Triumph GT6 Tires

Triumph GT6 uses two tire sizes across the full 1967 through 1973 production span: 155R13 and 560-13. Both sizes fit 13-inch wheels, but they represent different construction eras and driving characteristics. The 155R13 offerings are radial tires, while the 560-13 offerings are bias-ply tires. Available 560-13 products also include narrow whitewall and wide whitewall sidewall styles, while 155R13 products are blackwall radials.

The practical choice comes down to how your Triumph GT6 is being used and presented. A car restored for period appearance will usually point you toward 560-13, while a driver-oriented GT6 may lean toward 155R13 for radial behavior. Wheel diameter is not the variable here, since both sizes are built for 13-inch rims. The important next step is to verify the wheel width on the car and decide whether originality or radial handling matters more.

A 560-13 size on a Triumph GT6 is a numeric bias-ply tire designation. The 560 refers to a nominal section width of about 5.60 inches, and the 13 refers to a 13-inch rim diameter. On the available GT6 products in this size, construction is bias-ply and the listed load figure is 850 pounds at 30 psi. Sidewall choices in this size include narrow whitewall and wide whitewall versions.

That matters because 560-13 is the size most closely tied to traditional small sports-car bias-ply fitment and appearance. It is the right direction for a restoration or for an owner who wants the car to feel and sit more like it would have in its original era. Rim width also deserves attention, since available 560-13 products are matched to relatively narrow wheel ranges. A tube is required with this type of bias-ply fitment.

Triumph GT6 uses a 13-inch rim diameter across both listed sizes. The radial 155R13 products are built for 13-inch rims, and the numeric 560-13 bias-ply products are also built for 13-inch rims. There is no wheel-diameter change across the 1967 to 1973 run in the available sizes. The main variation is tire construction and section format rather than rim diameter.

That simplifies fitment compared with many collector cars, because you do not have to sort out an early-versus-late wheel diameter split. Even so, it is still smart to measure the actual wheel and check its width before fitting a new set. The radial products are suited to wider rim ranges than some of the bias-ply products, so wheel width can influence which size works best. Matching the tire to both diameter and width will help the car sit and drive as intended.

Triumph GT6 tube requirements depend on which of the two listed sizes you choose. The 560-13 options are bias-ply tires in a traditional numeric format, and a tube is required with that fitment. The 155R13 products are radial tires and do not carry the same tube requirement statement in the available listings. Because both sizes fit 13-inch wheels, the deciding factor is construction type rather than wheel diameter.

Owners choosing 560-13 should plan the installation as a complete bias-ply setup rather than treating tubes as an afterthought. Tube type, wheel condition, and proper mounting all matter on a low-weight classic like Triumph GT6. If you are moving from bias-ply to radial, inspect the wheels carefully and make sure the tire and rim width pairing is appropriate. Collector cars that sit for long periods especially benefit from careful mounting and regular pressure checks after installation.

Triumph GT6 is listed with both bias-ply and radial choices, so either direction is represented in the available sizes. The 560-13 options are bias-ply tires aimed at period-style fitment, while the 155R13 options are radial tires that keep the same 13-inch wheel diameter. Bias-ply and radial construction do not behave the same way even when the overall fitment is similar. The decision is less about wheel size and more about originality, steering feel, and how the car will be driven.

A concours-minded or visually period restoration will usually favor 560-13, especially if whitewall presentation is part of the build. A GT6 that sees regular road use may benefit from the more familiar response many owners expect from a radial. Either way, keep the choice consistent with the car’s intended role rather than mixing goals halfway through the selection process. Deciding first on restoration accuracy versus driver comfort will make the final size and product choice much clearer.

Yes, moving a Triumph GT6 from a 560-13 bias-ply tire to a 155R13 radial can change the way the car responds on the road. The available radial options use modern radial construction on the same 13-inch wheel diameter, so the difference comes from tire behavior rather than from a wheel-size change. Steering response, straight-line tracking, and general road feel can all differ between the two constructions. That is normal on a lightweight classic sports coupe from this era.

The important point is to treat the change as part of the car’s overall setup, not just a tire swap. A GT6 kept close to factory-era character may feel most cohesive on bias-ply tires, while a car used more often on modern roads may feel more familiar on radials. After any construction change, it is wise to reassess pressures, alignment condition, and suspension wear. Small British sports cars are sensitive to tire behavior, so the driving impression can shift noticeably.

Mixing bias-ply and radial tires on a Triumph GT6 is generally a poor idea because the two constructions flex, track, and respond differently. The GT6 listings include both 560-13 bias-ply and 155R13 radial options, but that does not mean they should be combined on the same car as a casual mix. Construction differences affect steering feel and the way the chassis reacts through corners and braking. Even with the same 13-inch wheel diameter, the car can feel inconsistent if the tire types are mixed.

A better approach is to choose one construction type and fit a matched set. That keeps the handling balance more predictable and preserves either the period bias-ply character or the more modern radial driving feel. If your GT6 currently has mixed tires, make the tire decision part of a broader evaluation of wheel widths, suspension condition, and intended use. Consistency across all four corners is especially important on a short-wheelbase sports coupe.

