1979 Mazda Tire Fitment Guide

1979 Mazda vehicles use eight sizes across three model lines. The B2000 uses 195R14, 6.00-14, and ER70-14, all on 14-inch rims. The GLC uses 155R13, 6.15-13, and 175/70R13, all on 13-inch rims. The RX-7 uses 165R13 on a 13-inch rim and 185/70R15 on a 15-inch rim. Rim width guidance appears on some radial products: 155R13 fits 4.00- to 5.50-inch rims, 175/70R13 fits 4.5- to 6.0-inch rims, 165R13 fits 4.50- to 6.00-inch rims, and 185/70R15 fits 4.5- to 6.5-inch rims depending on the tire.

The practical takeaway is that 1979 Mazda fitment is model-specific, not year-wide. A B2000 owner needs to stay within 14-inch truck fitments, a GLC owner needs the 13-inch compact-car sizes, and an RX-7 owner must verify whether the car is on 13- or 15-inch wheels before going further. Once the model and wheel diameter are confirmed, the remaining choice usually comes down to construction style, sidewall appearance, and how closely you want to stay to a period presentation.

On a 1979 Mazda, 6.00-14 is a numeric bias-ply size. The 6.00 refers to the tire's nominal section width in inches, while 14 is the wheel diameter in inches. The dash format and the absence of an R identify it as a bias-ply convention rather than a modern metric radial size. For 1979 Mazda fitment, 6.00-14 belongs to the B2000 and mounts on a 14-inch wheel.

That matters because a numeric bias-ply size carries a different look and driving character than the radial alternatives used on other 1979 Mazda fitments. A B2000 owner choosing 6.00-14 is usually aiming for original-era appearance and construction rather than a modernized feel. Before final selection, make sure the wheel itself is the correct 14-inch rim and compare the tire's intended use with how the truck will actually be driven.

No. 1979 Mazda models split into distinct fitments by model line. The B2000 uses only 14-inch sizes, the GLC uses only 13-inch sizes, and the RX-7 uses radial sizes that span both 13- and 15-inch wheels. None of the eight sizes is shared across all three models, so there is no one-size answer for the entire 1979 Mazda range.

That means identifying the model is the first step, even before deciding on bias-ply versus radial construction. A buyer who only knows the year and make can easily end up in the wrong wheel diameter, especially with the RX-7. If your car or truck has had wheel changes over the years, confirm the actual rim diameter on the vehicle as well as the model name before choosing a tire.

For a 1979 Mazda B2000, 6.00-14 and ER70-14 serve different goals even though both fit 14-inch wheels. The 6.00-14 is a traditional numeric bias-ply size, while ER70-14 is a radial in an alphanumeric format. Firestone offers ER70-14 in Bias Look Radial construction with either Redline or RWL sidewall styling, giving it a period-inspired appearance with radial construction underneath.

A B2000 owner focused on original-era presentation will usually lean toward the numeric bias-ply size, while a driver who wants a radial construction with vintage styling cues may prefer ER70-14. The two sizes should not be treated as interchangeable by name alone, though, because they represent different sizing systems. Match the tire to your wheel diameter, intended use, and the visual character you want the truck to carry.

1979 Mazda tires span several sidewall looks depending on size. ER70-14 for the B2000 is available with Redline and RWL styling, while 155R13, 175/70R13, and 165R13 appear in Blackwall form. The 185/70R15 size used on the RX-7 is available in both Blackwall and Wide Whitewall versions. That creates a noticeably different appearance even within the same year and make.

For a late-1970s Japanese car or truck restored with an original-market look in mind, blackwall tires are usually the most natural visual choice. Redline, raised white letter, or wide whitewall treatments can shift the presentation toward a custom, sport, or period-personalized style instead. The right sidewall is often less about fitment than about matching the era, the vehicle's character, and the owner's restoration goal.

1979 Mazda fitments are covered by Firestone, Michelin, Dunlop, Avon, and BFGoodrich, depending on size. Firestone covers ER70-14, Michelin and Dunlop cover 155R13, Avon covers 175/70R13, Michelin and Dunlop cover 165R13, and Michelin, Dunlop, Avon, and BFGoodrich cover 185/70R15. The brand mix is broader on the RX-7's 15-inch radial size than on the compact-truck and compact-car sizes.

Brand choice often comes down to the visual style and intended driving character of the tire rather than a simple right-or-wrong answer. Some 1979 Mazda owners want a traditional European-style blackwall radial for a sports or import presentation, while others want an American period-style sidewall treatment for a custom look. Start with the correct model and size, then compare the available brands within that fitment for the appearance and construction you prefer.

