1978 Triumph Spitfire Tires

The 1978 Triumph Spitfire uses two primary tire sizes: 155R13 in radial construction and 560-13 in bias-ply construction. Both sizes are associated with the Spitfire Base and both are designed for 13-inch rims, so the fitment question is less about wheel diameter and more about choosing the construction and appearance that suit the car.

That means the next step is confirming the wheel setup actually on the car. Many older British sports cars have seen wheel changes over time, and rim width matters as much as rim diameter when comparing a radial to a bias-ply option. It also helps to decide whether the goal is a more traditional period-style presentation or a radial setup for regular road use.

The supported tire sizes for a 1978 Triumph Spitfire both use a 13-inch rim diameter. The radial 155R13 and the bias-ply 560-13 are both tied to that same wheel diameter, which simplifies the basic fitment question compared with vehicles that used different wheel sizes across trims or packages.

Diameter is only part of the picture, though. Product specifications show different rim-width ranges depending on the tire and construction, so an owner should confirm the actual wheel width before making a final selection. That becomes especially important when switching between bias-ply and radial tires, or when the car has aftermarket wheels instead of its original-style rims.

Yes. The 1978 Triumph Spitfire Base is covered by the same two primary sizes used on this page: 155R13 as a radial and 560-13 as a bias-ply. Rather than separating the Base into a different wheel diameter or a unique tire package, the fitment choice centers on which of those two constructions best matches the car’s intended use and appearance.

That makes selection more straightforward, but it does not remove the need to inspect the car itself. A Spitfire that has been modified with different wheels, suspension changes, or a non-stock stance may need extra clearance checks. On an unmodified car, the practical decision usually comes down to radial versus bias-ply, sidewall style, and matching the tire to the wheel width.

560-13 is a bias-ply tire size for the 1978 Triumph Spitfire. It uses the older numeric bias-ply sizing system, where the leading number represents a nominal section-width class and the final number identifies the 13-inch rim diameter. On this Spitfire, 560-13 serves as the traditional-construction alternative to the radial 155R13 size.

That distinction matters because a bias-ply tire changes both presentation and setup choices. The available 560-13 options include narrow whitewall and wide whitewall styles, which suit a more vintage look than the blackwall radial offerings. Anyone moving away from 560-13 should confirm wheel width, compare the tire’s dimensions carefully, and check steering and body clearance before making the change.

Radial equivalents for 560-13 include 155R13 as the 80-series metric radial option, P155/75R13 as the P-metric 75-series radial option, and P155/70R13 as the P-metric 70-series radial option. These are equivalent-size comparisons for the Spitfire’s 560-13 bias-ply fitment rather than additional primary factory-style size listings.

A recommended rim-width range of 4 to 5 inches accompanies those equivalents, which gives a useful starting point when evaluating a conversion. Even so, equivalent does not mean automatic interchangeability. Wheel width, installed tire dimensions, suspension condition, and fender or steering clearance should all be reviewed before choosing one of these radial alternatives for a 1978 Triumph Spitfire.

A 1978 Triumph Spitfire can be set up with either its 155R13 radial fitment or its 560-13 bias-ply fitment, so the choice depends on how the car is being used and presented. The radial route stays within the covered 155R13 fitment, while the bias-ply route keeps the older numeric size and opens the door to more traditional whitewall styling.

Owners focused on a vintage visual character may lean toward the bias-ply size, while those planning regular road driving may prefer to stay within the radial-style fitment. The wheel setup should guide the final choice, especially if the car no longer has original-style rims. Construction changes also deserve a full check of wheel width, tire clearance, and overall vehicle condition before installation.

Start with the two supported sizes and what they represent. A 1978 Triumph Spitfire can use either a 155R13 radial or a 560-13 bias-ply tire, both on 13-inch rims. From there, the main decision is whether the car needs a radial setup for later-period road use or a bias-ply tire for a more traditional look.

After size and construction, compare sidewall treatment, brand, tire series, and wheel-width compatibility. The available products range from blackwall radials to narrow whitewall and wide whitewall bias-ply designs, so appearance can change significantly even within the correct fitment. It also helps to consider how often the car is driven and whether the current wheels still match the intended tire’s width requirements.

The available sidewall styles for the 1978 Triumph Spitfire include blackwall, narrow whitewall, and wide whitewall. Blackwall choices appear in the 155R13 radial fitment, while narrow whitewall and wide whitewall treatments appear in the 560-13 bias-ply fitment. That creates a clear difference in visual character between the two size and construction paths.