A 1970 Triumph GT6 can use either 155R13 or 560-13, and that same two-size pattern runs through every model year from 1967 to 1973. Both sizes fit 13-inch wheels, so the decision is not tied to an early-versus-late wheel change. Instead, the choice usually comes down to whether the car is being kept on a period-style bias-ply fitment or moved to a radial setup. Available 560-13 products are bias-ply, while available 155R13 products are radial.

Start by looking at what is on the car now, then confirm the wheel width and decide what role the car plays in your collection. If the goal is original visual character, the 560-13 path usually makes sense. If the goal is road use with radial behavior, 155R13 is the more logical direction. The cleanest result comes from matching all four tires in size and construction rather than changing only one axle.

Triumph GT6 tire offerings include blackwall, narrow whitewall, and wide whitewall sidewall styles. The 155R13 radial products are blackwall tires, while the 560-13 bias-ply products include both narrow whitewall and wide whitewall versions. That gives GT6 owners a meaningful appearance choice without changing the 13-inch rim diameter. Sidewall style is therefore tied closely to the size and construction you choose.

For many GT6 owners, sidewall style is part of the restoration decision as much as the fitment decision. A sportier, later look often points toward blackwall radials, while a more period-presented car may suit one of the whitewall bias-ply options. The key is to decide whether visual authenticity, show presentation, or everyday driving character matters most to your build. Once that is settled, the appropriate sidewall style usually becomes obvious.

The available Triumph GT6 tire brands are Michelin, Dunlop, BFGoodrich, and Firestone. Michelin and Dunlop appear in the 155R13 radial size, while BFGoodrich and Firestone appear in the 560-13 bias-ply size. That spread gives GT6 owners access to both period-style American bias-ply presentation and European-style radial offerings. Brand choice therefore sits within the larger decision about size, construction, and visual style.

The smartest way to use the brand list is not to choose a name first and fitment second. Decide whether the car needs the 560-13 bias-ply route or the 155R13 radial route, then compare the brands that exist within that category. Also pay attention to sidewall style and wheel-width compatibility, because those details can matter more than the badge on the sidewall. On a collector GT6, the right brand is the one that supports the intended look and use of the car.

Triumph GT6 tire offerings span three distinct series: Michelin XAS-FF, SP Sport Aquajet, and classic bias-ply lines from Silvertown and Firestone. The Michelin XAS-FF and Dunlop SP Sport Aquajet are radial-series choices in 155R13, while the Silvertown Classic Bias Ply and Firestone Classic Bias Ply offerings are 560-13 bias-ply tires. The biggest difference between those series is construction type, followed by sidewall presentation and wheel-width range. In short, the series divide along radial-versus-bias lines more than along wheel diameter.

That makes series selection a matter of purpose. Owners who want a classic small-sports-car appearance with traditional behavior will naturally look to the bias-ply series, especially where whitewalls are desired. Owners who plan to drive the GT6 more regularly may gravitate to the radial series, which preserve the 13-inch fitment while changing the tire’s on-road character. Once construction type is settled, compare the available series for sidewall style and rim-width suitability.

A stored Triumph GT6 should be kept in a cool, dry, dark space with the tires protected from sunlight, ozone sources, and long periods of one-position loading. Clean the tires first, set pressures correctly, and keep the car away from electric motors, welders, or other equipment that can accelerate rubber aging. Both radial and bias-ply tires benefit from that treatment, but a low-mile collector car often suffers more from inactivity than from road wear. Proper storage habits can extend useful life and preserve appearance.

If the GT6 will sit for months, move it occasionally or support it in a way that reduces flat spotting and casing stress. Bias-ply tires especially can show storage effects differently than radials, so periodic checks are worthwhile even when the car is not being driven. Avoid parking on damp concrete for long stretches if possible. The goal is to preserve the tire carcass, sidewalls, and shape as carefully as you preserve the paint and trim.

Tires on a Triumph GT6 should be inspected before any meaningful drive and again at regular intervals even when the car is mostly parked. Look for pressure loss, sidewall cracking, tread separation signs, uneven wear, and damage around the bead area. A collector car can appear to have plenty of tread while still developing age-related problems that are easy to miss. Inspection matters equally on 155R13 radials and 560-13 bias-ply tires, although the symptoms can present differently.

A practical routine is to make tire inspection part of every pre-drive check, along with fluid levels and brake feel. On a GT6, small changes in tire condition can noticeably affect the way the car steers and tracks. Pay special attention after long storage, after hitting potholes, or after any change in ride feel. Catching age or casing issues early is far better than discovering them once the car is already out on the road.

Triumph GT6 tires should be replaced when age, cracking, casing deterioration, impact damage, chronic pressure loss, or irregular wear indicate that the structure is no longer trustworthy, even if the tread still looks deep. Collector-car tires often age out before they wear out, especially on lightly used coupes that spend much of their time stored. That rule applies to both the 155R13 radial options and the 560-13 bias-ply options. Visible tread alone is not a reliable measure of tire health on an older classic.

