1975 Mazda Tire Fitment Guide

1975 Mazda vehicles use seven sizes across five model groups. The 808 uses 155R13 or 6.15-13, the B1600 and B1800 use 6.00-14, the Cosmo uses 185/70R14, the RX-3 uses 155R13 or 560-13, and the RX-4 uses 195/70R13 or BR70-13. Rim diameters vary by model, with 13-inch and 14-inch applications both present, so there is no single year-wide size that fits every 1975 Mazda.

That means year and make alone are not enough when choosing tires for a 1975 Mazda. Start by confirming the exact model, then verify whether your car or truck is on a 13-inch or 14-inch wheel before narrowing down construction type and sidewall style. If your model carries more than one acceptable size, use the choice to match your restoration goals and driving habits rather than assuming the biggest overlap across the make will fit your vehicle.

On a 1975 Mazda, 155R13 is a euro-metric radial size. The 155 refers to a 155-millimeter nominal section width, the R identifies radial construction, and the 13 is the wheel diameter in inches. Because there is no stated aspect ratio in the code, this style is conventionally treated as an 80-series radial. In the 1975 Mazda range, 155R13 applies to the 808 and RX-3.

That sizing format matters because it places 155R13 firmly in the radial era, even though the same model might also accept a bias-ply alternative. A buyer comparing 155R13 with 6.15-13 or 560-13 is not simply choosing between equal modern-size expressions; the construction and road feel differ as well. Confirm the wheel diameter and the model first, then compare the radial’s intended character with the more traditional look of the bias-ply options.

No. 1975 Mazda models use different sizes depending on the model, and some use entirely different sizing systems. The 808 and RX-3 both share 155R13 as a radial option, but each also has its own model-specific bias-ply alternative. The B1600 and B1800 pickups use 6.00-14, the Cosmo uses 185/70R14, and the RX-4 uses either 195/70R13 or BR70-13.

That variation is why identifying the exact model matters before comparing brands or sidewall styles. A 14-inch Cosmo or B-series truck fitment should never be assumed interchangeable with a 13-inch 808, RX-3, or RX-4 application simply because the vehicles share the same year and make. Once the model is pinned down, the next question becomes whether the available fitment is a bias-ply, a metric radial, or an alphanumeric radial.

For a 1975 Mazda 808, the choice between 155R13 and 6.15-13 is primarily a choice between radial and bias-ply construction. 155R13 is the radial option, while 6.15-13 is the numeric bias-ply option. They share the same 13-inch rim diameter, but they represent different eras of tire behavior and visual character rather than two identical constructions with different branding.

An owner focused on restoration appearance and a more period-authentic small-car stance may prefer the 6.15-13 route, while an owner planning regular road use may lean toward the 155R13 radial. The same thinking applies when comparing the RX-3’s 155R13 and 560-13 choices. Before deciding, look at the car’s intended use, how original you want it to appear, and whether the current wheel width falls within the product’s approved range.

Sidewall appearance varies considerably across 1975 Mazda sizes. The 155R13 radial options are blackwall tires, the 185/70R14 Cosmo fitment is available in both blackwall and wide whitewall styles, the 560-13 RX-3 bias-ply fitment comes in narrow whitewall and wide whitewall versions, and the 195/70R13 RX-4 radial appears in a narrow whitewall version. That gives buyers a mix of understated sporting looks and more formal period sidewall treatments depending on model and size.

The right sidewall usually follows the personality of the vehicle and the kind of restoration being pursued. A blackwall often suits sportier or European-influenced presentation, while a whitewall can better match a luxury-oriented or more distinctly period-correct American-market look. Sidewall style should be chosen after the correct size is settled, since not every appearance treatment exists in every 1975 Mazda fitment.

Several established brands cover 1975 Mazda fitments. 155R13 is available from Michelin and Dunlop, 185/70R14 is available from BFGoodrich, Avon, Dunlop, and Michelin, 560-13 is available from BFGoodrich and Firestone, and 195/70R13 is available from BFGoodrich. Those brand choices span sport-oriented blackwall radials, formal whitewall radials, and traditional bias-ply designs depending on the size.

Brand selection becomes most useful after you narrow the vehicle to the correct model and size. At that point, the real comparison is usually sidewall appearance, construction type, speed rating, and approved wheel-width range rather than badge preference alone. A Cosmo owner, for example, has a broader mix of brand and style choices than an RX-4 owner staying with 195/70R13, while an RX-3 owner choosing 560-13 is shopping in the classic bias-ply category.

