1978 Jaguar XJS Tires

A 1978 Jaguar XJS uses two radial tire sizes: 205/70R15 and ER70-15. Both are 15-inch fitments, and both appear across the covered XJS sub-models, including the Base and Base w/alloy wheels. The difference is mainly the sizing convention and visual presentation rather than a change in basic wheel diameter.

Choosing between them starts with confirming the actual wheels on the car and deciding whether a modern metric radial or a vintage alphanumeric radial better suits the car’s appearance and intended use. If the car has been modified over the years, wheel width and clearance should be checked before settling on one size format.

The covered tire fitments for a 1978 Jaguar XJS use a 15-inch rim diameter. That applies to both 205/70R15 and ER70-15, so the wheel diameter remains consistent even though the tire sizes are written in two different radial sizing formats.

Rim diameter is only part of the picture, especially on a collector grand touring car. Wheel width also matters when comparing tire choices, since some 205/70R15 products are intended for different rim-width ranges. A quick wheel check before purchase helps avoid confusion between a correct 15-inch diameter and a tire that may not suit the actual wheel width on the car.

Yes. The covered 1978 Jaguar XJS sub-models share the same two radial fitment choices, 205/70R15 and ER70-15. That includes both the Base model and the Base w/alloy wheels, so there is no separate tire-size split between those two sub-models in this fitment range.

Even with shared fitment, the car should still be checked for changes made over time. Alloy wheels, replacement wheels, and older restorations can alter actual wheel width or tire preference. Once the wheel setup is confirmed, the choice usually comes down to whether a modern metric radial or a period-style alphanumeric radial better matches the car.

Start with the basics: correct 15-inch fitment, radial construction, and compatibility with the car’s actual wheel width. From there, 205/70R15 gives the 1978 Jaguar XJS a broad range of choices, including blackwall, narrow whitewall, and wide whitewall designs across several tire series and brands.

The right pick depends on how the car is used and presented. A blackwall often suits a more performance-oriented or European touring look, while whitewall styles lean more restoration-oriented or personal in taste. It also helps to compare rim-width recommendations, load figures where stated, and whether the car still wears its original wheel setup.

1978 Jaguar XJS tires are available in blackwall, narrow whitewall, and wide whitewall styles within the covered fitment range. Those options appear mainly in 205/70R15, giving owners a meaningful appearance choice without leaving the proper 15-inch radial category used on the car.

Sidewall style changes the character of the car visually, so it is worth choosing with intention rather than treating it as a minor detail. A blackwall keeps the look more understated and sporting, while narrow and wide whitewalls create a more traditional presentation. Owners pursuing exact originality should confirm period references for their particular car before selecting a whitewall width.

The 1978 Jaguar XJS fitment range includes tires from Maxxis, Michelin, Avon, American Classic, Coker Classic, Dunlop, Tornel, and Travelstar. Most of that variety appears in 205/70R15, giving buyers a wider field of brands and tire-series character within the same basic radial size.

Brand choice should be treated as one part of a larger fitment decision rather than the only factor. It helps to compare the tire series, sidewall treatment, construction details, and wheel-width suitability for the specific wheel on the car. That approach keeps the decision grounded in fitment and appearance instead of relying on the name alone.

A period-style 1978 Jaguar XJS tire choice usually starts with deciding between the ER70-15 alphanumeric radial format and a 205/70R15 metric radial. ER70-15 carries a more vintage late-1970s size presentation, while 205/70R15 opens up a broader range of modern-looking radial options in the same 15-inch fitment class.

Appearance goals should guide the final decision. Buyers chasing a more era-conscious look may prefer the alphanumeric format or a blackwall radial with a traditional presentation, while others may want a whitewall treatment that complements the car’s finish and trim. For exact originality, marque literature and vehicle-specific historical references remain the right final check.

On a restored 1978 Jaguar XJS, construction affects appearance less through sidewall shape alone and more through the tire’s overall presentation. This car’s covered primary fitments are radial, but the visual difference between a modern metric radial, an alphanumeric radial, and a bias-look radial can still be noticeable on a finished restoration.

That means the tire should be chosen as part of the car’s full visual composition, including wheel style, ride height, and sidewall treatment. A modern blackwall can look more contemporary, while an alphanumeric or bias-look radial can feel more in step with the period. The best choice depends on whether the restoration leans preservation-focused, touring-oriented, or visually personalized.

Yes. A 1978 Jaguar XJS may share standard 15-inch fitment choices, but aftermarket wheels, wheel-width changes, suspension alterations, or body modifications can all affect whether a given tire remains suitable. That matters with both 205/70R15 and ER70-15 because correct diameter alone does not settle every fitment question.

The safest approach is to inspect the actual wheel and surrounding clearance before choosing a tire. Steering clearance, fender space, and the wheel’s true dimensions deserve a look, especially on a car that may have changed hands several times. A restored or modified XJS should always be measured as it sits rather than assumed to match stock layout.

Before driving a 1978 Jaguar XJS on new tires, confirm the wheel diameter and width, verify that each tire is seated and inflated properly, and look for adequate clearance at the fenders and steering components. On a low-use collector car, it also makes sense to inspect suspension condition and alignment-related wear points before putting fresh tires into service.

A careful walk-around after installation can prevent early problems. Check for rubbing at full steering lock, uneven stance, visible interference, or air loss after the first drive. It is also smart to monitor pressure closely during the initial use period, since collector cars often sit for long stretches and may reveal wheel or valve issues once they return to the road.

205/70R15 tires on a collector 1978 Jaguar XJS should be maintained with regular pressure checks, visual inspections for cracking or bulges, and periodic checks for uneven tread wear. Because cars like the XJS are often driven less frequently, tire age and storage conditions can matter as much as mileage when evaluating overall condition.

Long-term care also includes storing the car away from prolonged sunlight, heat, moisture, and ozone sources when possible. Driving the car often enough to avoid long flat-spotting periods can also help. Before any longer trip, look closely for air loss, cuts, or sidewall damage so the car’s grand touring character is supported by sound tire condition.