The 1973 Imperial came from Chrysler’s final years of true full-size luxury excess, when ride isolation, long-wheelbase comfort, and formal styling still defined the top end of the American market. On a car of this size and character, tire choice has a real effect on both stance and road manners. The 1973 Imperial All Models uses either an L84-15 bias-ply tire or an LR78-15 radial on a 15-inch rim. That gives owners a meaningful decision between traditional bias-ply fitment and a period-style radial presentation. The right choice depends on whether the goal is restoration-oriented appearance, radial road use, or staying close to the car’s original-era tire construction.
Which Tire Size Is Right for The 1973 Imperial All Models
The 1973 Imperial All Models uses two primary tire sizes, and the difference centers on construction rather than wheel diameter since both fit a 15-inch rim. The Base sub-model uses either L84-15 bias-ply or LR78-15 radial, so the first step is deciding whether to stay with a traditional bias-ply setup or move toward a radial fitment with a similar period presentation.
L84-15 is a vintage alphanumeric bias-ply size in which the letter identifies the tire’s size class, the series marking places it within an older profile family, and the 15 refers to the wheel diameter. On a 1973 Imperial, this size represents the traditional bias-ply construction associated with large American luxury cars of the period. Its role is less about modern sizing language and more about preserving the car’s original-era look and feel. This size is the one to evaluate if maintaining a restoration-oriented presentation and bias-ply construction matters most on your Imperial.
LR78-15 is an alphanumeric radial size, with the R marking radial construction and the final 15 indicating a 15-inch wheel. For the 1973 Imperial, it provides a radial-format option while staying within an era-appropriate sizing convention rather than switching to a later metric tire code. Available LR78-15 product choice centers on Firestone’s Wide Oval Radial series with a narrow whitewall and a bias-look radial profile. This size deserves attention if the goal is a more traditional-looking radial setup on the Imperial’s original rim diameter.
Fitment is straightforward on the covered 1973 Imperial sub-model, because the same two 15-inch tire sizes are used within the range. Checking the sub-model still helps confirm whether the car is being kept in bias-ply form or set up with the radial alternative.
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1973 Imperial All Models Base
The 1973 Imperial All Models Base uses either L84-15 bias-ply or LR78-15 radial tires on a 15-inch rim. That gives the owner a clear construction choice between a traditional period-style bias-ply fitment and a radial option with a vintage visual character.
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 1973 Imperial All Models Tires for Sale
Available product choice for the 1973 Imperial centers on LR78-15 radial fitment, with Firestone offering the Wide Oval Radial series in a narrow whitewall bias-look radial design. That makes sidewall appearance, construction style, and rim-width compatibility the key comparison points in the product grid.
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Bias Profile Radial
Firestone Steel Belted 721 |.75 Inch Whitewall | LR78-15
These FAQs focus on 1973 Imperial tire size, 15-inch rim fitment, bias-ply versus radial construction, restoration-minded selection, and the checks worth making before putting a large collector luxury car back on the road.
Tire Size & Fitment
What tire size fits a 1973 Imperial All Models?
The 1973 Imperial All Models uses two primary tire sizes: L84-15 in bias-ply construction and LR78-15 in radial construction. Both sizes apply to the covered Base sub-model and both are built for a 15-inch rim, so the main fitment distinction is construction type rather than wheel diameter.
That means the decision is not simply about finding any 15-inch tire. It is about matching the Imperial’s existing wheel setup and deciding whether the car will stay with a traditional bias-ply presentation or use the radial-format alternative. On a collector car, wheel width, clearance, and any prior modifications are worth confirming before choosing between the two.
What size rim does a 1973 Imperial All Models use?
The primary tire sizes for the 1973 Imperial All Models both use a 15-inch rim. That applies to L84-15 bias-ply fitment and LR78-15 radial fitment, so wheel diameter stays consistent even though the construction format changes between the two tire sizes.
Rim diameter is only the first checkpoint, especially on a large luxury car that may have seen wheel changes over the years. The actual wheel width should also be verified before selecting a tire, particularly if the Imperial has aftermarket wheels or an older restoration. Staying with the correct 15-inch diameter helps narrow the search, but it does not replace a full wheel and clearance check.
Does the 1973 Imperial All Models Base use the same tire size?
The 1973 Imperial All Models Base uses the same two tire-size choices covered for this application: L84-15 bias-ply and LR78-15 radial. Both are intended for a 15-inch rim, so the sub-model does not introduce a separate wheel diameter or a different primary sizing family.
That simplifies the search, but the Imperial still presents a choice between two distinct constructions. A buyer can focus on whether the car is being kept in a more traditional bias-ply configuration or equipped with a radial that suits period-style appearance. Looking at the current wheels and the car’s intended use usually makes that decision much clearer.
Bias-Ply & Radial Options
Is L84-15 a bias-ply or radial tire for the 1973 Imperial All Models?
L84-15 is the bias-ply tire size for the 1973 Imperial All Models. It is a vintage alphanumeric bias-ply format built for a 15-inch rim, and it represents the traditional construction style associated with full-size American luxury cars from this era.
Choosing L84-15 makes the most sense when preserving an original-era tire type matters more than moving to a radial-format option. Since this is a large, heavy collector car, the actual wheel condition and width still deserve attention before mounting any new tires. Construction choice should also match the car’s restoration direction and the way it will be driven.
Should I use bias-ply or radial tires on a 1973 Imperial All Models?
A 1973 Imperial All Models can be set up with either L84-15 bias-ply or LR78-15 radial fitment, both on a 15-inch rim. The bias-ply option keeps the car in a more traditional tire construction, while the LR78-15 radial format gives owners a period-style radial alternative within the same basic wheel diameter.
