Oldsmobile’s 1978 lineup spanned everything from compact hatchbacks and coupes to full-size sedans, a big front-drive personal luxury car, and a traditional station wagon, reflecting how broad the division’s reach had become in the late 1970s. That variety matters because 1978 Oldsmobile vehicles did not rely on one universal tire size across the range. Seven model lines use 12 distinct sizes, with some models offering both bias-ply and radial-era choices while others are tied to one specific radial size family. Before choosing a tire for a 1978 Oldsmobile, the first step is confirming the exact model, then narrowing the choice to the correct size and construction style for how the vehicle will be used.
Which Tire Size Is Right for Your 1978 Oldsmobile
Twelve tire sizes appear across the 1978 Oldsmobile range, and they vary significantly by model rather than being shared across the full lineup. The real decision starts with identifying the correct model and rim diameter first, then choosing between radial and bias-ply construction where both types were used within the same year and make. Understanding that distinction before choosing a product saves time and helps match the tire to the right Oldsmobile application.
HR78-15 is an alphanumeric radial size in which the letter-and-number code identifies the tire’s relative section class and profile, while the 15 indicates a 15-inch rim. This size is specific to the Custom Cruiser and Ninety-Eight rather than the full 1978 Oldsmobile range. It suits owners who want the radial look and road manners associated with late-1970s full-size Oldsmobiles, while still staying within the period-correct sizing family for those models.
Year(s): 1978|Fit(s): Cutlass|Construction: Radial|Rim: 14 in
195/75R14 is a metric radial size with a 195-millimeter section width, a stated 75-series aspect ratio, radial construction, and a 14-inch rim diameter. It is available from Coker Classic, Tornel, and Maxxis in wide whitewall and narrow whitewall styles, with load capacities ranging from 1,399 pounds at 35 psi to 1,521 pounds at 32 psi. This size is specific to certain Cutlass applications and is a sensible choice for owners who want a radial fitment with a traditional whitewall appearance.
Year(s): 1978|Fit(s): Cutlass|Construction: Radial|Rim: 14 in
205/70R14 is a metric radial size with a 205-millimeter section width, a stated 70-series aspect ratio, radial construction, and a 14-inch rim diameter. It is available from Maxxis and BFGoodrich with narrow whitewall, RWL, redline, and dual-redline sidewall treatments, and BFGoodrich Radial T/A versions carry an S speed rating with a 112 mph ceiling. This size is specific to Cutlass models that benefit from a broader selection of sporty or custom-appearance sidewalls while remaining within a radial 14-inch fitment.
Year(s): 1978|Fit(s): Cutlass|Construction: Radial|Rim: 14 in
185/75R14 is a metric radial size with a 185-millimeter section width, a stated 75-series aspect ratio, radial construction, and a 14-inch rim diameter. It is available from Tornel, Maxxis, and Travelstar in narrow whitewall form, and speed ratings vary by product because some versions carry an S rating with a 112 mph ceiling while others do not show a speed letter in the size marking. This size is specific to certain Cutlass applications and appeals to owners seeking a more conservative radial fitment with a traditional late-1970s whitewall look.
FR78-15 is an alphanumeric radial size whose code places it within the period radial sizing system, with the 15 identifying a 15-inch wheel. This size is specific to the Delta 88 and Omega rather than being universal across 1978 Oldsmobile models. It fits buyers who want to stay with a 15-inch radial setup appropriate to those cars without moving into a different size family.
GR78-15 is an alphanumeric radial size, and the 15 at the end denotes a 15-inch rim diameter. This size is shared by the Delta 88 and Ninety-Eight, making it model-specific within the larger 1978 Oldsmobile range. It is the kind of fitment buyers typically choose when keeping a full-size Oldsmobile in its proper radial-era size family.
Year(s): 1978|Fit(s): Omega|Construction: Bias Ply|Rim: 14 in
E78-14 is an alphanumeric bias-ply size in which the E-series code identifies the tire’s relative section class and the 14 indicates a 14-inch rim. It is available from Coker Classic and STA in wide whitewall and blackwall styles, with load figures reaching as high as 1,710 pounds at 60 psi in certain STA applications. This size is specific to the Omega and is the natural choice for owners focused on a more traditional bias-ply look and feel rather than a later radial driving character.
ER78-14 is an alphanumeric radial size, with the R indicating radial construction and the 14 indicating a 14-inch rim diameter. This size is specific to the Omega and represents the radial counterpart to that model’s bias-ply-era sizing path. It is the better match for owners who want to keep the Omega in a period radial format instead of choosing a bias-ply alternative.
