1979 Jaguar Tire Fitment Guide

1979 Jaguar vehicles use two tire sizes: ER70-15 and 205/70R15. ER70-15 applies to the XJ12C, XJ12L, XJ6, and XJS, while 205/70R15 applies to the XJ6 and XJS. Both sizes mount on 15-inch wheels. In 205/70R15, approved rim-width ranges run from 5.00 to 7.50 inches depending on the specific tire, with individual products spanning 5.00-7.00, 5.50-7.50, and 5.0-7.0 inches.

That means the first fitment question for a 1979 Jaguar is model identification, not just year and make. An XJ12C or XJ12L points you straight to ER70-15, while an XJ6 or XJS requires a closer look at the car's existing size, wheel, and intended appearance. Once the size is confirmed, you can narrow the choice by sidewall style, speed rating, and brand character rather than guessing between two interchangeable sizes.

ER70-15 is an alphanumeric radial size used during the transitional years when many European and luxury cars still carried letter-based radial sizing. The letter prefix identifies the overall size class, the R denotes radial construction, and the 15 indicates a 15-inch wheel. On 1979 Jaguar models, ER70-15 appears across the whole range here, covering the XJ12C, XJ12L, XJ6, and XJS.

For a 1979 Jaguar owner, that code matters because it reflects the period-correct sizing language Jaguar buyers would have seen in the late 1970s. If your car still wears ER70-15 on the sidewall, keeping that format usually preserves the right visual character for a factory-style restoration. It also helps separate an original-style late-1970s fitment path from the metric 205/70R15 size used on some XJ6 and XJS applications.

No. ER70-15 is shared by all four 1979 Jaguar models covered here, but 205/70R15 is used only on the XJ6 and XJS. The XJ12C and XJ12L stay with ER70-15, while the XJ6 and XJS can appear with either size depending on the car. Every size in this group uses a 15-inch rim, but the sidewall code and exact dimensional standard are not the same across the range.

That variation is important because a 1979 Jaguar buyer cannot assume one size fits every XJ- or XJS-badged car from the year. A sedan or coupe owner who orders by year and make alone can easily end up comparing the wrong size family. The best path is to identify the exact model, read the current tire size on the car if possible, and confirm the wheel before choosing between an alphanumeric radial and a metric radial.

The right choice depends first on which 1979 Jaguar you own. ER70-15 works across the full model group here, while 205/70R15 is used only on the XJ6 and XJS. Both are radial 15-inch sizes, so this is not a bias-ply-versus-radial decision; it is a fitment and period-format decision. ER70-15 keeps the late-1970s alphanumeric radial convention, while 205/70R15 uses modern metric sizing language.

If you are restoring a 1979 Jaguar to look as close as possible to its original late-1970s presentation, ER70-15 is often the first size to consider where it applies. If you have an XJ6 or XJS already running 205/70R15, staying with that size may simplify replacement and open more choices in speed rating and sidewall appearance. The deciding factor should be the car's actual size application and the look you want, not a guess based on the model family alone.

Sidewall style variety is centered on the 205/70R15 size used on certain 1979 Jaguar XJ6 and XJS cars. That size is available in blackwall, narrow whitewall, and wide whitewall forms. Michelin and Avon appear in blackwall versions, while Maxxis offers a narrow whitewall and American Classic offers a wide whitewall. The ER70-15 size remains the more traditional late-1970s Jaguar size path, but the sidewall variety shown here comes from the metric option.

For most 1979 Jaguar restorations, blackwall is the most natural visual choice, especially on sportier or more European-market-looking cars. Whitewall width becomes a styling decision as much as a fitment one, and wider whitewalls tend to push the car toward a more formal luxury presentation than many enthusiasts associate with Jaguar's original sporting image. If appearance matters as much as fit, decide on sidewall style before narrowing to a particular brand or series.

Four brands cover the 205/70R15 size used on some 1979 Jaguar vehicles: Maxxis, Michelin, Avon, and American Classic. All four are radial tires, but they serve slightly different buyer priorities. Michelin and Avon focus on blackwall performance-oriented or European-style presentation, while Maxxis and American Classic add whitewall choices for owners who want a different visual treatment on an XJ6 or XJS.

Brand choice on a 1979 Jaguar often comes down to balancing authenticity, appearance, and the way the car is used. Michelin and Avon have strong appeal for enthusiasts who want a tire that looks at home on a European grand tourer or saloon. Maxxis and American Classic become more relevant when whitewall appearance is part of the plan. Once the size is confirmed, compare each brand's sidewall style, speed rating, and approved rim-width range instead of choosing by name alone.

