1968 Triumph Sports Six Tires

The 1968 Triumph Sports Six uses two primary tire sizes: 560-13 in bias-ply construction and 155R13 in radial construction. Both sizes are built for 13-inch rims, so the main difference is the tire format and construction rather than wheel diameter.

That means the first step is confirming whether the car is currently set up for bias-ply or radial tires. A Sports Six that has been restored, modified, or converted over time may not still be using the same wheel-width range it left with, so the tire choice should be matched to the actual wheels on the car as well as the intended appearance and road use.

The 1968 Triumph Sports Six uses a 13-inch rim with both of its applicable tire sizes. The 560-13 bias-ply and the 155R13 radial are both built around that same 13-inch wheel diameter, which keeps the basic wheel-size question simple.

Even with the same rim diameter, wheel width still matters when choosing between available tires. Some 560-13 bias-ply products are intended for narrower wheels, while 155R13 radial products can cover a broader width range, so the buyer should confirm both diameter and wheel width before selecting a tire or changing construction.

Yes. The 1968 Triumph Sports Six Base uses the same two fitment paths as the model core: 560-13 in bias-ply construction and 155R13 in radial construction. There is no separate sub-model tire size split to sort through here.

That keeps selection focused on construction and presentation rather than trim-specific fitment. The practical decision is whether the car should stay with a traditional bias-ply look, move to a radial setup, or continue using whichever construction already matches its wheels, suspension condition, and restoration direction.

560-13 is a bias-ply tire size for the 1968 Triumph Sports Six. It uses the older numeric sizing format common on many vintage vehicles, and the available products in this size for the Sports Six are bias-ply tires rather than radials.

That makes 560-13 the traditional choice for owners who want an older-style construction and a more vintage visual presentation. It is still important to check wheel width before selecting a specific product, because the available 560-13 bias-ply tires do not all share the same rim-width range or sidewall treatment.

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. No bias-look radial equivalent is paired with 560-13 here.

Those sizes provide different radial-format alternatives while keeping the conversation in the same general fitment family. A recommended rim-width range of 4 to 5 inches applies to the equivalent comparison, and any switch from 560-13 should be checked against the car's wheel width, tire clearance, and overall setup instead of assuming automatic interchangeability.

Before converting a 1968 Triumph Sports Six from 560-13 bias-ply tires to a radial alternative, confirm the wheel diameter and wheel width first. The radial-equivalent choices tied to 560-13 include 155R13, P155/75R13, and P155/70R13, but each should still be evaluated against the actual wheel and vehicle setup.

It also helps to inspect steering clearance, fender clearance, and overall suspension condition before making the change. A collector car may have replacement wheels, suspension wear, or previous modifications that affect fitment, so the conversion decision should balance appearance goals, road use, and compatibility with the car as it sits today.

Start with the correct size and construction for the way the 1968 Triumph Sports Six is set up. The main fitment paths are 560-13 in bias-ply form and 155R13 in radial form, so the real choice is between vintage-style construction and a radial-format alternative on the same 13-inch rim diameter.

From there, compare wheel-width requirements, sidewall appearance, brand, tire series, and any load or weight specifications that matter to your intended use. A Sports Six aimed at show presentation may call for a different tire character than one meant for regular road driving, even when both remain within the correct size family.

The available sidewall styles for the 1968 Triumph Sports Six include blackwall in 155R13 radial products, along with narrow whitewall and wide whitewall treatments in 560-13 bias-ply products. That gives the car two very different visual directions depending on the tire size and construction chosen.

Blackwall radials suit a restrained European sports-car look, while the whitewall bias-ply options create a more overtly vintage presentation. The sidewall choice should be considered alongside construction, wheel width, and restoration goals, since the appearance can change the character of the car just as much as the sizing format does.

Michelin and Dunlop offer radial choices for the 1968 Triumph Sports Six in the 155R13 range, while BFGoodrich and Firestone cover the 560-13 bias-ply side. Those brands also span different tire series, including Michelin XAS-FF, SP Sport Aquajet, Silvertown Classic Bias Ply, and Firestone Classic Bias Ply.

Brand should be only one part of the decision. The more useful comparison is how each option matches the car's existing construction type, wheel-width needs, and preferred appearance, since a blackwall radial and a wide whitewall bias-ply can both be appropriate choices for very different Sports Six goals.

A period-style 1968 Triumph Sports Six usually starts with deciding whether the car should present as a traditional bias-ply restoration or as a classic sports car wearing an early-style radial format. The 560-13 bias-ply size supports that older construction path, while 155R13 keeps the car in a classic Euro-metric radial range.

The best choice depends on how strictly the car is being restored and how it will be used. When exact originality matters, marque references and vehicle-specific historical documentation are worth consulting, but for many owners the decision comes down to whether the visual target is vintage bias-ply character or classic radial understatement.

Tire construction changes the visual character of a restored 1968 Triumph Sports Six more than many buyers expect. A 560-13 bias-ply brings a distinctly vintage presentation, especially with narrow whitewall or wide whitewall sidewalls, while a 155R13 radial in blackwall form creates a more restrained and European-looking finish.

That difference matters because tires sit at the edge of every body line and wheel opening. A restoration-oriented buyer should consider the wheel style, trim level of finish, and intended presentation of the whole car before choosing, rather than selecting on size alone and discovering later that the overall look has shifted.

Yes, modifications can affect tire fitment on a 1968 Triumph Sports Six even when the nominal tire size remains within the usual 560-13 or 155R13 range. Aftermarket wheels, different wheel widths, altered ride height, or suspension changes can all influence how much room the tire has once the car is loaded and steering is turned.

That is especially important on a small British sports car where clearances can be tighter than they appear at rest. A modified car should be checked for wheel width, inner and outer clearance, and steering travel before choosing a replacement tire, particularly when moving between bias-ply and radial construction.

Before driving a 1968 Triumph Sports Six on new tires, inspect the wheels for correct diameter and condition, then confirm that the chosen tire matches the wheel width and seats properly. It also makes sense to look over steering and suspension components so the new tires are not being asked to work around worn parts.

A road-ready check should also include inflation pressure, valve condition, and a close look for any interference at full steering lock or over suspension movement. On a collector car that may sit for long periods, it is smart to recheck for air loss and verify that nothing has shifted after the first short drive.

Tires on a collector 1968 Triumph Sports Six should be maintained with regular pressure checks, visual inspections, and close attention to age and condition. Low-use cars can develop problems even when tread wear looks minimal, so sidewall cracking, bulges, cuts, and recurring air loss deserve more attention than mileage alone.

Storage conditions matter as much as road use on a vintage car. Keeping the Sports Six away from prolonged sunlight, excess heat, moisture, and ozone sources helps protect the tires, and periodic inspection before each outing is a good habit whether the car is running blackwall radials or whitewall bias-ply tires.