1968 Triumph GT6 Tires

A 1968 Triumph GT6 is associated with two tire sizes: 560-13 in bias-ply construction and 155R13 in radial construction. Both sizes use a 13-inch rim, so the primary fitment question is not wheel diameter but which construction and size format best match the car’s current setup and intended use.

That means the next step is confirming whether the GT6 is being kept in a more traditional bias-ply configuration or whether a radial-format tire is the better match. Wheel width, tire clearance, and the car’s existing stance should all be checked before changing from one construction style to the other.

The 1968 Triumph GT6 uses a 13-inch rim with both of its associated tire sizes. That includes the 560-13 bias-ply fitment and the 155R13 radial fitment, so rim diameter stays consistent even though the tire construction and sizing language change.

Rim diameter is only part of the picture, however. Actual wheel width still matters, especially because the available radial and bias-ply products are built around different rim-width ranges. Checking the wheel itself before selecting a tire helps avoid pairing the correct diameter with the wrong width or construction type.

On a 1968 Triumph GT6, 560-13 is a numeric bias-ply tire size. The 560 portion represents an approximate 5.60-inch nominal section width, and the 13 identifies the wheel diameter in inches. It is a traditional sizing format that predates modern metric radial naming conventions.

That matters because a 560-13 tire is selected differently than a 155R13 radial, even though both are tied to the same 13-inch rim diameter. Buyers comparing the two should look beyond the numbers and consider construction, wheel width, sidewall style, and how closely they want the tire to reflect a period-style presentation.

For the 1968 Triumph GT6, 560-13 is a bias-ply tire size. It uses a vintage numeric sizing format and appears in classic bias-ply product lines from BFGoodrich and Firestone, including whitewall options that emphasize a traditional appearance.

That makes 560-13 the fitment to study closely when preserving an older visual character is part of the goal. Buyers considering a shift away from bias-ply should compare wheel-width needs, overall size relationship, and suspension clearance rather than assuming that any 13-inch radial is automatically suitable.

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

Each one should be treated as an alternative to evaluate rather than an automatic replacement. The associated rim-width range is 4 to 5 inches, and the owner should still confirm wheel width, overall tire dimensions, and fender or suspension clearance before converting a 1968 Triumph GT6 from bias-ply to radial construction.

A 1968 Triumph GT6 can be approached either way because it is associated with both 560-13 bias-ply and 155R13 radial fitments. The better choice depends on what matters most for the car: a more traditional period-style presentation or a radial-format setup within the same basic 13-inch fitment family.

Bias-ply and radial tires can change the car’s look and how it responds on the road, so the decision should be made deliberately. A careful check of wheel width, tire clearance, and the condition of steering and suspension components helps ensure the selected construction suits the GT6’s current configuration.

Start with the correct fitment family for the car: 560-13 if a bias-ply presentation is the goal, or 155R13 if a radial-format setup is preferred. From there, compare wheel-width compatibility, construction type, sidewall style, and the character of the available tire series rather than focusing on size code alone.

A GT6 used for restoration-minded presentation may call for a very different tire than one prepared for regular road driving. It also helps to confirm the actual wheels on the car, since an older Triumph may no longer be running its original-width rims, and that can influence which products make the most sense.

Sidewall choices for the 1968 Triumph GT6 include blackwall, narrow whitewall, and wide whitewall styles. The blackwall options appear with the 155R13 radial choices, while the 560-13 bias-ply choices include both narrow whitewall and wide whitewall versions in classic tire lines.

That variety lets the tire contribute strongly to the car’s visual tone. A blackwall radial gives the GT6 a restrained sporting look, while whitewall bias-ply tires move the car toward a more vintage presentation. The best choice comes from matching sidewall style to the overall appearance you want rather than choosing by color alone.

Tires for the 1968 Triumph GT6 are available from Michelin, Dunlop, BFGoodrich, and Firestone. Michelin and Dunlop cover the 155R13 radial side of the fitment, while BFGoodrich and Firestone offer 560-13 bias-ply choices with traditional whitewall treatments.

That brand spread is useful because it lines up with different priorities rather than simply giving multiple names in the same niche. Some buyers will focus on European-style radial series, while others will be comparing bias-ply whitewall presentation and rim-width compatibility within the 560-13 range.

For a period-style 1968 Triumph GT6, the 560-13 bias-ply size is the most natural starting point because it preserves the vintage numeric format and opens access to classic bias-ply tire lines. That route suits owners who want the tire itself to reinforce the car’s late-1960s visual character.

Appearance decisions still need to be balanced against the actual wheel setup and how the car will be used. If historical accuracy is especially important, marque references and vehicle-specific restoration guidance can help narrow down the most appropriate sidewall presentation without assuming every tire sold in the size matches the car’s original delivery.

Tire construction changes the visual impression of a restored 1968 Triumph GT6 more than many buyers expect. A 560-13 bias-ply gives the car a more traditional vintage look, especially when paired with narrow whitewall or wide whitewall styling, while a 155R13 radial blackwall creates a more understated sporting presentation.

That visual difference is one reason construction should be chosen early in a restoration plan. The tire needs to work with the wheel, stance, and trim treatment already on the car. Picking by appearance alone can lead to a mismatch, so the final choice should balance fitment, intended use, and the era-specific look being pursued.

Yes, modifications can affect tire fitment on a 1968 Triumph GT6 even when the tire size itself is correct. Aftermarket wheels, different wheel widths, altered suspension height, and body or fender changes can all influence whether a 560-13 or 155R13 tire has the clearance it needs.

That is why an older GT6 should be measured as it sits today rather than treated as completely stock by default. Tire diameter is only one part of fitment. Wheel width, steering clearance, and how close the tire runs to suspension components all deserve a careful look before final tire selection.

Before driving a 1968 Triumph GT6 on new tires, inspect the wheels for correct diameter and width, then confirm proper mounting and inflation. The car should also be checked for obvious alignment issues, loose steering components, suspension wear, and any clearance points that could contact the tire during turning or suspension movement.

Collector cars often spend long periods parked, so roadworthiness depends on more than fresh rubber alone. It is smart to look over brake function, wheel fastener condition, and signs of rubbing after the first short drive. A careful initial inspection helps the new tires perform as intended without introducing avoidable fitment problems.

Tires on a collector 1968 Triumph GT6 should be maintained with regular pressure checks, visual inspections, and attention to age-related condition even if tread wear is minimal. Sidewall cracking, bulges, cuts, uneven wear, and gradual air loss all matter on low-mileage cars that may sit for extended periods.

Storage conditions also make a difference. Keeping the GT6 away from prolonged sunlight, excess heat, moisture, and ozone sources helps protect both bias-ply and radial tires. Occasional inspection of the spare, the valve stems, and the wheel condition rounds out a maintenance routine that suits a lightly used collector car.