1973 Imperial Tire Fitment Guide

1973 Imperial vehicles use two tire sizes: L84-15 and LR78-15. Both sizes apply across all 1973 Imperial models rather than being assigned to separate body styles or model families, and both mount on 15-inch wheels. LR78-15 has an approved rim width range of 5.50 to 8.00 inches, which gives a useful reference point when checking an existing wheel.

That means most buyers start by deciding which construction they want, not by sorting through different model fitments. L84-15 is the traditional bias-ply choice for a more period-authentic setup, while LR78-15 is the radial alternative. Before ordering, confirm the tire size already on the car, inspect the wheel diameter stamping, and verify that the wheel width falls within the tire maker’s approved range where that information is available.

L84-15 is an alphanumeric bias-ply size used on 1973 Imperial vehicles. In that older sizing system, the letter-and-number combination identifies the tire’s size class, while the 15 refers to the wheel diameter in inches. Because there is no R in the code, it is a bias-ply construction rather than a radial.

For a 1973 Imperial owner, that size points toward the type of tire many American luxury cars of the era would have used when new. It matters most when originality is part of the goal, whether for a restoration, a period-correct visual stance, or a driving feel that matches the car’s original character more closely than a later radial replacement.

LR78-15 is an alphanumeric radial size for 1973 Imperial vehicles. The L and 78 identify the tire’s size and profile family within the period alphanumeric system, the R marks it as a radial, and the 15 means it fits a 15-inch wheel. On this application, it serves as the radial alternative to the bias-ply L84-15.

That distinction is useful because many owners recognize the size code but are not sure what changed once radial construction entered the market. On a 1973 Imperial, LR78-15 is the better place to start if you want a tire with radial construction while keeping a look that still suits a large early-1970s luxury car. The wheel diameter still needs to be confirmed, but the code itself tells you a great deal about the tire’s design.

Yes. All 1973 Imperial models share the same two tire size options: L84-15 and LR78-15. There is no model-by-model split within the 1973 Imperial range here, so the fitment question is consistent across the marque for that year rather than varying by a different Imperial body or trim grouping.

That makes the buying process simpler than it is for many multi-model year-and-make pages. Once you have confirmed that your car is a 1973 Imperial and that it still uses the correct 15-inch wheel diameter, the next step is deciding whether you want bias-ply authenticity or radial construction. After that, sidewall appearance and wheel-width compatibility become the details to verify.

For a 1973 Imperial, the choice between L84-15 and LR78-15 is mainly a choice between bias-ply and radial construction. L84-15 is the period-style bias-ply size and fits the kind of tire specification buyers would associate with a correct early-1970s luxury-car presentation. LR78-15 is the radial alternative, and in this application it is available as a Firestone bias-look radial with a narrow whitewall.

Choose L84-15 when visual authenticity and era-correct construction are the priority. Choose LR78-15 when you want radial construction while preserving a traditional appearance that still suits the car. Since both use a 15-inch rim diameter, the decision is less about basic fit and more about how you plan to use the car, how original you want it to appear, and whether your wheel width matches the tire’s approved range.

1973 Imperial tires include a narrow whitewall option in LR78-15 through Firestone. That sidewall treatment fits the formal, upscale look buyers typically expect on a full-size American luxury car from this era, especially one positioned above Chrysler’s mainstream models. Whitewall style has a strong effect on the car’s visual period character even when the wheel size stays the same.

Sidewall choice matters for both restoration and overall presentation. A narrow whitewall generally suits a 1973 Imperial far better than an aggressively modern appearance, especially if the car still carries its original trim, wheel covers, and ride height. If you are building the car for judged events, compare the sidewall style on your target tire with period photos, factory literature, and marque-club guidance before making the final choice.

Firestone makes a 1973 Imperial tire in LR78-15, offered as the Steel Belted 721 in a narrow whitewall, bias-look radial configuration. That gives 1973 Imperial owners a branded radial option in the correct alphanumeric size family for a full-size American luxury car using a 15-inch wheel.