For a 1979 Mazda RX-7 using 185/70R15, Michelin XWX and BFGoodrich Silvertown Radial differ most clearly in sidewall style and published service details. The Michelin XWX is a blackwall radial in size 185/70VR15 89V TL, while the BFGoodrich Silvertown Radial is a wide whitewall radial in 185/70R15. BFGoodrich also publishes a maximum load figure of 1257 pounds at 35 psi, and both Michelin and BFGoodrich fit 5.00- to 6.50-inch rims where rim-width guidance is given.

That makes the choice less about basic fitment and more about the personality you want the car to project. The Michelin XWX suits an owner chasing a classic European-style sporting look, while the BFGoodrich suits a more distinctive custom or period-personalized presentation. Since both sit in the same nominal size, the final check should be your wheel width, sidewall preference, and whether the speed marking on the tire matches how you intend to use the RX-7.

Rim-width guidance is available for several 1979 Mazda radial sizes. The 155R13 used on the GLC fits 4.00- to 5.50-inch rims, 175/70R13 fits 4.5- to 6.0-inch rims, 165R13 used on the RX-7 fits 4.50- to 6.00-inch rims, and 185/70R15 fits either 4.5- to 6.0-inch rims or 5.00- to 6.50-inch rims depending on the tire. All of those figures are size- and product-specific rather than universal across the year and make.

The key is to compare your wheel's actual width with the guidance for the exact tire you want, especially on the RX-7 15-inch size where the approved range differs by brand. Rim width influences how the tire sits, how the sidewall presents, and whether the mounting is appropriate. If your wheels are aftermarket or the vehicle has changed hands many times, measure the wheel before making the final selection.

Inner-tube status varies by size and by product on 1979 Mazda fitments. Some 155R13, 165R13, and 185/70R15 products are marked TL, indicating tubeless construction, while other products in those same sizes do not carry that same marking in the tire description. That means tube use cannot be treated as one blanket answer across all 1979 Mazda tires, and the bias-ply sizes on the B2000 and GLC should be checked carefully against the wheel type and tire specification.

The safest approach is to match the tire's sidewall marking and the wheel's construction before installation. Original steel wheels, restored wheels, and later replacement wheels do not always present the same sealing and safety considerations. If you are maintaining a factory-style setup on a low-use collector Mazda, a tire shop familiar with vintage applications can help confirm whether the chosen tire should be run tubeless or with a tube.

Original 1979 Mazda wheels cannot be treated as universal across all tire sizes because the model range spans three rim diameters. B2000 sizes are 14-inch fitments, GLC sizes are 13-inch fitments, and RX-7 fitments split between 13- and 15-inch wheels. A tire must match the wheel diameter exactly, regardless of whether the tire is bias-ply or radial.

Within a single model, wheel interchange depends first on diameter and then on whether the wheel width falls within the approved range for the specific tire. That is especially important when moving between narrower and wider radial sizes on 13-inch wheels or selecting among the 185/70R15 options for the RX-7. Confirm the wheel actually on the vehicle before assuming an original wheel and the intended tire are compatible.

A 1979 Mazda should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment that can age rubber. Keep the tires properly inflated and move the vehicle periodically so it does not rest on one footprint for months at a time. The bias-ply sizes used on the B2000 and GLC are especially prone to flat-spotting during long static storage compared with the radial fitments elsewhere in the 1979 Mazda range.

If the vehicle will sit for an extended period, some owners use tire cradles or stands to reduce stress on the casing, but the car or truck still needs to be supported correctly and safely. Storage habits matter just as much as mileage on collector vehicles. Good storage preserves sidewall appearance, ride quality, and service life, especially on a Mazda that may spend more time parked than driven.

Tires on a 1979 Mazda should be judged more by age and condition than by miles driven. A useful rule is to begin evaluating them closely at about five to seven years of service and to give serious replacement consideration by around ten years, even if the tread still looks good. That applies to both bias-ply and radial collector tires because rubber hardens and internal materials age whether the vehicle is driven often or not.

The date code on the tire is the first thing to check, followed by sidewall cracking, tread separation signs, vibration, and the tire's ability to hold pressure. An RX-7 or GLC that sees occasional pleasure use can age out its tires long before it wears them out. A B2000 kept as a restoration piece can do the same, particularly if it has spent years in outdoor or ozone-heavy storage.

Tires on a 1979 Mazda should be inspected before every drive and again before any longer outing. Look for sidewall cracking, weathering, tread damage, bulges, uneven wear, and any sign that the tire has lost pressure since the last use. On fitments that may use tubes, valve stems and slow leaks deserve extra attention because a car that sits between drives can hide small air-loss problems until the next trip.

A quick visual check in the garage catches many of the problems that strand collector vehicles on the road. It also gives you a chance to confirm that all four tires still match in size, construction, and general age if the car has been through multiple owners. That simple routine is especially worthwhile before taking a low-mileage 1979 Mazda on an event run or highway drive after a long period of storage.

