The 1973 Jaguar XJ12C stands apart as one of Jaguar’s distinctive pillarless grand touring coupes from the XJ era, blending long-hood elegance with the smooth, high-speed character expected of a V12 Jaguar. Tire choice on this car is more about selecting the right interpretation of its original fitment than sorting through multiple primary sizes, because the covered configurations use ER70-15 radial tires on 15-inch rims. That keeps the focus on period-style radial presentation and the details that shape appearance and road manners. For a restoration-minded owner or a driver preparing the car for regular use, correct sizing, wheel confirmation, and overall tire condition matter just as much as brand or sidewall style.
Which Tire Size Is Right for The 1973 Jaguar XJ12C
The 1973 Jaguar XJ12C uses one primary tire size: ER70-15. It is a radial fitment on a 15-inch rim, and that same size carries across both the Base model and the Base w/alloy wheels configuration. That means the main decision is not choosing between multiple factory-type sizes, but selecting the right ER70-15 tire for the car’s appearance, intended use, and wheel setup.
ER70-15 is an alphanumeric radial size, where the letter-based prefix identifies the vintage sizing class, the R indicates radial construction, the 70 refers to the profile family, and the 15 designates the wheel diameter in inches. On a 1973 Jaguar XJ12C, this is the primary fitment and suits the car’s grand touring character more closely than a modern metric code would from a visual standpoint. Buyers looking at this size are usually balancing authentic era presentation with road-use needs rather than trying to decode multiple fitment paths. The key is confirming the car still has the proper 15-inch wheel setup before selecting an ER70-15 tire.
Tire fitment is straightforward across the covered 1973 Jaguar XJ12C sub-models. Both use the same ER70-15 radial size, so sub-model identification matters less for tire size selection than confirming the actual wheels currently on the car.
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1973 Jaguar XJ12C Base
The 1973 Jaguar XJ12C Base uses the ER70-15 radial tire size. Tire selection for this version centers on choosing the right period-style radial in that size and verifying that the car still retains the correct 15-inch wheel arrangement.
The 1973 Jaguar XJ12C Base w/alloy wheels also uses the ER70-15 radial tire size. Since the size remains the same, the practical step is checking wheel condition, width, and overall clearance before replacing older tires or changing brands.
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.
Frequently Asked Questions
Common 1973 Jaguar XJ12C tire questions usually come down to ER70-15 fitment, 15-inch rim compatibility, period-style radial selection, and the checks worth making before putting a collector Jaguar back on the road.
Tire Size & Fitment
What tire size fits a 1973 Jaguar XJ12C?
The 1973 Jaguar XJ12C uses an ER70-15 tire size. This is a radial fitment, and it is the primary size used on the covered configurations of the model, including the Base version and the Base w/alloy wheels version.
That makes tire selection more about choosing the right ER70-15 tire than sorting through multiple original-type sizes. It is still smart to confirm that the car has its correct 15-inch wheels, especially if it has been modified, restored with replacement wheels, or sat unused long enough that the current tire setup may not reflect the intended fitment.
What size rim does a 1973 Jaguar XJ12C use?
The 1973 Jaguar XJ12C uses a 15-inch rim with its ER70-15 tire size. The 15 in the tire code corresponds to wheel diameter, so the tire and wheel must match on that point before anything else is considered.
Wheel diameter is only part of the fitment picture, though. A Jaguar that has seen aftermarket wheel changes or restoration work may also need its wheel width and general clearance checked before replacement tires are chosen. Even when the diameter is correct, an altered wheel setup can affect how an ER70-15 tire sits and behaves on the car.
Do all 1973 Jaguar XJ12C sub-models use the same tire size?
Yes. The covered 1973 Jaguar XJ12C sub-models use the same ER70-15 radial tire size. That includes the Base model and the Base w/alloy wheels configuration, so there is no split in primary tire sizing between those versions.
Because the size stays consistent, the more useful check is whether the car still has the proper wheel setup and enough clearance for the intended tire. On a collector coupe like the XJ12C, wheel replacements, suspension aging, or previous restoration choices can matter more than the sub-model label when it is time to install fresh tires.
Choosing the Right Tire
What should I consider when choosing a ER70-15 tire for a 1973 Jaguar XJ12C?
Start with the correct size and construction. A 1973 Jaguar XJ12C uses an ER70-15 radial tire, so the first priority is staying with that primary fitment and matching it to the car’s 15-inch wheels rather than treating any other vintage-looking size as automatically suitable.