The better choice depends on the direction of the car rather than a one-size-fits-all answer. A restoration-oriented Imperial may stay bias-ply for authenticity of presentation, while a road-driven car may lead the owner toward radial construction. Wheel width, overall tire dimensions, and body or suspension changes should still be checked before making the switch.
What should I check before converting my 1973 Imperial All Models from bias-ply to radial tires?
Start by confirming that the Imperial still has the correct 15-inch wheels and that the wheel width matches the radial tire being considered. A conversion from L84-15 bias-ply to LR78-15 radial changes construction type, so the tire should be evaluated against the wheel, the vehicle’s stance, and the available clearance.
The next step is checking practical fitment details on the actual car. Steering travel, fender clearance, suspension condition, and any prior wheel or ride-height changes all matter on a long, full-size vehicle like the Imperial. Mixing construction types front to rear also deserves caution, so the overall tire setup should be considered as a complete package.
Choosing the Right Tire
What should I consider when choosing a tire for a 1973 Imperial All Models?
Begin with the correct primary fitment: L84-15 if the goal is bias-ply construction, or LR78-15 if the car is being fitted with the radial option. Both use a 15-inch rim, so the key decision centers on construction type and how closely the tire choice should reflect the Imperial’s original-era character.
After size and construction, look at how the car will actually be used. A restoration-focused Imperial may favor traditional appearance, while a touring-oriented car may place more weight on radial fitment. Wheel width, load capability, sidewall style, and the overall look of the tire on a large formal-body car all deserve a careful side-by-side comparison.
What sidewall styles are available for 1973 Imperial All Models tires?
The available LR78-15 product offering for the 1973 Imperial All Models uses a narrow whitewall sidewall treatment. On a car from this luxury segment, sidewall style plays a major visual role because the tire is highly visible against the Imperial’s substantial body and formal proportions.
A narrow whitewall gives the car a distinctly period-style look without requiring a broad decorative sidewall. That can be especially appealing on a 1973 Imperial that is being kept visually close to its era. Sidewall choice should still be balanced against the correct size, the desired construction, and the appearance of the car’s current trim and wheel setup.
What brands offer tires for the 1973 Imperial All Models?
Firestone is represented in the available LR78-15 fitment for the 1973 Imperial All Models. The radial product offering is the Firestone Steel Belted 721 in the Wide Oval Radial series, combining a bias-look radial profile with a narrow whitewall sidewall treatment.
Brand is only one part of the decision on a car like this. The Imperial’s size and luxury-car presence make construction style, sidewall appearance, and wheel compatibility just as important as the name on the sidewall. Once the correct tire size has been confirmed, comparing the visual character and specifications of the available product becomes the more useful next step.
Restoration & Appearance
Which tire should I choose for a period-style 1973 Imperial All Models?
A period-style 1973 Imperial All Models can be approached in two ways: L84-15 for traditional bias-ply construction, or LR78-15 for a radial option that still stays within an era-appropriate alphanumeric format. The better choice depends on whether the car is being restored toward original-type construction or set up for more regular road use.
Visual priorities matter on a formal luxury car, because tire profile and sidewall treatment influence the whole stance of the vehicle. Buyers seeking exact originality should compare their car against marque-specific restoration references and historical documentation. Buyers focused on period flavor rather than strict authenticity can choose the construction that best matches how the Imperial will actually be used.
How does tire construction affect the appearance of a restored 1973 Imperial All Models?
Tire construction changes more than the way the car drives; it also changes how a restored 1973 Imperial presents itself. An L84-15 bias-ply keeps the Imperial in a traditional tire format from its era, while an LR78-15 radial keeps the same 15-inch wheel diameter but moves the car into a radial-style construction.
That difference can influence how authentic or updated the car feels at a glance, especially on a large luxury body with prominent wheel openings. Sidewall treatment adds another layer, since the available LR78-15 product uses a narrow whitewall. For many restorations, the final choice comes down to balancing historical presentation with intended road use rather than treating appearance and function as separate issues.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1973 Imperial All Models?
Yes, modifications can affect tire fitment on a 1973 Imperial All Models even when the car is using the correct primary size family. Aftermarket wheels, changes in wheel width, suspension work, ride-height changes, or body repairs around the wheel openings can all alter how an L84-15 or LR78-15 tire sits on the car.
That matters because the Imperial is a large, heavy vehicle with a lot of visual and physical space tied up in its tire and wheel package. A previous owner may have changed components without preserving original dimensions. Measuring the actual wheel setup and checking clearance at steering lock and through suspension movement helps prevent unpleasant surprises after mounting new tires.
What should I inspect before driving a 1973 Imperial All Models on new tires?
Before taking a 1973 Imperial All Models on the road with new tires, inspect the wheels, valve stems, lug hardware, and overall mounting condition. Tire pressure should be set correctly for the chosen tire, and the car should be checked for visible clearance issues, especially at the fenders and during steering movement.
A collector luxury car often spends long periods parked, so a broader inspection is wise before any serious drive. Look over suspension components, steering response, and brake condition, then watch for air loss or unusual contact after the first miles. A short local test drive is a good way to confirm that the new tires are behaving normally before heading farther from home.
How should tires on a collector 1973 Imperial All Models be maintained?
Tires on a collector 1973 Imperial All Models should be maintained with regular pressure checks, periodic visual inspection, and attention to age-related condition as well as tread. Sidewall cracking, bulges, cuts, flat spotting, and slow air loss all deserve attention, especially on a car that may spend more time stored than driven.
Storage habits make a real difference on a low-use Imperial. Keeping the car away from prolonged sunlight, moisture, and ozone sources helps protect the rubber over time, and moving the vehicle periodically can reduce long-term stress on one contact patch. Even a good-looking tire should be evaluated carefully before extended road use if the car has been sitting for long stretches.
