming the exact sub-model is the key step before comparing tires.
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1979 Chevrolet Monza 4 Cyl.
The 1979 Chevrolet Monza 4 Cyl. uses bias-ply fitment and can fall into either of two vintage alphanumeric sizes. That makes it especially important to verify the car’s exact existing setup before choosing a period-style replacement or considering a radial equivalent tied to the original bias-ply size.
The 1979 Chevrolet Monza 4 Cyl. w/aluminum wheels follows the same bias-ply fitment pattern as the standard 4-cylinder version, with two applicable vintage alphanumeric sizes. Tire selection starts with confirming which of those sizes is on the car now, then deciding whether appearance or construction change is the bigger priority.
The 1979 Chevrolet Monza 8 Cyl. uses BR70-13 radial fitment on a 13-inch rim. For this sub-model, the tire decision is more straightforward, with the emphasis placed on maintaining the correct radial size and checking wheel condition, suspension clearance, and overall setup before replacement.
The 1979 Chevrolet Monza 8 Cyl. w/aluminum wheels also uses BR70-13 radial fitment. That keeps the main focus on selecting the right 13-inch radial tire for the car’s actual wheel and use pattern rather than sorting between multiple primary size formats.
The 1979 Chevrolet Monza V6 can use either B78-13 bias-ply or BR70-13 radial fitment, so construction choice becomes part of confirming what belongs on the car. Buyers should verify the current wheel and tire setup before deciding whether to retain the traditional bias-ply size or stay with the radial specification.
The 1979 Chevrolet Monza V6 w/aluminum wheels shares the same two-path fitment pattern of B78-13 bias-ply or BR70-13 radial. That means the tire choice is not just about rim diameter, but about confirming which construction and size the car is actually set up to use.
The 1979 Chevrolet Monza Wagon can use B78-13 bias-ply or BR70-13 radial fitment, depending on the vehicle’s configuration. This is a case where checking the existing tire size and overall wheel setup is more important than assuming every wagon uses the same construction.
The 1979 Chevrolet Monza Wagon w/aluminum wheels also spans B78-13 bias-ply and BR70-13 radial fitment. Owners should confirm the exact size already in service before comparing replacement tires, especially when appearance goals and construction preference are both part of the decision.
Bias-Ply to Radial Tire Conversion for the 1979 Chevrolet Monza
A78-13 and B78-13 both have radial-equivalent options for the 1979 Chevrolet Monza. A78-13 corresponds to 165R13 as an 80-series metric radial, P165/75R13 as a 75-series P-metric radial, and P175/70R13 as a 70-series P-metric radial. B78-13 corresponds to 175R13, P175/75R13, P185/70R13, and 650R13 as a bias-look radial. These options differ by sizing convention and profile, with the bias-look radial offering a more traditional appearance. Recommended rim-width ranges are 4-5 inches for A78-13 equivalents and 4-6 inches for B78-13 equivalents, and wheel fit plus vehicle clearance should still be checked carefully.
Modern Radial Equivalents
165R13
Equivalent 80-series Metric Radial (A78-13)
P165/75R13
Equivalent P-metric 75-series Radial (A78-13)
P175/70R13
Equivalent P-metric 70-series Radial (A78-13)
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)
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.
Frequently Asked Questions
Common questions for the 1979 Chevrolet Monza usually center on which of the three primary sizes applies, how bias-ply and radial fitments differ by sub-model, and what to check before changing size or construction on a 13-inch wheel setup.
Tire Size & Fitment
What tire size fits a 1979 Chevrolet Monza?
The 1979 Chevrolet Monza uses three primary tire sizes: A78-13, B78-13, and BR70-13. A78-13 and B78-13 are bias-ply sizes, while BR70-13 is a radial size. The correct one depends on the exact Monza sub-model, since 4-cylinder, V6, 8-cylinder, and wagon configurations do not all share the same tire fitment.
The most important step is identifying the exact sub-model and then confirming what wheel and tire setup is actually on the car. Since all three primary sizes fit 13-inch rims, wheel diameter alone does not answer the question. A Monza that has been changed over the years may also need wheel-width and clearance checks before replacement.
