1979 Triumph Spitfire Tires

A 1979 Triumph Spitfire uses either a 155R13 radial or a 560-13 bias-ply tire. Both sizes are associated with the Spitfire Base and both use a 13-inch rim, so the fitment question is less about wheel diameter and more about which construction style suits the car and its intended use.

That means the next step is confirming how the car is currently set up. A Spitfire already running radial tires may stay with 155R13, while a restoration-oriented car may lean toward 560-13 for a more traditional look. Wheel width should still be checked before choosing among available products, especially if the car has been modified over the years.

The 1979 Triumph Spitfire uses a 13-inch rim diameter with both of its primary tire sizes. That applies whether the car is fitted with the 155R13 radial size or the 560-13 bias-ply size, so rim diameter remains consistent even though the tire construction and sizing format differ.

Rim diameter alone does not settle the whole fitment decision. Wheel width matters as well, particularly when comparing radial and bias-ply products with different approved rim-width ranges. On an older sports car, it is also smart to verify that the wheels currently on the car are the correct diameter and width before ordering tires, since many cars have seen wheel changes over time.

560-13 is a vintage numeric bias-ply size. The 560 designation represents an approximate 5.60-inch nominal section width, and the 13 refers to the wheel diameter in inches. On a 1979 Triumph Spitfire, it identifies the bias-ply fitment option rather than the radial alternative.

For a buyer, that size code signals both an older sizing system and a different tire character than 155R13. It is often chosen for a more traditional appearance, especially when whitewall styling is part of the plan. Because bias-ply and radial tires can call for different wheel-width ranges and present the car differently, the wheel setup and the restoration goal should be considered together.

560-13 is the bias-ply tire size used on the 1979 Triumph Spitfire. The radial primary size is 155R13, so the two fitments differ not only in size notation but also in construction type. That makes 560-13 the traditional option and 155R13 the radial option within the same 13-inch wheel diameter.

Choosing between them affects more than the sidewall lettering on the tire. Bias-ply and radial products in these sizes can have different approved rim-width ranges and a different visual character on the car. A Spitfire being kept close to a period-style presentation may point one way, while a car already set up around radial use may point the other.

Radial equivalents for 560-13 include 155R13 as an 80-series metric radial, P155/75R13 as a P-metric 75-series radial, and P155/70R13 as a P-metric 70-series radial. Those are alternative radial sizing paths for the original bias-ply fitment, and each one uses a 13-inch rim diameter.

The practical difference is that the choices move through different sizing conventions and profile families rather than representing one universal replacement. A recommended rim-width range of 4 to 5 inches is tied to the equivalency guidance, so wheel width, clearance, and the actual stance of the car should be checked before moving from 560-13 into any radial equivalent.

A conversion from 560-13 bias-ply to a radial option starts with the wheel itself. The radial equivalents tied to that original size include 155R13, P155/75R13, and P155/70R13, and the recommended rim-width range attached to that equivalency is 4 to 5 inches.

Beyond wheel width, compare the tire choice against the car's actual clearance at the fenders, suspension, and steering lock. Older sports cars are often altered with replacement wheels, ride-height changes, or suspension updates, and those details matter before changing construction. The goal is to confirm the full wheel-and-tire package, not just match the rim diameter.

Start with the two legitimate fitment directions: 155R13 radial or 560-13 bias-ply. From there, the most important considerations are the car's current wheel setup, whether the goal is road-focused radial use or a more traditional bias-ply appearance, and which sidewall treatment and tire series best suit the project.

Product details help narrow the choice. The available radial options are blackwall tires from Michelin and Dunlop, while the bias-ply options from BFGoodrich and Firestone emphasize classic whitewall presentation. Rim-width approval also differs by product, so the tire should be matched to the actual wheel on the car rather than chosen on appearance alone.

The available sidewall styles for 1979 Triumph Spitfire tires include blackwall, narrow whitewall, and wide whitewall. Blackwall appears with the 155R13 radial offerings, while the 560-13 bias-ply options include both narrow whitewall and wide whitewall versions, giving the car noticeably different visual personalities.

That choice is mainly about presentation once the correct size and construction have been settled. A blackwall radial keeps the look more understated and sports-car oriented, while whitewall bias-ply tires move the car toward a more overt vintage appearance. It is worth deciding how the tire should look on the car before comparing individual products in the same size family.

Michelin, Dunlop, BFGoodrich, and Firestone all offer tires for the 1979 Triumph Spitfire within its supported sizes. Michelin and Dunlop cover the 155R13 radial side, while BFGoodrich and Firestone supply 560-13 bias-ply options in classic series with whitewall styling choices.

Brand selection should still come after confirming the right fitment direction for the car. Once the size and construction are decided, compare the tire series, sidewall style, approved rim-width range, and any useful load or weight figures that matter to your setup. That approach keeps the choice tied to the Spitfire's actual wheel-and-use requirements rather than brand name alone.

A period-style 1979 Triumph Spitfire usually starts with deciding whether the car should present as a radial-equipped late British sports car or lean toward a more traditional bias-ply appearance. The 155R13 radial keeps the car in a classic blackwall sports-car format, while 560-13 bias-ply options emphasize a more vintage visual character.

The right choice depends on the restoration goal rather than one universal rule. Sidewall treatment matters here, because the available 560-13 tires include narrow and wide whitewall styles, which change the car's appearance significantly. If exact originality is important, compare the planned tire choice with marque references and vehicle-specific historical documentation before making the final call.

Tire construction changes the visual tone of a restored 1979 Triumph Spitfire more than many buyers expect. A 155R13 radial gives the car a blackwall, late-era sports-car look, while a 560-13 bias-ply pushes the presentation toward an older-style appearance, especially when paired with narrow or wide whitewall sidewalls.

That visual difference is often as important as the fitment itself on a restoration-minded car. Construction choice shapes sidewall profile, period feel, and how formal or sporty the Spitfire appears at a glance. Once the appearance direction is set, the remaining decision becomes choosing the specific sidewall style and product that matches the wheels already on the car.

Yes, modifications can affect tire fitment on a 1979 Triumph Spitfire even when the tire size itself is correct. Aftermarket wheels, different wheel widths, suspension changes, altered ride height, or body and fender work can all change the amount of clearance available around a 155R13 or 560-13 tire.

That is why the actual car should be checked before settling on a product, especially when switching between radial and bias-ply construction. Wheel width is particularly important because the available tires do not all share the same approved range. A car that has been changed from stock condition may need closer measurement at steering lock and full suspension movement.

Before driving a 1979 Triumph Spitfire on new tires, inspect the wheels, lug hardware, valve stems, and the basic condition of the suspension and steering components. The tires themselves should be checked for proper seating, correct inflation, and any obvious interference points once the car is back on the ground.

A short, careful test drive is a smart final check. Listen for rubbing, watch for pull or vibration, and recheck air pressure after the first drive cycle. On an older sports car, it also helps to inspect alignment-related wear patterns over the first few outings, since fresh tires can reveal problems that were masked by old or unevenly worn ones.

Collector-car tires on a 1979 Triumph Spitfire should be maintained with regular pressure checks, visual inspections, and attention to age-related condition. Whether the car wears 155R13 radials or 560-13 bias-ply tires, look for cracking, cuts, bulges, uneven tread wear, and signs of slow air loss before the car is driven.

Storage matters just as much as mileage on a low-use British roadster. Keeping the car away from prolonged sunlight, heat, moisture, and ozone sources helps preserve the tires between drives. Even a lightly used set deserves periodic inspection because collector vehicles often age tires out before they wear them out through normal road use.