Sidewall style should be matched to the way the Spitfire is being presented rather than chosen in isolation. A blackwall radial tends to suit a more understated sports-car look, while whitewall bias-ply tires create a more traditional period-style appearance. The important thing is keeping the selection within the correct supported size and making sure the wheel width matches the specific tire chosen.

Tires for the 1978 Triumph Spitfire are available from Michelin, Dunlop, BFGoodrich, and Firestone. Michelin and Dunlop cover the 155R13 radial fitment in blackwall form, while BFGoodrich and Firestone offer 560-13 bias-ply choices with whitewall styling. Those brand differences line up with the broader decision between a radial sports-car presentation and a more traditional bias-ply look.

Brand alone should not decide the purchase. It makes more sense to narrow the choice by size, construction, and sidewall treatment first, then compare the tire series and wheel-width requirements within that group. That approach keeps the focus on the Spitfire’s actual fitment needs and helps avoid choosing a tire that looks right but does not match the car’s intended setup.

For a period-style 1978 Triumph Spitfire, the right starting point depends on which era of appearance the owner wants to emphasize. The car can be fitted with either a 155R13 radial or a 560-13 bias-ply tire, so both a later-style blackwall radial presentation and a more traditional bias-ply look are represented within the supported fitment range.

A restoration-oriented choice should consider more than size alone. Sidewall treatment changes the car’s visual balance, and the available 560-13 tires include both narrow whitewall and wide whitewall versions. If exact originality matters, period photos, marque-club guidance, and vehicle-specific records are the best way to confirm what appearance is appropriate before settling on a particular construction or sidewall style.

Tire construction changes the overall presentation of a restored 1978 Triumph Spitfire because the covered fitments split between a radial 155R13 and a bias-ply 560-13. The radial options are blackwall vintage-sport tires, while the bias-ply options bring a more traditional look through narrow whitewall and wide whitewall treatments. That makes construction part of the visual decision, not just a technical one.

A Spitfire restored with an emphasis on classic sports-car road use may look right on a blackwall radial, while a more nostalgic presentation may lean toward the bias-ply size. The important point is to treat appearance and fitment together. A tire that complements the car visually still needs to suit the wheel width and the way the vehicle will actually be driven.

Yes, modifications can affect tire fitment on a 1978 Triumph Spitfire even when the chosen tire is one of the supported sizes. Changes such as aftermarket wheels, altered wheel width, suspension lowering, replacement springs, or bodywork differences can all influence clearance. That matters with either the 155R13 radial or the 560-13 bias-ply fitment because both rely on a 13-inch wheel but not necessarily the same wheel width.

A modified car should be checked at full steering lock and through normal suspension travel before a final tire choice is made. Owners should also confirm actual wheel dimensions rather than assuming the car still has its original-style setup. On a small sports car like the Spitfire, even modest changes in wheel or suspension setup can alter fender and steering clearance enough to matter.

Before driving a 1978 Triumph Spitfire on new tires, inspect the wheels, valve stems, and overall mounting condition first. Then check inflation pressure, sidewall condition, tread seating, and any signs of rubbing or contact around the fenders and steering components. On a car with 155R13 or 560-13 tires, a careful visual check after installation helps confirm that the tire and wheel combination is behaving normally.

A short, low-speed shakedown drive is a smart next step, followed by another inspection for air loss, unusual marks, or clearance issues. Older sports cars also deserve attention to suspension bushings, steering parts, and wheel bearings before regular road use. New tires can only perform as intended when the rest of the chassis is in sound condition and the wheels are properly matched.

Collector-car tires on a 1978 Triumph Spitfire should be maintained with regular pressure checks, routine visual inspection, and careful storage habits. Whether the car wears 155R13 radials or 560-13 bias-ply tires, look for cracking, bulges, cuts, uneven wear, and any unexplained air loss. A low-mileage car can still develop tire issues simply from age, storage conditions, or long periods of inactivity.

Storage matters almost as much as driving mileage on a lightly used Spitfire. Keeping the car away from prolonged sunlight, heat, moisture, and ozone sources helps protect the rubber over time. It also helps to move the vehicle periodically and inspect the tires before every road outing, especially if the car spends long stretches parked between drives or show appearances.