1971 Triumph Tire Fitment Guide

1971 Triumph vehicles use four sizes across four model lines. The GT6 and Spitfire use either 155R13 or 560-13 on 13-inch rims, the Stag uses 185R14 on 14-inch rims, and the TR6 uses 185R15 on 15-inch rims. Rim width ranges where tire fitment is defined are 4.00 to 5.50 inches for 155R13, 3.50 to 4.50 inches across the available 560-13 products, 4.00 to 6.50 inches for 185R14, and 4.5 to 6.50 inches for 185R15.

That spread means a buyer should identify the exact model before worrying about brand or sidewall style. The small GT6 and Spitfire are the only 1971 Triumph models with a true construction choice between bias-ply and radial, while the Stag and TR6 stay in radial territory but on different wheel diameters. If your car has been restored or modified over the years, checking the actual wheel diameter and width before ordering is still a smart final step.

On a 1971 Triumph, 560-13 is a numeric bias-ply size. The 5.60 refers to the tire's nominal section width in inches, and the 13 refers to the wheel diameter in inches. On 1971 Triumph applications, that size belongs to the GT6 and Spitfire, and the available versions use bias-ply construction with whitewall styling rather than modern blackwall radial presentation.

That matters because a 560-13 is not just another way of writing 155R13. It represents a different construction type and a different visual and driving character, even though both sizes fit the same 13-inch wheel diameter family. Owners chasing a period appearance for a small Triumph sports car usually start with 560-13, while owners prioritizing a radial design often compare it directly with 155R13 before making the final choice.

No, 1971 Triumph models do not all use the same tire size. The GT6 and Spitfire share two possible 13-inch fitments, 155R13 and 560-13, while the Stag moves to 185R14 and the TR6 uses 185R15. Those differences separate the model range by wheel diameter as well as by construction choice, since only the GT6 and Spitfire overlap between a bias-ply size and a radial size.

For a buyer, that means year and make are only the starting point. A 1971 Triumph owner still needs to know whether the car is a GT6, Spitfire, Stag, or TR6 before settling on a tire size. That is especially important with restored cars, because a wheel swap from another Triumph model can create confusion if you rely on appearance alone instead of confirming the actual wheel and tire markings.

If your 1971 Triumph is a GT6 or Spitfire, the choice between 155R13 and 560-13 comes down largely to construction and presentation. The 155R13 is a radial blackwall offered by Michelin and Dunlop, while the 560-13 is a bias-ply offered by BFGoodrich and Firestone with narrow or wide whitewall styling. Both belong to the same two small Triumph models, but they represent different eras of tire design and a noticeably different visual effect on the car.

Owners restoring a car toward a vintage showroom or period-accessory look often lean toward the 560-13, especially when whitewall appearance matters. Owners who expect more regular road use often start with the 155R13 because it keeps the original 13-inch wheel format while moving into a radial design. The deciding step is to think about how you want the car to look and feel, then confirm the wheel width matches the tire you prefer.

1971 Triumph tires span several sidewall styles depending on size. The 155R13 choices for GT6 and Spitfire are blackwall radials, while 560-13 brings narrow whitewall and wide whitewall bias-ply options for those same models. The Stag's 185R14 size is available in blackwall and narrow whitewall, and the TR6's 185R15 size adds blackwall, narrow whitewall, and redline choices.

That variety gives owners room to match the tire's look to the car's intended character. Blackwalls usually suit a cleaner European sports-car appearance, while whitewalls and redlines can push the look toward a more period-accessory or individualized presentation. For show use, sidewall style matters alongside size and construction, so it is wise to decide whether your goal is factory-like restraint, a dealer-era accessory look, or a driver-focused presentation before narrowing to a specific product.

Several brands cover 1971 Triumph tire sizes. 155R13 comes from Michelin and Dunlop, 560-13 comes from BFGoodrich and Firestone, 185R14 comes from Michelin, Phoenix, and Vredestein, and 185R15 comes from Coker Classic and Michelin. That mix includes brands closely associated with vintage European and collector-car fitments, along with American classic-tire names that suit period-style bias-ply applications.