Rim-width guidance is size-specific on the 1975 Mazda range where product specs are available. For 155R13, approved widths reach 4.00 to 5.50 inches on the Michelin application. For 185/70R14, approved widths span 4.5 to 6.5 inches depending on the brand. For 560-13, approved widths run from 3.50 to 4.50 inches depending on the tire, and for 195/70R13 the BFGoodrich radial fits 5.00 to 6.50-inch rims.

That is why wheel diameter alone is not enough. A tire may mount on the correct 13-inch or 14-inch rim diameter but still be a poor match for the wheel if the rim is too narrow or too wide for the product. Check the actual wheel before choosing a tire, especially on cars that may have been changed from factory wheels decades ago or on trucks that have spent years in mixed service.

Tube requirements vary by size and sometimes by product on 1975 Mazda applications. The Michelin 155HR13 and Michelin 185/70VR14 carry TL markings, indicating tubeless construction. Other products in those same sizes do not all repeat that marking, so tubeless status varies by product rather than staying uniform across the entire size. The available 560-13 and 195/70R13 descriptions do not present a single universal tube rule that should be applied across every product variation.

The practical step is to confirm the individual tire’s sidewall marking and then match that to the wheel type you are using. Original wheels, especially on older collector vehicles, may have condition or design factors that influence whether a tube-type setup is appropriate. If your Mazda still wears original rims, it is smart to inspect bead seats, valve holes, and overall wheel condition before finalizing a tube or tubeless installation plan.

Original 1975 Mazda wheels can only be used with the tire sizes that match the correct rim diameter for that model. Some applications use 13-inch wheels and others use 14-inch wheels, so there is no all-model interchange across the year. Even within a model that offers two sizes, such as the 808, RX-3, or RX-4, the wheel still needs to match the tire’s intended diameter and approved width range.

That makes wheel verification especially important on vehicles that have passed through multiple owners. A Mazda may still appear stock while wearing replacement wheels from another trim, another market, or a later repair. Before selecting a tire, confirm the wheel diameter stamped on the rim and compare the actual wheel width against the product requirements for the size you intend to run.

A stored 1975 Mazda should be kept out of direct sunlight, away from electric motors and ozone-producing equipment, and on a clean, dry surface. Proper inflation matters during storage, and the vehicle should either be moved periodically or supported in a way that reduces long-term static loading. Bias-ply tires tend to develop flat-spotting more readily during long rests, while any vintage-style tire can suffer sidewall aging if exposed to heat and ozone.

Storage habits matter just as much as tread depth on a collector Mazda that is driven infrequently. A 560-13 or 6.15-13 bias-ply fitment especially benefits from periodic movement, while radial-equipped cars still need pressure checks and protection from environmental damage. If the car or truck will sit for a season, inspect the spare and the valve stems at the same time so the whole set remains road-ready.

Tires on a 1975 Mazda should be judged more by age and condition than by mileage alone. A collector vehicle can show excellent tread yet still need replacement because the rubber has hardened, cracked, or aged beyond its best service window. As a rule, tires should be evaluated carefully once they are about five to seven years old, and replacement becomes a serious consideration as they approach ten years, regardless of how little the vehicle is driven.

That guideline is particularly useful for low-use classics that may spend months between outings. Check the DOT date code on modern reproduction or radial tires and compare it with the tire’s present condition, not just the car’s odometer reading. A lightly used 1975 Mazda with old tires can still feel fine at neighborhood speeds while carrying age-related risk on a longer drive or in hot weather.

Tires on a 1975 Mazda should be inspected before every drive, with a more thorough check before any extended outing. Look for sidewall cracking, cuts, bulges, uneven wear, embedded debris, and any sign that the tire is losing pressure between drives. On applications that may use tube-type construction or older-style hardware, the valve stem area deserves just as much attention as the tread and sidewall.

Frequent inspection is one of the easiest ways to prevent a small issue from turning into a roadside failure. Collector cars and trucks often sit long enough for pressure loss, weather checking, or flat-spotting to develop without the owner noticing. A few minutes spent checking tire condition before taking a 1975 Mazda out can tell you whether the vehicle is ready for a local drive or needs service first.