Brand matters most when it shapes the tire’s visual character and construction style, not just the name on the sidewall. For a 1973 Imperial, the available Firestone radial option is especially relevant to owners who want a recognizable heritage brand and a vintage appearance. If you are trying to decide between staying with a bias-ply size or moving to a radial, compare the construction first and treat brand as the finishing preference.

For 1973 Imperial vehicles using LR78-15, the approved rim width range is 5.50 to 8.00 inches on a 15-inch diameter wheel. That is the wheel-width window to verify against the car before fitting that radial size. L84-15 also uses a 15-inch wheel diameter, though wheel-width approval should always be matched to the exact tire maker’s specification for the product you choose.

Rim width matters because it affects sidewall shape, tread profile, and the way the tire sits on the car. A wheel that is too narrow or too wide for the tire can change appearance and behavior even if the bead seats on the rim. The safest approach is to measure the wheel, confirm the stamped diameter, and compare the actual width to the approved range for the exact size and construction you plan to run.

LR78-15 for 1973 Imperial is offered without a tube-type marking in the available Firestone radial product information. That points to a tubeless-style radial application, but wheel condition and wheel design still matter on any older collector car. Tube use should always follow the exact tire maker’s guidance and the condition of the wheel the tire will be mounted on.

Many owners assume every older car automatically needs tubes, but that is not always the case. On a 1973 Imperial, the better habit is to inspect the wheel carefully for corrosion, pitting, or damage that could affect sealing, then match the mounting method to the tire and wheel combination you are actually using. If the car has older wheels of uncertain condition, a tire shop experienced with vintage vehicles is worth involving early.

Yes, both tire sizes used on 1973 Imperial vehicles share a 15-inch rim diameter, so the original wheel diameter is compatible with either size. That is why the main split on this application is construction type rather than a change in wheel diameter from one tire size to the other.

Wheel diameter compatibility does not automatically settle every fitment detail, though. The wheel still needs to be the proper width for the exact tire you choose, and the rim should be in sound condition before mounting a new collector tire. If your Imperial still wears original wheels, confirm the diameter and width first, then compare them with the tire maker’s approved range before committing to a size.

A stored 1973 Imperial should be kept in a cool, dry, dark place away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment. Tire pressure should be maintained during storage, and the car should be moved periodically to avoid one spot carrying the load for months at a time. Bias-ply tires tend to flat-spot more readily during long static storage than radials.

That matters on a large luxury car because curb weight and long periods of inactivity can age the tires faster than mileage would suggest. If the car will sit for an extended season, clean the tires gently, avoid petroleum-based dressings, and consider stands or periodic rolling to reduce stress on one area of the casing. A breathable indoor cover helps the car, but tire protection from UV and ozone is just as important.

Tires on a 1973 Imperial should be judged more by age than by mileage. A collector tire often reaches the point of careful evaluation around five to seven years, and many owners treat ten years as the outer range for serious replacement consideration regardless of remaining tread. The DOT date code on the tire sidewall is the starting point for understanding its age.

That age-based approach is especially important for a car that may only be driven occasionally to shows, cruises, or weekend events. Low mileage can hide internal aging, weather checking, and hardening that are not obvious from tread depth alone. If the tire is older, has spent time in heat or sunlight, or shows any cracking, have it inspected and weigh replacement before planning regular road use.

Tires on a 1973 Imperial should be inspected before every drive and again before any longer outing. Check for sidewall cracking, cuts, bulges, uneven wear, and pressure loss, and make sure the spare is still serviceable. On an older luxury car, a quick visual inspection can catch age-related issues well before they turn into roadside problems.

A more thorough inspection a few times each season is wise even if the car is driven sparingly. Look closely at the beads, valve stems, tread blocks, and any area that has been resting on the ground during storage. If the car has sat for a long period, the first drive of the season is the wrong time to discover a weak valve stem, dry cracking, or a tire that no longer holds pressure consistently.