Brand choice should be narrowed only after the size and construction are settled, because each size has its own brand mix and sidewall options. A GT6 or Spitfire owner comparing radial and bias-ply choices will often be comparing different brands at the same time, while Stag and TR6 owners are more likely to compare sidewall style, speed rating, and overall presentation within a single radial size. Looking at the car's intended use usually makes that decision easier.

Rim width requirements for 1971 Triumph tires depend on the size. The 155R13 radial fits 4.00 to 5.50-inch rims, 560-13 bias-ply options span 3.50 to 4.50-inch rims depending on the tire, 185R14 fits 4.00 to 6.50-inch rims across the available products, and 185R15 fits 4.5 to 6.50-inch rims. Those ranges are broad enough that the same nominal size can still ask for a slightly different wheel width depending on brand and construction.

That is why wheel measurement matters before ordering, especially on older Triumphs that may no longer wear their original wheels. The GT6 and Spitfire deserve extra attention because their two fitment families overlap in wheel diameter but not in ideal rim width. If your wheel sits near the edge of a tire's approved range, compare the exact product's fitment range rather than assuming every tire in the same size behaves identically.

Inner-tube requirements vary by size and by product for 1971 Triumph tires. The Michelin 155R13 and Michelin 185R14 and 185R15 products carry TL tubeless markings, while other products in those same sizes do not all show the same marking. The bias-ply 560-13 products also do not carry a uniform tube designation across every option, so the right answer depends on the exact tire and the wheel it is being mounted on.

Because wheel condition and wheel design matter just as much as the tire marking, tube decisions should be confirmed before mounting rather than assumed from size alone. On older sports cars, a sound original wheel may still need a closer look at bead-seat condition, valve-stem fit, and whether the wheel was intended for tubeless use. Matching the tire's marking to the actual wheel is the safest way to avoid installation surprises.

A 1971 Triumph should be stored on clean, properly inflated tires in a cool, dry space away from direct sunlight, electric motors, battery chargers, and other ozone sources. Long static storage is especially hard on bias-ply tires such as the 560-13 because they can develop flat-spotting more readily than radials, and any collector tire can suffer sidewall aging if it sits for months in poor conditions. Clean floors and stable temperature matter more than frequent dressing products.

If the car will sit for an extended period, move it occasionally to change the contact patch or use stands in a way that avoids stressing the suspension. Owners of GT6 and Spitfire models on bias-ply tires should be especially patient during the first miles after storage, since temporary flat spots may take time to work out. A breathable cover and routine pressure checks help preserve both the tire and the overall car.

On a 1971 Triumph, tire life is usually judged more by age than by mileage. Collector vehicles often see limited annual use, so a tire that still has tread can still be nearing the end of its service life. A practical rule is to inspect carefully after five to seven years of service and to treat ten years as the point where replacement deserves serious consideration, using the DOT date code and the tire's overall condition as guides.

That age-based approach is especially important for vintage cars that may spend long periods parked between drives. Heat cycles, storage conditions, inflation habits, and exposure to sunlight can matter as much as miles traveled. A lightly used TR6 or Stag can age out a set of radials just as surely as a weekend-driven GT6 or Spitfire can age out a set of bias-ply tires, so replacement timing should never be based on tread depth alone.

Tires on a 1971 Triumph should be inspected before every drive and again before any longer outing. Look for sidewall cracking, tread separation, uneven wear, punctures, bulges, and signs that the tire is losing pressure. On cars using tube-type setups or older wheels, valve stems, rim condition, and any evidence of movement between tire and wheel deserve just as much attention as the tread surface.

Regular inspection is one of the simplest ways to keep a vintage Triumph enjoyable and dependable. A quick visual check in the garage can catch aging issues that are easy to miss on a low-mile collector car, especially if the car was stored for part of the season. If one tire shows unusual wear or pressure loss, inspect the entire set and the suspension alignment rather than replacing or inflating a single corner in isolation.

A 1971 Triumph GT6 belongs to an era when bias-ply was still historically familiar but radial fitments were increasingly common on European sports cars, and both 560-13 bias-ply and 155R13 radial fitments are associated with the model. That makes construction choice an important part of an accurate restoration conversation, especially if the car's market, delivery specification, or restoration goal is narrowly defined. No single original-equipment brand should be assumed without checking period literature for the specific car.