What size rim does a 1979 Chevrolet Monza use?
The primary tire sizes used on the 1979 Chevrolet Monza all correspond to a 13-inch rim. That includes the A78-13 and B78-13 bias-ply sizes as well as the BR70-13 radial size. Rim diameter is consistent across the covered Monza fitments, even though the tire sizes and constructions vary.
That consistency helps narrow the search, but it does not mean every 13-inch tire is appropriate for every Monza configuration. The size code and construction still need to match the sub-model and wheel setup. On a car that has seen wheel changes, the stamped wheel size and actual installed tire should both be checked before ordering replacements.
Why does the 1979 Chevrolet Monza have more than one tire size?
The 1979 Chevrolet Monza has more than one tire size because fitment varies by sub-model and construction type. Some versions use A78-13 or B78-13 bias-ply tires, while others use BR70-13 radials. The difference is not just width or profile on paper; it reflects different tire setups used across the Monza range.
That is why choosing by year and model alone can lead to the wrong result. Engine-based sub-model, wheel setup, and the tire construction already on the car all matter. A V6 or wagon can span both bias-ply and radial paths, so the existing size marking and overall wheel condition should be verified before selecting a replacement.
Bias-Ply & Radial Options
Is A78-13 a bias-ply or radial tire for the 1979 Chevrolet Monza?
A78-13 is a bias-ply tire size on the 1979 Chevrolet Monza. It uses the vintage alphanumeric bias-ply sizing system and appears on certain 4-cylinder Monza configurations. That makes it different from BR70-13, which is the radial size used on other versions of the car.
For an owner, that difference affects both appearance and replacement strategy. Keeping A78-13 means staying with a traditional bias-ply fitment, while moving away from it requires comparing the available radial-equivalent sizes rather than assuming any 13-inch radial is suitable. Wheel width, tire dimensions, and clearance should all be reviewed before a construction change.
What radial tire sizes are equivalent to B78-13?
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. Each one represents a different sizing convention, even though all serve as alternatives to the original B78-13 bias-ply size.
The practical difference is not just the label on the sidewall. Profile style and overall presentation can change from one equivalent to another, especially when comparing a bias-look radial with metric or P-metric options. The recommended rim-width range for B78-13 equivalents is 4 to 6 inches, and actual wheel fit and vehicle clearance still need confirmation.
What should I check before converting my 1979 Chevrolet Monza from bias-ply to radial tires?
Start by confirming the Monza’s exact original size and whether the car uses A78-13 or B78-13 bias-ply fitment. From there, compare only the radial equivalents associated with that specific size, such as 165R13, P165/75R13, and P175/70R13 for A78-13, or 175R13, P175/75R13, P185/70R13, and 650R13 for B78-13.
A careful conversion also means checking wheel width, wheel condition, steering clearance, and fender clearance before settling on an alternative. Collector cars are often no longer exactly as built, and that matters on a compact platform like the Monza. Looking at the current tire’s physical relationship to the body and suspension helps avoid choosing by size code alone.
Choosing the Right Tire
What should I consider when choosing a tire for a 1979 Chevrolet Monza?
The first consideration is the exact tire size and construction that matches the Monza sub-model. A 1979 Chevrolet Monza may use A78-13, B78-13, or BR70-13, and those are not interchangeable simply because they share a 13-inch rim. The decision starts with confirming whether the car is set up for a bias-ply or radial tire.
After that, the real choice becomes how the car will be used and presented. A restoration-oriented Monza may stay closer to its vintage construction style, while a road-driven car might lead an owner to review radial-equivalent options where they exist. Wheel condition, suspension clearance, and the car’s current configuration should guide the final decision.
How do I choose between the available B78-13 tires for a 1979 Chevrolet Monza?
Choosing a B78-13 tire starts with confirming that B78-13 is the primary fitment for the specific 1979 Chevrolet Monza configuration. Once that is established, the main comparison is whether to stay with the vintage alphanumeric bias-ply size or to evaluate one of the radial-equivalent alternatives tied to B78-13.
