1970 Triumph Tire Fitment Guide

1970 Triumph vehicles use three sizes across the model range. The GT6 and Spitfire use either 155R13 radial or 560-13 bias-ply tires, both on 13-inch rims. The TR6 uses 185R15 radial tires on 15-inch rims. For rim width, 155R13 products cover 4.00 to 5.50 inches, 560-13 products cover 3.50 to 4.50 inches depending on brand, and 185R15 products cover roughly 4.5 to 6.5 inches depending on the tire.

That means year and make alone are not enough for a correct choice within the full 1970 Triumph range. GT6 and Spitfire owners still need to decide between a radial and a bias-ply approach on a 13-inch wheel, while TR6 owners need the 15-inch radial size specific to that model. Matching the tire to the wheel width already on the car is the most useful next step before narrowing down brand or sidewall style.

On a 1970 Triumph, 560-13 is a numeric bias-ply size. The 5.60 figure is the nominal section width in inches, and the 13 is the wheel diameter in inches. Unlike a modern metric radial size, it does not use the width-aspect-rim format familiar on newer cars. In this year and make, 560-13 belongs to the GT6 and Spitfire rather than the TR6.

That size appeals to owners who want the stance and visual character associated with period bias-ply tires. It is also the size in this group with whitewall choices, including narrow and wide versions. Before choosing one, confirm that the wheel width matches the tire you want, because some 560-13 products are intended for slightly narrower rims than others.

On a 1970 Triumph, 155R13 and 185R15 are metric radial sizes. The first number is the tire width in millimeters, the R indicates radial construction, and the final number is the rim diameter in inches. In period metric sizing like this, the absence of a stated aspect ratio is conventionally treated as an 80-series radial. The 155R13 fits GT6 and Spitfire models, while the 185R15 is the TR6 size.

For a buyer, the important point is that these are not interchangeable just because both are radial. They mount on different wheel diameters and serve different models in the 1970 Triumph lineup. Once the model and wheel diameter are confirmed, the next comparison is sidewall style and, in the case of 185R15, whether you want a blackwall, redline, or narrow whitewall presentation.

For a 1970 Triumph GT6 or Spitfire, the choice between 155R13 and 560-13 is primarily a choice between radial and bias-ply construction on a 13-inch wheel. The 155R13 is a radial blackwall size from Michelin and Dunlop, while the 560-13 is a bias-ply size from BFGoodrich and Firestone with narrow or wide whitewall styling. The TR6 does not use either of these sizes and stays with 185R15.

Owners restoring a GT6 or Spitfire to a more period-authentic presentation often gravitate toward the bias-ply option because construction and sidewall appearance strongly influence how the car looks. Owners planning more regular road use often prefer the radial option for the different driving character associated with radial construction. The deciding factor should be your model first, then whether originality or everyday road manners matters more to you.

1970 Triumph tires come in several sidewall styles depending on size. The 155R13 radial is available as a blackwall. The 560-13 bias-ply for GT6 and Spitfire comes in narrow whitewall and wide whitewall versions. The TR6's 185R15 radial has the broadest appearance range, with blackwall, narrow whitewall, and redline choices.

That variety matters because sidewall treatment changes the personality of a car almost as much as wheel design. A blackwall usually gives the cleanest sporting look, while whitewalls and redlines push the car toward a more period-styled presentation. For a 1970 Triumph being judged for authenticity, sidewall style should be checked against the way the car is being restored, especially if the target is a market-specific or club-level concours standard.

1970 Triumph tire coverage includes Michelin, Dunlop, BFGoodrich, Firestone, and Coker Classic. Michelin and Dunlop cover the 155R13 radial size used on the GT6 and Spitfire. BFGoodrich and Firestone cover the 560-13 bias-ply size for those same models. Coker Classic and Michelin cover the 185R15 radial size used on the TR6.

Brand choice is usually less about broad fitment differences than about sidewall appearance, construction style, and how closely a tire matches the look you want. A GT6 or Spitfire owner deciding between a blackwall radial and a whitewall bias-ply is really choosing between two different visual and driving directions. A TR6 owner has a wider style menu within one radial size, so the comparison is more about presentation and speed rating than basic fit.