Rim-width guidance is available for the 205/70R15 tires used on certain 1979 Jaguar models, and it varies by product. Maxxis and Avon fit 5.00 to 7.00-inch rims, while Michelin and American Classic fit 5.50 to 7.50-inch rims. All of those tires share a 15-inch rim diameter. That gives the 205/70R15 size family an overall approved range of 5.00 to 7.50 inches depending on the exact tire you choose.

The practical takeaway is that wheel width should be checked against the specific tire, not assumed from the size code alone. A 1979 Jaguar owner moving between brands may find that one 205/70R15 works on a narrower wheel while another wants a slightly wider one. Confirm the wheel before ordering, especially if the car has replacement rims or if you are trying to preserve the original steering feel and sidewall profile Jaguar intended.

Tubeless status is confirmed for the Michelin 205/70VR15 used on certain 1979 Jaguar applications, which is marked TL. Other 205/70R15 products do not all carry the same tube marking in the available specifications, so tube status can vary by product rather than by size alone. Both Jaguar sizes here are radial 15-inch fitments, but the correct tube or tubeless setup still depends on the individual tire and the wheel it is being mounted on.

That matters because a tubeless-capable tire still depends on a wheel in suitable condition to seal properly. On a 1979 Jaguar with original wheels, age, corrosion, and rim condition can affect whether a tubeless installation is practical. Before mounting, confirm the sidewall marking on the exact tire you choose and inspect the wheel carefully. If there is any doubt, a tire professional familiar with older British wheels can help determine the right setup.

Both tire sizes used on 1979 Jaguar models mount on 15-inch wheels, so there is basic rim-diameter compatibility between ER70-15 and 205/70R15. That said, the approved rim-width range should still be checked against the exact tire and wheel. In the 205/70R15 size, products span from 5.00-inch minimum approved width to 7.50-inch maximum approved width depending on brand and series.

For an XJ6 or XJS, that means a 15-inch original wheel may accept either size in principle, but width and wheel condition still need to be verified before making a switch. For an XJ12C or XJ12L, the main issue is less about interchanging sizes and more about staying with the correct model application. When originality matters, keeping the proper sidewall format for the car is often just as important as confirming diameter.

A stored 1979 Jaguar should be kept in a cool, dry, dark garage away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment that can accelerate sidewall aging. Keep the tires inflated to an appropriate storage pressure, park on a clean surface, and move the car periodically if possible. Radials usually resist flat-spotting better than older bias-ply designs, but they still age from heat, ozone, and long static loading.

Long-term storage habits affect both appearance and drivability on a collector Jaguar. If the car will sit for months, rolling it occasionally or supporting it in a way that reduces constant load can help prevent a temporary vibration on the next drive. A breathable car cover, clean wheels, and regular pressure checks also matter. Storage care is especially important on low-mileage luxury cars, where tires often age out before they wear out.

Tires on a 1979 Jaguar are usually replaced on age more than mileage. A good collector-car rule is to begin close inspection around five to seven years of age and to treat ten years as the outer edge for serious replacement consideration, even if the tread still looks strong. The DOT date code on the tire sidewall gives the manufacturing week and year, which is more useful than odometer mileage for a low-use classic.

That age-based approach matters because Jaguars of this era are often driven occasionally, not daily, and cosmetic condition can hide internal hardening or carcass aging. A tire that still looks attractive on an XJ6 or XJS may no longer deliver the ride quality or security expected on a longer trip. If the date code is older than you expected, let tire age weigh heavily in the decision even before visible cracks become obvious.

Tires on a 1979 Jaguar should be checked before every drive, with a more thorough inspection before any extended outing. Look for cracking at the sidewall and tread base, uneven wear, bulges, cuts, embedded objects, and loss of pressure. On cars using a tubeless setup, inspect the valve stems and bead area as well, since age at the wheel can matter almost as much as age in the tire itself.

That routine is especially important on a heavy, fast touring car like a late-1970s Jaguar, where smooth cruising can hide tire issues until speeds rise. A quick visual walkaround is not enough before a trip. Put a gauge on all four tires, inspect the spare, and pay attention to any new vibration or steering pull on the first miles out. Catching an aging tire early is much easier than dealing with one after it fails on the road.