For a 1979 Mazda B2000, the period-correct construction baseline is bias-ply, reflected here by the 6.00-14 size, while radial alternatives such as 195R14 and ER70-14 represent the broader transition toward radial fitments that was underway by the late 1970s. Compact trucks of that era could vary by market, trim expectations, and owner preference, so the exact original fitment should be confirmed against surviving factory literature or marque-specific references.

A restoration owner should treat 6.00-14 as the natural starting point for an original-style presentation and view the radial sizes as alternate period-era directions rather than identical substitutes. Sidewall style matters too, especially if the truck is being judged or presented at a marque-focused event. For the final call on what is correct for a specific B2000 configuration, consult factory brochures, marque clubs, or an experienced Mazda truck specialist.

Correct tire fitment absolutely matters when showing a 1979 Mazda, especially if the vehicle is entered in an originality-focused class. Judges and knowledgeable enthusiasts often notice whether the size matches the car or truck, whether the construction is appropriate to the era, and whether the sidewall style looks right for the vehicle's intended presentation. A modern radial on a car judged for factory authenticity, or a dramatic whitewall on a car that historically wore blackwalls, can change how the restoration is received.

That does not mean every show car needs the same tire, because a B2000, GLC, and RX-7 each carry different expectations. The right answer depends on whether your goal is factory-correct restoration, period personalization, or a driver-level presentation that only nods to originality. Event rules differ, so marque clubs and judging manuals are the best place to confirm how size, construction, and sidewall details will be evaluated.

For a 1979 Mazda RX-7 using 165R13, Michelin XAS-FF and Dunlop SP Sport Aquajet share the same basic fitment theme: both are blackwall radials in an older Euro-metric size and both carry H speed ratings with a 130 mph ceiling. Michelin marks the XAS-FF as 165HR13 82H TL and gives a 4.50- to 6.00-inch rim-width range, while Dunlop gives a 1,047-pound maximum load figure for its 165R13 82H product. Both belong to the same classic import-size family, but they present their technical details differently.

That means the decision is less about whether one fits and the other does not, and more about which style of vintage radial specification best matches your restoration or driving priorities. If rim width confirmation is your main concern, Michelin gives a direct wheel-width window. If load specification is part of your comparison, Dunlop puts that figure front and center. Either way, keep the tire choice aligned with the RX-7's wheel size and intended presentation.

1979 Mazda tires can be appropriate for highway use when they are the correct size, in sound condition, and matched to the vehicle's wheels and intended driving. Several radial fitments carry H speed ratings, which correspond to a 130 mph ceiling, while some 185/70R15 options carry V ratings, which correspond to a 149 mph ceiling. Those speed capabilities exceed normal highway travel, but the vehicle's own age, suspension condition, alignment, and braking system remain just as important as the tire itself.

A well-sorted RX-7, GLC, or B2000 should still be driven with the expectations of a late-1970s vehicle, not a modern one. Bias-ply tires also ask for a different mindset than radials, especially in tracking and transient feel. Before any sustained highway use, check age, inflation, wheel condition, and the overall mechanical state of the Mazda so the tire is only one part of a safe road setup.

Inflation pressure on a 1979 Mazda should follow the vehicle's factory recommendation first, with the tire maker's maximum-pressure marking used only as a service limit rather than a blanket operating target. One 185/70R15 BFGoodrich radial carries a load figure of 1257 pounds at 35 psi, and the same size from Dunlop carries a 1,279-pound maximum load figure. Those figures belong to those individual tires and should not be transferred to the B2000's 14-inch sizes, the GLC's 13-inch sizes, or the RX-7's 165R13 fitment.

The practical rule is simple: use the owner's manual or factory placard to establish the vehicle's intended cold pressure, then confirm that the selected tire supports the car or truck properly at that setting. If the vehicle is running a reproduction or specialty tire, compare the manufacturer's guidance as well. Pressure that is right for one size or one construction can be wrong for another, even within the same year and make.

Before a longer drive in a 1979 Mazda, inspect all five tires if the spare is still carried. Check for cracking, cuts, bulges, uneven tread wear, and any sign of impact damage or age-related hardening. Confirm cold inflation pressure, look closely at valve stems, and pay extra attention if the car or truck uses a tube-type arrangement or has sat for months between outings. A spare that has old tread but severe age cracking is not road-ready simply because it appears unused.

Tire condition should be part of a broader pre-drive routine on any late-1970s vehicle. Wheel fasteners, brakes, wheel bearings, shocks, and steering components all affect how safely the Mazda will use the tire you choose. Once the basics are covered, take the first few miles gently and feel for vibration, pull, or heat buildup so small issues can be caught before they turn into a roadside problem.