Rim width requirements for 1970 Triumph tires depend on the size and product. The 155R13 radial fits rims from 4.00 to 5.50 inches wide. The 560-13 bias-ply covers 3.50 to 4.00 inches in some BFGoodrich versions and 4.00 to 4.50 inches in the Firestone version. The 185R15 radial for the TR6 spans about 4.5 to 6.5 inches depending on the specific tire.

That spread is important because the same wheel diameter does not automatically mean the same wheel width is ideal. Two 13-inch tires can fit very different rim-width ranges, especially when comparing a narrow bias-ply with a radial. Measuring the wheel already on the car, rather than relying on memory or appearance, is the safest way to avoid a mismatch in section shape, sidewall profile, or bead seating.

Tube requirements for 1970 Triumph tires depend on the exact tire. The Michelin 155HR13 and Michelin 185HR15 and 185VR15 examples are marked TL, meaning tubeless. The 560-13 bias-ply products shown here do not use a uniform tube marking in the size description, so tube use should be confirmed against the exact tire and wheel combination before installation. Tube choice is never something to assume across every size or every product family.

The practical point is that tire construction and wheel design both matter. A tubeless tire can still require special attention if it is being mounted to an older wheel, and a vintage-style bias-ply setup may have different needs than a later radial. If your 1970 Triumph still wears original wheels, confirm the tire's sidewall marking and the wheel condition at the same time, rather than treating tube use as a one-size-fits-all answer.

For 1970 Triumph GT6 and Spitfire models, both the 155R13 and 560-13 mount on 13-inch wheels, so the original wheel diameter is compatible with either size. Rim width still matters, though. The 155R13 radial works across a broader 4.00 to 5.50-inch range, while 560-13 bias-ply versions span narrower ranges from 3.50 to 4.50 inches depending on the product.

That means a wheel can be the correct diameter yet still be a better match for one construction than the other. If the car has original wheels, verify width before choosing between the radial and bias-ply options. Doing that first prevents a common vintage-car mistake: selecting a visually appealing size and only later discovering that the wheel is too narrow or too wide for the specific tire you wanted to run.

A 1970 Triumph stores best in a cool, dry, dark space away from direct sunlight, electric motors, welders, battery chargers, and other ozone-producing equipment. Clean concrete is fine if moisture is controlled, but the car should not sit for months with neglected pressure. Bias-ply tires like the 560-13 can develop flat-spotting more readily during long static periods, while radial tires also benefit from regular movement and proper inflation.

For seasonal or low-mileage storage, keep the tires inflated correctly, move the car periodically, and consider stands if the car will be parked for an extended stretch. That matters on a lightweight sports car just as much as on a larger collector car. Good storage habits preserve sidewalls, reduce flat-spotting, and help a 1970 Triumph feel more predictable the next time it goes out on the road.

On a 1970 Triumph, tire age matters more than mileage because many collector cars are driven infrequently. A sensible rule is to evaluate tires closely once they are in the five-to-seven-year range and to treat about ten years as a serious replacement point regardless of tread depth. The DOT date code on the tire is the clearest way to determine age when the tire carries one, and visual condition still matters alongside calendar age.

That approach is especially important for classic sports cars that may look fine while spending much of their life parked. Tread can remain deep long after rubber has hardened or sidewalls have begun to crack. If a 1970 Triumph is used for occasional tours, club events, or highway runs, age-based replacement is a smarter benchmark than waiting for tread wear to tell the story.

Tires on a 1970 Triumph should be inspected before every drive and again before any longer trip. Look for sidewall cracking, tread damage, uneven wear, bulges, embedded objects, and signs that the tire is losing pressure. Valve stems deserve close attention, and if your setup uses tube-type components, the stem area and pressure retention are especially worth watching between outings.

Short local drives can hide problems that become serious once the car is fully warmed up and traveling at sustained speed. A quick walk-around before every outing catches most issues while they are still manageable. For a classic Triumph, that inspection should be treated as part of the same routine as checking fluids, lights, and brake feel rather than as an occasional maintenance chore.