For most owners, the practical lesson is that originality involves more than matching wheel diameter. Construction type, sidewall appearance, and even whether the car should wear a plain blackwall or a more decorative whitewall can affect how correct the finished car looks. If your GT6 is being judged or restored to a precise standard, compare period photos and consult Triumph clubs or marque specialists before making the final call on size and sidewall style.

Correct tire fitment does matter when showing a 1971 Triumph, especially at events that reward factory-correct or period-correct presentation. Judges and knowledgeable enthusiasts often notice whether the car wears the right size family, the expected construction type for the restoration goal, and a sidewall style that suits the era. A modern-looking radial on a car restored to strict early-1970s showroom character, or an overly decorative sidewall on a car meant to look factory-stock, can draw attention for the wrong reasons.

The standard is not always identical from one event to another, which is why event rules and marque-club guidance matter. A driver-quality restoration may reasonably choose a radial for touring, while a concours-minded owner may prefer a size and sidewall treatment that better mirrors period presentation. Knowing how your specific event judges authenticity will help you decide whether construction, sidewall style, or both should take priority.

For the 1971 Triumph TR6, Michelin XVS and Coker Classic both cover the 185R15 radial size, but they differ in presentation and some specifications. Michelin XVS appears in blackwall and narrow whitewall forms, with H-rated 185HR15 and V-rated 185VR15 versions, while Coker Classic appears as a redline 185R15. Rim-width ranges also differ slightly, with Michelin versions spanning 4.5 to 6.50 inches depending on the tire and the Coker Classic spanning 5.00 to 6.50 inches.

That makes the choice less about basic fitment and more about the finished character you want from the TR6. An owner aiming for a clean European touring look may focus on the Michelin options and their available speed-rating spread, while someone who wants a more assertive period-custom visual cue may prefer the redline presentation. Wheel width should be checked before deciding, since the narrower end of the approved rim range is not identical across every 185R15 option.

1971 Triumph tires can be suitable for highway driving when the size, construction, condition, and speed rating all match the way the car is used. The radial sizes here include H-rated products with a 130 mph ceiling and a V-rated 185VR15 with a 149 mph ceiling, while the 560-13 bias-ply options do not carry the same modern speed-letter presentation. In normal collector-car use, the car's age, brakes, suspension condition, and steering integrity are often more limiting than the tire's upper speed ceiling.

Highway safety depends far more on the complete condition of the car than on a single specification. A well-sorted Stag or TR6 on properly maintained radials is a different proposition from a seldom-driven GT6 or Spitfire on aged bias-ply tires, even if the tread still looks respectable. Before any sustained highway run, confirm pressures, inspect the sidewalls, and make sure the car tracks straight and brakes evenly rather than relying on speed rating alone.

Inflation pressure for 1971 Triumph tires should follow the vehicle maker's recommendation for the car and the tire maker's guidance for the exact product. Where tire ratings are marked, the 560-13 bias-ply carries 850 pounds at 30 psi, the 185R14 Phoenix carries 1,323 pounds at 35 psi, the Vredestein 185HR14 carries 1,323 pounds at 51 psi, and the Coker Classic 185R15 carries 1,355 pounds at 35 psi. Those figures are load-and-maximum-pressure references, not a universal setting for every 1971 Triumph.

That distinction is important because one size should never borrow a pressure figure from another. A TR6 on 185R15, a Stag on 185R14, and a Spitfire on 560-13 each deserve their own pressure decision based on the car, the tire, and the intended use. Start with the factory handbook if you have it, then compare that guidance with the tire manufacturer's recommendations for reproduction or modern radial products before settling on a cold inflation pressure.

Before taking a 1971 Triumph on a longer drive, inspect each tire for age cracking, cuts, bulges, exposed cords, uneven wear, and proper cold pressure. Check valve stems, confirm the spare is usable, and make sure the wheel hardware is secure. On any older sports car or grand tourer, tire condition should be part of a broader check that also includes brakes, steering, cooling, and fluid levels, because a healthy tire cannot compensate for neglected mechanical systems.

A longer drive also puts more heat into the tire, so small issues that go unnoticed on a short local trip can become much more important at speed. Cars that have sat for weeks deserve a little extra attention, especially if they are on older bias-ply tires or have recently developed a vibration. Giving the car a slow, deliberate pre-drive walkaround is one of the best habits a collector-car owner can develop.