The 1978 Triumph TR7 sits squarely in the late-1970s British sports-car world, combining wedge-shaped styling with a very different character from the earlier Triumph roadsters that came before it. For many owners, that means tire choice is part appearance decision and part road-use decision. The 1978 Triumph TR7 uses 13-inch radial fitments, with both 185/70R13 and 185R13 associated with the model. That opens the door to choices ranging from traditional blackwall European-style radials to more distinctive period-style looks such as redline or wide whitewall in 185/70R13. The key is matching the tire to the car’s actual wheel setup and the kind of restoration or driving experience you want.
Which Tire Size Is Right for The 1978 Triumph TR7
The 1978 Triumph TR7 is associated with two primary radial tire sizes, and both use a 13-inch rim. Because the TR7 Base can use either 185/70R13 or 185R13, the real decision is not simply construction, but which sizing format, profile, and tire style best suit the car’s wheels, appearance, and intended road use.
A 185/70R13 tire uses a 185-millimeter nominal section width, a 70-series aspect ratio, radial construction, and a 13-inch rim diameter. On a 1978 Triumph TR7, this size represents a lower-profile modern metric radial format while staying within the correct 13-inch wheel family. Available choices include BFGoodrich, Avon, Dunlop, Michelin, and Vredestein, with blackwall, redline, and wide whitewall sidewall treatments depending on the tire series. This size makes sense for owners comparing a broader mix of touring, sporting, and period-style presentation options on the TR7.
A 185R13 tire uses a 185-millimeter nominal section width, radial construction, and a 13-inch rim, with no aspect ratio stated in the size itself. That Euro-metric format is commonly associated with a more traditional radial sizing convention than a modern 70-series metric tire. In this size, the available TR7 option is the Michelin XAS-FF in a blackwall presentation, giving the buyer a distinctly classic radial choice. This size is worth considering when the goal is a more traditional European tire format for a 13-inch TR7 wheel setup.
Tire fitment is straightforward here because the covered 1978 Triumph TR7 sub-model shares the same two radial size paths. Checking the exact sub-model still matters, but the main decision is choosing between the 185/70R13 metric radial format and the 185R13 Euro-metric radial format.
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1978 Triumph TR7 Base
The 1978 Triumph TR7 Base is associated with both 185/70R13 and 185R13 radial tire sizes on 13-inch rims. That gives the owner a choice between a more modern metric radial format and a more traditional Euro-metric radial, along with different brand, sidewall, and tire-series options depending on the size selected.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1978 Triumph TR7 Tires for Sale
Available 1978 Triumph TR7 tire choices center on 185/70R13 and 185R13 radials from BFGoodrich, Avon, Dunlop, Michelin, and Vredestein. Buyers can compare blackwall, redline, and wide whitewall appearances, along with different tire series and rim-width ranges within the 13-inch fitment family.
Common 1978 Triumph TR7 tire questions usually come down to choosing between 185/70R13 and 185R13, understanding 13-inch rim fitment, comparing radial styles, and checking wheel, suspension, and tire condition before regular road use.
Tire Size & Fitment
What tire size fits a 1978 Triumph TR7?
The 1978 Triumph TR7 is associated with two radial tire sizes: 185/70R13 and 185R13. Both sizes use a 13-inch rim, and both are tied to the TR7 Base, so the fitment question is less about sub-model differences and more about which of those two radial formats matches the car’s current wheel and tire setup.
A TR7 that still has its original-style 13-inch wheels may be a candidate for either size, but the exact tire choice should be checked against wheel width, overall tire proportions, and clearance around the body and suspension. Looking at the tires already on the car and confirming the wheel dimensions is the best starting point before choosing between the two formats.
What size rim does a 1978 Triumph TR7 use?
The 1978 Triumph TR7 uses a 13-inch rim diameter with both of its associated tire sizes. That applies whether the car is running 185/70R13 or 185R13, so the wheel diameter stays consistent even though the tire size format changes between a modern metric radial and a Euro-metric radial.
Rim diameter is only part of the fitment picture, so it is still important to confirm wheel width before selecting a tire. Several 185/70R13 products include rim-width guidance, and that can influence which tire is the better match for the wheels currently on the car. A 13-inch wheel is required, but width and overall setup still deserve a careful check.
What does 185R13 mean on a 1978 Triumph TR7?
On a 1978 Triumph TR7, 185R13 is a Euro-metric radial size. The 185 refers to nominal section width in millimeters, the R indicates radial construction, and the 13 is the rim diameter in inches. Unlike a size such as 185/70R13, the aspect ratio is not written directly into the size code.
That matters because 185R13 and 185/70R13 are not simply different ways of writing the same thing. They are different radial sizing conventions, and they can lead a buyer toward different tire series and a different visual presentation on the car. Checking the existing wheels and comparing the current tire setup helps determine which format better suits the TR7.
Choosing the Right Tire
What should I consider when choosing a 185/70R13 tire for a 1978 Triumph TR7?