A 1975 Mazda 808 could be associated with either a 6.15-13 bias-ply fitment or a 155R13 radial fitment, depending on market expectations and how the car was equipped. In period terms, bias-ply was still familiar while radial adoption was well underway by the mid-1970s, especially on smaller imported cars. That means both construction history and market-specific delivery matter when trying to settle on the most authentic 808 tire.

For a strict restoration, use the tire size and construction that match the car’s original market and presentation rather than assuming every 808 was delivered the same way. Sidewall appearance also affects authenticity, especially if the car is being judged or preserved to a specific regional style. A marque club, original sales literature, or an unrestored reference car can help confirm whether your particular 1975 Mazda 808 should lean radial or bias-ply.

Correct tire fitment absolutely matters when showing a 1975 Mazda. Judges and knowledgeable enthusiasts often notice whether the size, construction type, and sidewall style fit the period and the model’s intended market position. A bias-ply tire on a truck or a small sedan can project one kind of authenticity, while a modern-looking radial or the wrong whitewall treatment can change the car’s visual impression even if the wheel diameter is correct.

The closer the event leans toward concours or marque-focused judging, the more those details matter. A radial fitted where a bias-ply appearance is expected, or a dramatic whitewall on a sporty model that traditionally wore blackwalls, can stand out immediately. Before finalizing a show setup for a 1975 Mazda, compare your chosen size and sidewall style with period photos, marque references, and the standards used by the event you plan to enter.

For the 1975 Mazda RX-3 in 560-13, BFGoodrich offers both narrow whitewall and wide whitewall versions with a 3.50 to 4.00-inch approved rim-width range and an S speed rating, while Firestone offers a wide whitewall version with a 4.00 to 4.50-inch approved rim-width range. All of these are bias-ply tires, and the available load figure shown for each is 850 pounds at 30 psi.

That makes the main differences visual style and wheel-width compatibility rather than a radical change in basic load capacity. If your RX-3 is being restored to a particular look, the whitewall width may decide the issue first. If your wheel width is near one end of the approved range, that can narrow the choice further, so it is wise to measure the wheel before choosing between the BFGoodrich and Firestone versions.

1975 Mazda tires can be suitable for highway driving when the tire’s condition, size, and speed rating match the intended use. The 155R13 and 185/70R14 radial options include H-rated versions with a 130 mph ceiling, the Michelin 185/70VR14 carries a V rating with a 149 mph ceiling, and the BFGoodrich 560-13 carries an S rating with a 112 mph ceiling. Those numbers are well above typical U.S. highway speeds, but age, inflation, and condition matter more than theoretical maximum rating on a collector vehicle.

A 1975 Mazda’s brakes, suspension, alignment, and overall maintenance condition are often the more limiting factors in real-world highway use than the tire’s speed letter alone. That is especially true on older cars that may feel composed at speed but have aged rubber, worn steering parts, or long-dormant wheel bearings. Highway confidence starts with a fresh, correctly matched tire and a sound car, not simply the highest available speed rating.

Inflation pressure on a 1975 Mazda should follow the vehicle manufacturer’s recommendation first, then be checked against the tire maker’s maximum load-and-pressure figures for the exact size you are using. Among the sizes with published load data, 560-13 appears at 850 pounds at 30 psi, 185/70R14 ranges around 1,201 to 1,235 pounds at 35 psi depending on the tire, and 195/70R13 appears at 1,246 pounds at 35 psi. Those figures are load-capacity references, not universal Mazda pressure settings.

Do not transfer one size’s pressure to another simply because the vehicles share the same year and make. A lightweight 808, a rotary coupe, a luxury-oriented Cosmo, and a B-series pickup place different demands on their tires. Start with the factory vehicle guidance if available, then confirm that your chosen tire is being used within its rated pressure range and adjust only with a clear understanding of the vehicle’s weight, wheel, and use.

Before a longer drive in a 1975 Mazda, inspect each tire for cracking, cuts, bulges, irregular wear, and proper cold inflation. Check valve stems, confirm the spare is usable, and make sure each wheel fastener is secure. If the vehicle uses a classic bias-ply fitment or has spent long periods parked, pay extra attention to flat-spotting and any change in ride feel during the first miles.

A tire check should be part of a broader pre-drive inspection on any older Mazda. Fluid levels, belts, hoses, lights, brakes, and charging system health all matter on a car or truck from this era, especially if it has not been driven regularly. The goal is to treat the tire as one critical part of a complete roadworthiness check, not as an isolated item that can be judged by tread depth alone.