A 1979 Jaguar XJ6 from this group appears with either ER70-15 or 205/70R15, and both are radial sizes. That aligns with the period, since a late-1970s Jaguar saloon would ordinarily have been a radial-tire car rather than a bias-ply car. ER70-15 reflects the alphanumeric radial language common in the era, while 205/70R15 reflects metric sizing that had become increasingly familiar by the late 1970s.

For restoration work, the safest approach is to match the car's existing verified fitment, original literature, or a trusted Jaguar marque specialist rather than assuming every XJ6 used the same sidewall code. Market differences, wheel changes over time, and previous owner substitutions can complicate the picture. If the car is headed for judged competition, use club and event guidance to confirm whether the expected presentation is alphanumeric radial, metric radial, blackwall, or another period-correct variation.

Yes, correct tire fitment matters on a shown 1979 Jaguar because judges and knowledgeable enthusiasts notice size format, construction type, and sidewall appearance quickly. A late-1970s Jaguar should present as a radial-tire car, and the difference between ER70-15 and 205/70R15 can affect how authentic the car looks for its exact model and setup. Sidewall style matters too, especially if the car is restored toward a factory-style European presentation.

On a concours-oriented XJ or XJS, the wrong sidewall treatment or an obviously non-period size code can distract from an otherwise excellent restoration. Even if the tire physically fits, it may not look right to someone familiar with Jaguar practice of the period. Before finalizing a show car, compare your tire choice with original photos, handbook material, and Jaguar club guidance so the finished car aligns with the judging standard you are aiming for.

Yes, radial tires are correct for 1979 Jaguar vehicles in this range. Both sizes used here, ER70-15 and 205/70R15, are radial constructions, which fits Jaguar's late-1970s position as a maker of refined high-speed luxury and grand-touring cars. By that point, a radial sidewall and tread profile were part of the driving character owners expected from an XJ sedan or XJS rather than an exception to period practice.

That makes restoration decisions simpler than on many earlier classics, because the construction question is already settled in favor of radial tires. The finer authenticity question is usually which radial size format your particular car should wear and whether the sidewall should be blackwall or a whitewall variation. If originality is the goal, focus on matching the right radial size code for the model before debating brand preference.

Yes, 1979 Jaguar tires can be suitable for highway driving when they are the correct size, in sound condition, and matched to the car's intended use. In 205/70R15, available speed ratings include V-rated products up to 149 mph and W-rated products up to 168 mph, which are more than adequate for normal U.S. highway use. As with any collector Jaguar, tire condition, age, inflation, and the car's mechanical state matter more in everyday driving than headline speed capability.

A healthy tire does not make an unrestored suspension, aged brake system, or neglected steering safe at speed, so the whole car has to be considered together. On a 1979 Jaguar, that is especially true because these are refined touring cars that can feel composed even when maintenance is overdue. Before regular highway use, confirm tire age, inspect for cracking, and make sure the chassis and braking system are as ready as the speed-rated rubber.

Inflation pressure for a 1979 Jaguar should follow the vehicle's factory recommendation first, then be checked against the tire manufacturer's own rated limits. In the 205/70R15 size, some products carry a maximum load of 1,499 pounds at 35 psi. That figure is a tire rating, not a universal operating pressure for every 1979 Jaguar or every tire in every size. Pressure should never be copied from one size family to another without confirmation.

The practical approach is to start with the pressure Jaguar recommended for your exact model, then confirm that the tire you choose is being used within its own load and pressure envelope. This matters on cars like the XJ6 and XJS, where two different radial size conventions can appear. If the car has been modified, corner-weighted, or fitted with non-original wheels, a marque specialist or experienced alignment shop can help refine pressure from that starting point.

Before a longer drive in a 1979 Jaguar, inspect all four tires and the spare for cracking, cuts, bulges, embedded debris, irregular wear, and proper inflation. Check valve stems, confirm the tires are the correct size for the car, and make sure the wheels are in good condition for the mounting type used. A long-trip inspection should also include a quick look at tread depth and any signs that one corner of the car is carrying wear differently from the others.

Tires are only one part of a proper pre-trip check on a late-1970s Jaguar, but they are the easiest place to catch problems before leaving home. If the car has been sitting, drive the first few miles gently and pay attention to vibration, pulling, or thumping that was not there before. Pair the tire inspection with checks of fluids, belts, hoses, brakes, and lights so the car's touring character is matched by touring reliability.