Start with the basics: a 185/70R13 for a 1978 Triumph TR7 should match the car’s 13-inch wheel diameter and should also suit the wheel width. Beyond fitment, this size gives access to several distinct tire series and sidewall presentations, including blackwall, redline, and wide whitewall options depending on the brand and product line.
The best way to narrow the choice is to decide whether the car is aimed at traditional appearance, sport-oriented visual character, or general collector-car road use. Comparing rim-width guidance, load figures where shown, and the overall look of the sidewall can help separate similar-looking options without treating every 185/70R13 radial as the same tire.
What sidewall styles are available for 1978 Triumph TR7 tires?
Sidewall choices for the 1978 Triumph TR7 include blackwall, redline, and wide whitewall, depending on the tire size and product selected. Most of the available radial choices are blackwall, while 185/70R13 also opens the door to BFGoodrich Silvertown Radial options with redline or 2-inch whitewall styling.
That sidewall decision can change the car’s personality as much as the tire brand does. A blackwall tends to keep the look more restrained and European, while a redline or wide whitewall creates a more customized period-style presentation. It is worth checking that the appearance matches the rest of the car, especially if the TR7 has been restored, modified, or personalized.
What brands offer tires for the 1978 Triumph TR7?
Tires for the 1978 Triumph TR7 are available from BFGoodrich, Avon, Dunlop, Michelin, and Vredestein. Most of that variety appears in 185/70R13, while 185R13 is represented by Michelin. The available tire series include Silvertown Radial, CR6ZZ, SP Sport Aquajet, Sport Classic, XDX-B, Sprint Classic, and XAS-FF.
Brand choice should be considered alongside tire size, sidewall style, and intended use rather than as a shortcut by itself. Some owners will focus on a traditional European blackwall look, while others may want a more customized period-style appearance. Once the size is confirmed, comparing the series character and wheel-width compatibility becomes more useful than brand name alone.
Restoration & Appearance
Which tire should I choose for a period-style 1978 Triumph TR7?
A period-style 1978 Triumph TR7 tire choice usually starts with deciding whether the car should wear a traditional European-looking blackwall radial or a more personalized vintage appearance. Both 185/70R13 and 185R13 belong to the TR7 fitment picture, and each points to a slightly different style of radial presentation on a 13-inch wheel.
A Michelin XAS-FF in 185R13 leans toward a classic Euro-radial character, while 185/70R13 opens more visual variety through blackwall, redline, and wide whitewall offerings. Owners pursuing exact originality should compare any final choice with marque-club guidance, period photos, or restoration records, since period-style appearance and exact factory delivery are not always the same thing.
How does tire construction affect the appearance of a restored 1978 Triumph TR7?
On the 1978 Triumph TR7, construction is simpler than it is on many older collector cars because the associated primary fitments are both radial. That means the appearance difference comes less from bias-ply versus radial and more from the tire’s sizing format, profile, sidewall treatment, and the character of the specific tire series chosen.
A 185R13 Euro-metric radial can give the car a more traditional European presentation, while 185/70R13 brings a more modern written size format and a broader range of visible style choices. Details such as blackwall, redline, or wide whitewall can noticeably change the finished look, so tire selection should be considered part of the restoration’s visual plan rather than an afterthought.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1978 Triumph TR7?
Yes, modifications can affect tire fitment on a 1978 Triumph TR7 even when the tire size itself is correct. Aftermarket wheels, changes in wheel width, suspension alterations, ride-height changes, or body modifications can all influence whether 185/70R13 or 185R13 remains the better choice for the car’s current configuration.
The safest approach is to confirm the actual wheel diameter and width on the car before selecting tires, then check steering travel and clearance at the fenders and suspension. A TR7 that has been lowered or fitted with different wheels may need closer attention to overall proportions and available space than a car that still has its original-style setup.
What should I inspect before driving a 1978 Triumph TR7 on new tires?
Before putting a 1978 Triumph TR7 back on the road with new tires, inspect the wheels for damage or corrosion and make sure the tire size matches the 13-inch rim setup. The car should also be checked for alignment condition, suspension wear, and any signs that old tires were rubbing or wearing unevenly before the replacement.
After installation, keep an eye on inflation pressure, bead seating, and early tread wear during the first miles. It also helps to confirm that the spare, lug hardware, and jack are still appropriate for the wheel and tire combination now on the car. Small setup issues tend to show up quickly on a light sports car, so early inspection is worthwhile.
How should tires on a collector 1978 Triumph TR7 be maintained?
Tires on a collector 1978 Triumph TR7 should be maintained with regular pressure checks, periodic visual inspection, and attention to age-related deterioration as much as tread depth. Low-mileage collector cars often spend long periods parked, so sidewall cracking, flat spotting, air loss, and general rubber aging deserve just as much attention as wear from normal driving.
Storage conditions matter too. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources can help preserve the tires between drives. Moving the car occasionally and inspecting the tread and sidewalls before road use is a sensible routine, especially on a TR7 that is driven seasonally or only brought out for shows and weekend trips.