A 1973 Imperial All Models application belongs to the period when American luxury cars were transitioning toward broader radial acceptance, but bias-ply construction still remained closely tied to original presentation. In this fitment family, L84-15 represents the period-style bias-ply size, while LR78-15 is the radial counterpart. Both fit a 15-inch wheel, which matches the era’s large-car luxury practice.

For a restoration, that usually means starting with the visual and judging goal of the car rather than assuming any early-1970s tire is automatically correct. If the car is being restored to a showroom-style appearance, a bias-ply size often aligns more closely with originality expectations. If market, build date, or trim-specific confirmation matters, factory literature and Imperial or Chrysler marque specialists are the right places to verify the final detail.

Yes, correct tire fitment matters on a 1973 Imperial when the car is judged for authenticity. Size, construction type, sidewall treatment, and overall period appearance all influence whether the tire looks appropriate for an early-1970s flagship luxury car. A modern-looking replacement, even in a workable diameter, can stand out immediately against the car’s formal styling and original trim.

The practical question is not only whether the tire fits the wheel, but whether it matches the standard of the event. A bias-ply setup may be more convincing for originality-focused judging, while a radial with a bias-look profile and correct whitewall style may suit a touring or driver-level restoration. Event rules vary, so compare your target tire with period photos and consult marque-club judging guides before finalizing the car.

Whitewall appearance is a major styling element on a 1973 Imperial restoration because the tire sidewall contributes heavily to the car’s luxury presentation. The available LR78-15 Firestone option uses a narrow whitewall, which fits the restrained but upscale look associated with early-1970s domestic prestige cars. On a vehicle with formal lines and substantial brightwork, sidewall styling can change the whole stance of the car.

That means restoration decisions should weigh appearance almost as carefully as size and construction. A sidewall that is too modern, too plain, or visually out of period can make an otherwise accurate car look off at a glance. If originality is the goal, compare the car against period brochures, advertising photography, and surviving unrestored examples so the whitewall treatment complements the rest of the restoration rather than fighting it.

1973 Imperial tires can be suitable for highway driving when they are in good condition, properly inflated, matched to sound wheels, and used within the tire’s intended limits. LR78-15 is available in a radial construction, which many owners prefer for regular road use on a large luxury car. With any 1973 Imperial, the car’s own age, braking system, suspension condition, steering wear, and alignment are just as important as the tire itself.

Highway safety is never just a tire question on a fifty-plus-year-old car. A fresh tire cannot compensate for worn front-end parts, weak shocks, stale brake hoses, or poor wheel balance. Before planning sustained highway use, inspect the tires closely, verify pressure when cold, and make sure the Imperial tracks straight and stops cleanly. The goal is a matched system, not simply a tire that happens to fit the rim.

For 1973 Imperial vehicles using the Firestone LR78-15 radial, the tire carries a maximum load of 1,970 pounds at 32 psi. That figure is the tire’s rated load-and-pressure limit for that product, not automatically the exact running pressure every Imperial should use in service. Factory operating pressure should still be checked against the car’s original literature and adjusted for the specific tire construction you are using.

The key point is not to transfer one pressure number blindly from one size or tire type to another. Bias-ply and radial constructions can respond differently, and a reproduction-style collector tire may have its own recommended operating range. Start with the vehicle’s guidance where available, compare it with the tire maker’s rating information, and make sure all four tires are set evenly when cold before evaluating ride, steering feel, and wear pattern.

Before a longer drive in a 1973 Imperial, inspect each tire for cracking, punctures, bulges, unusual wear, and pressure loss, and check the valve stems and spare at the same time. Confirm that the tires are the same size and construction side to side on each axle unless a deliberate, well-understood setup is being used. A long-wheelbase luxury car is especially sensitive to tired suspension and underinflated tires on the open road.

Treat the tires as one part of a broader pre-trip inspection. Wheel bearing condition, brake function, steering response, fluid levels, belts, hoses, and cooling-system health all deserve attention before asking a 1973 Imperial to cover distance. If the car has been sitting, do a shorter local drive first and recheck pressures and wheel balance afterward. That approach helps catch issues early instead of discovering them several exits from home.