A 1970 Triumph GT6 was built in an era when both bias-ply and radial fitments were part of the conversation, and the correct answer can depend on market and restoration target. Within the 1970 Triumph range, the GT6 uses 13-inch sizes, with 560-13 bias-ply and 155R13 radial options associated with the model. No original-equipment brand should be assumed without model-specific historical confirmation.

For restoration work, the key is deciding whether you are recreating a factory-delivery look for a specific market, or building a car meant to capture the general period character. Construction type, overall appearance, and sidewall treatment can all affect how authentic the finished car looks. If originality matters at a judged-event level, check with a Triumph marque club or model specialist before settling on a final tire style.

Correct tire fitment matters on a 1970 Triumph because judges and knowledgeable enthusiasts often notice construction type, size, and sidewall treatment quickly. A GT6 or Spitfire presented as highly original can look out of period on the wrong sidewall style or on a modern-looking radial if the restoration goal is strict authenticity. The TR6 also benefits from matching tire presentation to the era and character of the car.

That does not mean there is only one acceptable answer for every event. Local shows may reward overall presentation more broadly, while marque-specific judging can be much more exacting about details. If your 1970 Triumph is headed for concours-level scrutiny, verify the expected construction and sidewall appearance for your target class rather than assuming that any vintage-style tire will be treated the same.

For the 1970 Triumph TR6, both Michelin XVS and Coker Classic Radial are offered in 185R15, but they differ in presentation and specification. Coker Classic appears as a redline tire with a 5.00 to 6.50-inch rim-width range and a maximum load of 1,355 pounds at 35 psi. Michelin XVS is available in blackwall and narrow whitewall forms, with H- and V-rated versions, and its rim-width range runs from about 4.5 to 6.5 inches depending on the version.

The real choice is less about whether one fits and more about which look and spec package best matches your TR6. A redline gives the car a distinctly different visual tone than a blackwall or narrow whitewall, and the speed-rating spread within the Michelin line may matter to owners who want a particular period-European touring character. Confirm the exact wheel width and preferred sidewall style before narrowing the choice further.

1970 Triumph tires can be appropriate for highway driving when the size, construction, and condition are correct for the car. The 155R13 products carry H ratings up to 130 mph, while the 185R15 radial family includes H-rated versions to 130 mph and a V-rated version to 149 mph. The 560-13 bias-ply products do not show a modern speed rating in the same way, so they should be treated with the normal caution vintage bias-ply tires deserve.

In real use, the mechanical condition of a 1970 Triumph often matters as much as the tire's speed symbol. Suspension wear, alignment, brakes, wheel condition, and steering play all affect confidence at sustained speed. A sound tire on an unsorted car is not a complete safety solution, so highway readiness should be judged as a whole-vehicle question rather than a tire-only question.

Inflation pressure on a 1970 Triumph should follow the vehicle's factory guidance first, then the tire manufacturer's rated limits for the exact tire being used. Among the available sizes, 560-13 bias-ply tires carry a maximum load of 850 pounds at 30 psi, and the 185R15 Coker Classic radial carries a maximum load of 1,355 pounds at 35 psi. Those figures are load-and-pressure ratings for those specific tires, not universal running pressures for every 1970 Triumph application.

That distinction matters because tire size, construction, and vehicle balance all influence the final pressure choice. A GT6, Spitfire, and TR6 should not be treated as interchangeable just because they are all 1970 Triumph models. Start with the factory recommendation for your exact car, then confirm that the chosen tire is being used within its own pressure and load limits rather than borrowing a number from a different size or product.

Before a longer drive in a 1970 Triumph, inspect each tire for cracking, cuts, bulges, uneven wear, embedded debris, and proper cold inflation. Check that the valve stems are sound, and if your setup involves tube-type components, pay close attention to pressure stability and stem condition. The spare should be inspected as carefully as the four road tires, because an old but unused spare is often the weakest tire on a vintage car.

A longer trip is also a good reason to think beyond the tires. Wheel security, brake condition, coolant, charging system function, and basic roadside tools all matter on a fifty-plus-year-old sports car. Tires are the contact patch, but they work as part of a larger package, and a careful pre-drive inspection helps a 1970 Triumph stay enjoyable rather than turning a club run into a preventable roadside stop.