The right habit is to judge tires by condition, age, and specialist inspection rather than by miles alone. If the car has been sitting for years, if the sidewalls show weathering, or if the tire has an unknown service history, replacement should be on the table early. Bias-ply tires and low-use collector tires deserve especially careful evaluation because deterioration can hide beneath a presentable exterior. A fresh-looking sidewall is not enough reason to trust an old tire.

Triumph GT6 is represented here by two period-appropriate fitment directions: 560-13 bias-ply and 155R13 radial. That tells you the car sits in a transition era where both an original-style numeric bias-ply size and a radial metric size are relevant to the model across 1967 to 1973. The available products do not point to a single universal original-equipment brand or one sidewall treatment for every car. What they do show clearly is that 13-inch fitment remained constant while construction choices varied.

For restoration work, the best approach is to decide whether the goal is factory-era presentation, period road use, or a sympathetically updated driving setup. If authenticity is the priority, compare the car against original paperwork, surviving examples, and marque-club knowledge before settling on bias-ply versus radial and on blackwall versus whitewall. Small differences can matter in judged settings. The more precisely the tire matches the car’s intended period character, the more coherent the restoration will feel.

Yes, correct tire fitment can affect how a Triumph GT6 is perceived in both judging and market value, particularly when the rest of the car is restored carefully. Size, construction type, and sidewall style all influence whether the car presents as period-correct or as a driver-oriented interpretation. On the GT6, the visible distinction between a 560-13 bias-ply whitewall option and a 155R13 blackwall radial can significantly change the car’s visual language. Judges and knowledgeable buyers often notice those choices quickly.

That does not mean one style is always right and the other always wrong. It means the tire should match the purpose of the car and the story the restoration is telling. A touring-minded driver build may be entirely credible on radials, while a more historically presented GT6 may be stronger on bias-ply tires with the appropriate sidewall style. If the car will be judged, marque clubs and event standards are the best references for how strict that distinction will be.

Triumph GT6 tires are available here in blackwall, narrow whitewall, and wide whitewall styles, so the correct sidewall depends on the restoration direction you are pursuing. Blackwall appears with the 155R13 radial offerings, while narrow and wide whitewall styles appear with the 560-13 bias-ply offerings. Each creates a different period impression even though all fit 13-inch wheels. Sidewall choice is therefore not just decoration; it is part of the car’s historical presentation.

A GT6 restored as a sharp late-1960s or early-1970s sports coupe will often look most natural on blackwalls, especially if the build leans toward sporting authenticity. Whitewalls can still be a deliberate stylistic choice when the owner wants a different period presentation or a specific visual effect. The important thing is consistency with the rest of the restoration, including ride height, wheel finish, and overall trim level. Tire sidewalls can either reinforce the car’s character or work against it.

Triumph GT6 can be driven on public roads with properly fitted collector tires in the listed sizes, but safety depends on choosing the correct construction, mounting the tires on suitable 13-inch wheels, and making sure the rest of the car is mechanically sound. The available options include both radial 155R13 tires and bias-ply 560-13 tires, and each will give the car a different feel. A fresh, correctly fitted collector tire is very different from an aged tire of unknown history. Condition matters as much as size.

Before road use, think of the tire decision as part of the car’s whole safety system rather than as an isolated purchase. Verify wheel condition, valve hardware, pressure, alignment, and suspension condition, then match your driving style to the construction you selected. A GT6 on bias-ply tires should be driven with expectations appropriate to period behavior, while a radial-equipped car may feel more familiar but still remains a lightweight vintage sports coupe. Respecting the car’s limits is part of using it safely.

Before driving a Triumph GT6, check tire pressure, sidewall condition, visible tread or casing damage, wheel security, and any signs of rubbing or uneven wear. If the car is on 560-13 bias-ply tires, also be sure the tube-type setup was mounted correctly and is holding pressure consistently. On 155R13 radials, inspect for aging and any sidewall distortion from storage just as carefully. Tire condition on a lightly used classic can change during storage as much as during driving.

That quick inspection should be paired with a broader pre-drive routine that includes brakes, steering play, fluid levels, and lights. A GT6 rewards a careful owner, and small faults can become noticeable quickly because the car is compact and responsive. If the car has been parked for an extended period, treat the first outing as a shakedown rather than a normal drive. A few minutes in the garage can prevent a roadside problem and protect hard-to-find components.

Appropriate speed for a Triumph GT6 depends not only on the posted rating or style of tire but also on the age, condition, and construction of the tires actually fitted. A fresh 155R13 radial setup and a fresh 560-13 bias-ply setup will not behave the same at speed even though both fit the same 13-inch wheels. Bias-ply tires generally call for a more measured approach, especially on roads with grooves, crosswinds, or rough surfaces. Collector-car speeds should always be set by condition and stability, not by the car’s theoretical capability.

The safest habit is to build speed gradually and let the car tell you what feels stable and composed. If the GT6 is newly restored, recently fitted with tires, or returning to the road after storage, start conservatively and reassess after a few heat cycles and pressure checks. A vintage sports coupe can be enjoyable well below its limits. Preserving control, predictability, and mechanical sympathy is more important than testing maximum speed on collector tires.