That choice usually comes down to the car’s purpose. A Monza being kept in a more traditional period-style presentation may point toward the original bias-ply format, while a driver-oriented car may justify reviewing 175R13, P175/75R13, P185/70R13, or 650R13 more closely. Rim-width compatibility and vehicle clearance deserve attention before any change in construction.
What rim-width specifications should I compare when choosing 1979 Chevrolet Monza tires?
Rim width becomes especially important when comparing radial equivalents for the Monza’s bias-ply sizes. A78-13 equivalents carry a recommended rim-width range of 4 to 5 inches, while B78-13 equivalents carry a recommended rim-width range of 4 to 6 inches. That gives a useful wheel-compatibility reference when evaluating alternatives to the original bias-ply sizes.
The next step is matching that range to the actual wheels on the car, not just to the model name. Steel wheels, aluminum wheels, and replacement wheels can differ, and older compact cars are often modified over time. Checking wheel width directly helps narrow the tire options and reduces the risk of choosing a size that does not suit the wheel properly.
Restoration & Appearance
Which tire should I choose for a period-style 1979 Chevrolet Monza?
A period-style 1979 Chevrolet Monza usually starts with the primary size and construction used by that exact sub-model, whether that means A78-13 or B78-13 bias-ply fitment or BR70-13 radial fitment. Staying within the original size family preserves the visual proportions and era-appropriate sizing language that suit a late-1970s compact Chevrolet.
Appearance goals should still be balanced against how the car will be used. A show-oriented Monza may benefit from remaining close to its original construction style, while a regularly driven car may justify reviewing the available radial equivalents for the bias-ply sizes. When exact originality matters, marque-specific restoration references are worth consulting before making a final choice.
How does tire construction affect the appearance of a restored 1979 Chevrolet Monza?
Tire construction can noticeably change the look of a restored 1979 Chevrolet Monza, even when the wheel diameter remains the same. A78-13 and B78-13 use vintage alphanumeric bias-ply sizing, which supports a more traditional late-1970s presentation, while BR70-13 is a radial format that reflects a different visual and fitment character on the car.
That matters because restoration is not only about size but also about stance and sidewall impression. An owner converting from bias-ply to one of the radial equivalents may prefer a bias-look radial if a more traditional appearance is important. The best path depends on whether the Monza is being restored for display, occasional use, or regular driving.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1979 Chevrolet Monza?
Yes, modifications can affect tire fitment on a 1979 Chevrolet Monza even when the car still uses a 13-inch wheel. Changes such as aftermarket wheels, altered wheel width, suspension lowering, or body modifications can all influence how A78-13, B78-13, BR70-13, or a radial equivalent sits in the wheel opening and clears surrounding components.
That is especially important on a compact car where small changes can have a visible effect. Any Monza with non-original wheels or suspension should be checked for steering clearance, fender clearance, and overall tire position before replacement. Looking at the car’s actual current setup is more reliable than assuming every example still matches its original fitment pattern.
What should I inspect before driving a 1979 Chevrolet Monza on new tires?
Before road use, inspect wheel condition, lug hardware, tire pressure, and basic suspension condition on the 1979 Chevrolet Monza. The tires themselves should be checked for proper seating, visible defects, and adequate clearance through the steering range. On an older car, it is also wise to look closely at brake components and wheel bearings while the wheels are off.
A short, careful test drive is the right follow-up after installation. Listen for rubbing, watch for pull or vibration, and recheck air pressure once the car has settled in. Any Monza that has been stored for long periods or driven infrequently deserves extra attention, since dormant chassis and steering issues can show up quickly after fresh tires are installed.
How should tires on a collector 1979 Chevrolet Monza be maintained?
Tires on a collector 1979 Chevrolet Monza should be maintained with regular pressure checks, routine visual inspections, and careful storage habits. Look for cracking, bulges, cuts, uneven wear, or air loss, especially on a car that is driven only occasionally. Older collector vehicles often age tires by time and storage conditions more than by mileage alone.
Good storage makes a real difference. Keeping the Monza away from prolonged sunlight, heat, moisture, and ozone sources helps preserve both bias-ply and radial tires. Moving the car periodically and checking the tires before every outing is also worthwhile, since a low-use vehicle can develop flat spotting, pressure loss, or age-related deterioration without obvious warning.
