1973 Triumph GT6 Tires

A 1973 Triumph GT6 uses two primary tire sizes: 155R13 in radial construction and 560-13 in bias-ply construction. Both sizes are built for 13-inch wheels, but they reflect two different tire-design eras and two different approaches to how the car can be set up.

The important next step is identifying which construction your GT6 is actually using now and confirming the wheel width before choosing a replacement. A car kept in a restoration-oriented bias-ply format may call for different tire options than one already set up around radial use, even though both remain within the same 13-inch rim diameter.

The 1973 Triumph GT6 uses a 13-inch rim diameter with both of its primary tire sizes. That applies to the 155R13 radial fitment as well as the 560-13 bias-ply fitment, so the wheel diameter does not change when moving between those two tire formats.

Wheel width still matters, because the available tires are not all intended for the same width range. A radial such as 155R13 and a narrower 560-13 bias-ply can place different demands on the wheel, so it is smart to measure the actual rim before ordering and to make sure the tire choice matches the wheel already on the car.

On a 1973 Triumph GT6, 560-13 is a numeric bias-ply tire size. The 5.60 figure is the nominal section width in inches, and the 13 identifies the wheel diameter. It is a traditional sizing format commonly seen on older vehicles and reads very differently from a modern radial size.

That size matters because it points to both the tire’s dimensions and its construction style. When replacing a 560-13, it helps to decide whether the goal is to keep the car in a bias-ply presentation or consider one of the available radial equivalents, then verify wheel width and clearance before changing formats.

For the 1973 Triumph GT6, 560-13 is a bias-ply tire size. It uses the older numeric sizing system and is offered here in classic bias-ply form, while the GT6’s radial fitment is represented separately by the 155R13 size.

That distinction matters because switching between bias-ply and radial is more than a change in labeling. A buyer should match the tire to the car’s current wheel width, intended appearance, and overall setup, especially if the GT6 has been restored, modified, or driven regularly enough that a different construction style would affect the selection process.

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 the named radial alternatives associated with the original 560-13 bias-ply size.

Each equivalent follows a different sizing convention, so the choice is not just about picking any radial with a 13-inch diameter. A recommended rim-width range of 4 to 5 inches applies to these equivalents, and the car’s wheel width, clearance, and overall dimensions should be checked carefully before treating any of them as a practical alternative.

Start by confirming the wheel diameter and width, because the 1973 Triumph GT6 keeps the same 13-inch rim diameter but radial alternatives still depend on proper wheel compatibility. For a 560-13 conversion, the radial-equivalent choices are 155R13, P155/75R13, and P155/70R13, with a recommended rim-width range of 4 to 5 inches tied to those equivalents.

After that, inspect the car itself. Check front and rear clearance, steering travel, suspension condition, and whether the GT6 still has its original-style wheels or any aftermarket changes. A radial equivalent can be a useful option, but the car should be evaluated as it sits rather than assuming every 13-inch radial will behave the same way.

The first decision is whether the car should use the 155R13 radial fitment or the 560-13 bias-ply fitment. That choice shapes everything else, because it affects construction style, appearance, wheel-width compatibility, and the kind of tire series and sidewall treatments available for the GT6.

From there, compare the details that matter to how the car will be used. Radial blackwall options are available from Michelin and Dunlop, while the bias-ply side includes BFGoodrich and Firestone offerings with whitewall treatments. Matching the tire to the car’s wheel width, restoration goals, and road-use expectations usually leads to a better decision than focusing on size alone.

Sidewall style depends on which tire size and construction you choose for a 1973 Triumph GT6. The 155R13 radial products are offered as blackwalls, while the 560-13 bias-ply choices include narrow whitewall and wide whitewall treatments.

That gives the GT6 owner a clear visual choice. A blackwall radial tends to suit a later sports-car presentation, while narrow or wide whitewalls push the car toward a more overt vintage look. Sidewall style should still be chosen only after confirming the correct tire size, construction, and wheel setup, since appearance does not override fitment requirements.

Tires for the 1973 Triumph GT6 are available from Michelin, Dunlop, BFGoodrich, and Firestone. Michelin and Dunlop cover the radial 155R13 fitment, while BFGoodrich and Firestone supply 560-13 bias-ply options in classic-style series.

Brand matters mostly as part of a larger comparison rather than as a standalone answer. Once the correct size and construction are settled, it makes sense to compare the available series, sidewall treatments, rim-width specifications, load figures where given, and the overall look you want the GT6 to carry on the road or at shows.

For a period-style 1973 Triumph GT6, the 560-13 bias-ply fitment is the natural starting point because it preserves the traditional size format and construction associated with older tire presentation. Available options include classic bias-ply series from BFGoodrich and Firestone, with narrow whitewall and wide whitewall treatments.

That does not automatically make every 560-13 the right choice for every restoration. Some owners want a more restrained look, while others want a more decorative whitewall treatment, and wheel width still needs to match the tire selected. When exact originality matters, marque references and vehicle-specific historical documentation are still worth consulting before finalizing the appearance.

On a restored 1973 Triumph GT6, tire construction changes the visual character as much as the driving setup. A 560-13 bias-ply gives the car a more traditional vintage presentation, especially in whitewall form, while a 155R13 radial presents the GT6 with a later, cleaner blackwall look.

That difference is especially noticeable on a compact sports coupe where the tire and wheel package is very visible. Choosing between bias-ply and radial should therefore match the restoration goal, not just the dimensions. A car aimed at period-style display may call for a different look than one restored for regular road miles and modern convenience.

Yes. Even though the 1973 Triumph GT6 uses 13-inch tire fitments, modifications can change what actually works on the car. Aftermarket wheels, altered wheel width, suspension changes, ride-height adjustments, or bodywork differences can all affect whether a chosen tire has the clearance and support it needs.

That is especially important when moving between the 560-13 bias-ply format and a radial such as 155R13 or one of the radial equivalents. The smart approach is to inspect the GT6 as it currently sits, measure the actual wheels, and check steering and fender clearance instead of assuming the car still matches an untouched factory-era setup.

Before driving a 1973 Triumph GT6 on new tires, inspect the wheels for correct diameter and width, make sure the tires are seated properly, and confirm there is no interference at full steering lock or through suspension movement. It also helps to check valve stems, overall tire pressure, and whether the car has any obvious alignment or suspension issues.

A collector car that sees limited mileage deserves an extra look beyond the tires alone. Check for loose suspension components, worn bushings, and signs that the previous tires rubbed or wore unevenly. A careful inspection after the first short drive is worthwhile too, since that gives you a chance to catch clearance or pressure issues early.

Tires on a collector 1973 Triumph GT6 should be inspected regularly for air loss, tread wear, sidewall cracking, cuts, and bulges, even if the car is driven only occasionally. Low annual mileage does not stop tires from aging, and a car that spends long periods parked can develop issues that are easy to miss at a glance.

Storage conditions matter just as much as mileage. Keeping the GT6 away from prolonged sunlight, moisture, high heat, and ozone sources helps preserve the tires, whether the car wears 155R13 radials or 560-13 bias-ply tires. Before any longer drive, confirm pressures, look over the tread and sidewalls again, and make sure the spare is roadworthy as well.