After size is confirmed, the choice becomes one of presentation and use. Some owners want a more restoration-oriented look, while others are focused on dependable road use for touring and events. Wheel width, tire age, overall condition, and how closely the current wheel setup matches the car’s intended configuration all deserve attention before the final selection is made.
How do I choose between the available ER70-15 tires for a 1973 Jaguar XJ12C?
The best way to compare ER70-15 tires for a 1973 Jaguar XJ12C is to keep fitment fixed and look at the details that change from one tire to another. Construction remains radial, so the meaningful differences are usually visual presentation, brand character, and any dimensional or compatibility details tied to the specific tire.
A car headed for judged shows may call for a different visual approach than one used for regular fair-weather driving. It also helps to inspect the wheels before deciding, since a tire that suits the car on paper still needs to match the actual rim setup. Choosing within the correct size is easier when appearance goals and wheel condition are clear first.
What rim-width specifications should I compare when choosing 1973 Jaguar XJ12C tires?
Rim-width specifications matter because an ER70-15 tire needs to be mounted on a wheel that suits the tire’s intended profile and support. Even when the wheel diameter is correct at 15 inches, width still affects how the tire sits on the rim and how it fills the wheel opening.
This is especially worth checking on a Jaguar that may have had wheel changes over the years. A replacement tire should be evaluated against the actual wheel on the car, not just the badge on the fender. Verifying rim width alongside tire size helps avoid mismatched proportions, clearance concerns, and unnecessary guesswork during installation.
Restoration & Appearance
Which tire should I choose for a period-style 1973 Jaguar XJ12C?
For a period-style 1973 Jaguar XJ12C, the starting point is the correct ER70-15 radial size. Keeping the original-type alphanumeric radial format preserves the visual character of the car better than jumping immediately to a modern-looking size code with a different appearance language.
The right choice depends on whether the goal is a restoration-oriented presentation or a road car that still looks appropriate to the era. Exact originality claims should be checked against marque-specific references and restoration documentation, but using the proper ER70-15 fitment keeps the car anchored in the correct visual range for its model year.
Does correct tire fitment matter for a 1973 Jaguar XJ12C restoration?
Yes, correct tire fitment plays a major role in how a 1973 Jaguar XJ12C looks and sits. The right ER70-15 radial size supports the car’s intended stance and helps maintain the balanced appearance that is part of the coupe’s appeal.
Restoration results can be weakened by a tire that looks too modern, too out of proportion, or simply wrong for the wheel. Beyond appearance, proper fitment also helps avoid practical issues during installation and road use. On a restoration-minded Jaguar, tire choice is one of the final details that can either support or distract from the whole car.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1973 Jaguar XJ12C?
Yes. A 1973 Jaguar XJ12C may be intended for ER70-15 tires on 15-inch wheels, but fitment can change if the car has aftermarket wheels, altered ride height, replacement springs, or bodywork that affects tire clearance. Those changes can influence how the tire sits and turns even when the size itself is correct.
That is why the actual wheel and suspension setup should be checked before replacement tires are chosen. A coupe that has been lowered, widened, or fitted with non-original wheels deserves a closer look at steering clearance and wheel dimensions. Correct catalog fitment is the starting point, while the current condition of the car determines the final answer.
What should I inspect before driving a 1973 Jaguar XJ12C on new tires?
Before road use, inspect the wheels, valve stems, lug hardware, and general suspension condition along with the new tires themselves. The tires should be free of shipping damage or mounting issues, and the car’s 15-inch wheels should be in sound condition for an ER70-15 radial installation.
It also helps to check inflation, tread seating, and basic clearance with the steering turned and the suspension loaded normally. A collector Jaguar that has spent long periods parked may have other age-related issues nearby, including worn bushings or brake problems. Tires are only one part of getting the car safely ready for regular driving again.
How should ER70-15 tires on a collector 1973 Jaguar XJ12C be maintained?
ER70-15 tires on a collector 1973 Jaguar XJ12C should be inspected regularly for air loss, sidewall cracking, cuts, bulges, and uneven tread wear. A car that is driven infrequently can age its tires quietly, so appearance alone is not enough to judge whether the tires are still suitable for road use.
Proper inflation and good storage habits go a long way on a low-use coupe. Keeping the car away from prolonged heat, direct sunlight, moisture, and ozone sources helps preserve tire condition between drives. It is also wise to look over the wheels and suspension periodically, since tire wear patterns often reveal problems elsewhere on the car.