A78-13 is an alphanumeric bias-ply size, with the A-series designation identifying a smaller relative tire class and the 13 denoting a 13-inch rim. This size is specific to the Starfire within the 1978 Oldsmobile lineup. It is best suited to owners aiming for an era-authentic small-car bias-ply presentation rather than a modernized radial approach.
B78-13 is an alphanumeric bias-ply size that uses the older letter-series convention, with the 13 identifying a 13-inch wheel. This size is also specific to the Starfire and is not shared across other 1978 Oldsmobile models. It remains a period-style choice for Starfire owners who want a small-diameter bias-ply fitment consistent with late-1970s subcompact styling.
BR70-13 is an alphanumeric radial size, with the R marking radial construction, the 70 indicating a stated aspect ratio, and the 13 denoting a 13-inch rim. This size is specific to the Starfire and reflects the shift toward lower-profile radial fitments in compact cars of the era. It is the logical direction for owners who want a radial setup for a Starfire rather than one of the model’s bias-ply alternatives.
JR78-15 is an alphanumeric radial size whose code places it at the larger end of the period radial scale, and the 15 denotes a 15-inch rim diameter. This size is specific to the Toronado and reflects that model’s distinct full-size personal luxury role in the 1978 Oldsmobile range. It is the proper starting point for Toronado owners before comparing tread style, sidewall look, or other product-level details.
Seven 1978 Oldsmobile model lines are covered here, ranging from compact and intermediate cars to large sedans, wagons, and personal luxury models. Tire size varies by model, and several models also branch into different sizing families or construction types, so year and make alone are not enough to choose correctly. Select your model below to see model-specific fitment history and the tires that apply to it.
1978 Oldsmobile Custom Cruiser
The Custom Cruiser was Oldsmobile’s full-size station wagon, built for families who wanted traditional GM wagon space and V8-era road presence late into the decade. Its tires mount on 15-inch rims, matching its large-body role and heavier-duty appearance compared with Oldsmobile’s smaller cars.
By 1978, the Cutlass was one of Oldsmobile’s most important nameplates, covering a wide slice of the midsize market with strong everyday appeal and broad trim variety. Its tire choices mount on 14-inch rims, with multiple metric radial sizes reflecting how widely the Cutlass range could vary in stance and appearance.
The Delta 88 sat in Oldsmobile’s full-size family car territory, offering comfortable highway manners and traditional rear-wheel-drive proportions during a downsizing era. Its tires mount on 15-inch rims, and its fitments stay within the alphanumeric radial family used on larger Oldsmobiles of the period.
The Ninety-Eight remained Oldsmobile’s flagship luxury sedan, aimed at buyers who wanted more presence and formality than the Delta 88. Its tires mount on 15-inch rims, and the model uses larger radial sizing families that suit its top-tier place in the lineup.
The Omega was Oldsmobile’s compact entry, sharing the practical mission of GM’s smaller rear-wheel-drive cars while still carrying Oldsmobile styling cues and trim character. Its fitments mount on both 14-inch and 15-inch rims depending on application, and it is one of the few 1978 Oldsmobile models that spans both bias-ply and radial-era size conventions.
The Starfire was Oldsmobile’s sporty subcompact, derived from GM’s H-body platform and aimed at buyers who wanted a smaller car with more style than basic transportation. Its tire choices mount on 13-inch rims, with both bias-ply and radial families reflecting the transitional nature of late-1970s compact fitments.
The Toronado was Oldsmobile’s distinctive front-drive personal luxury coupe, known for combining big-car comfort with a more specialized, upscale identity. Its tire fitment mounts on 15-inch rims and stands apart from the rest of the lineup with its own larger radial size family.
Twelve products are available across four tire sizes for 1978 Oldsmobile vehicles. The 195/75R14 has four radial choices from Coker Classic, Tornel, and Maxxis in wide and narrow whitewall styles; 205/70R14 has four radial choices from Maxxis and BFGoodrich in narrow whitewall, RWL, redline, and dual-redline; 185/75R14 has three radial choices from Tornel, Maxxis, and Travelstar in narrow whitewall; E78-14 has three bias-ply choices from Coker Classic and STA in wide whitewall and blackwall. Confirm your size preference and construction first, since speed ratings can vary within some sizes.
Radial Tires
Coker Classic Star Series | 2.25 Inch Whitewall | 195/75R14
These answers focus on the wide spread of 1978 Oldsmobile sizes, the mix of radial and bias-ply applications, sidewall choices for Cutlass and Omega fitments, and the practical checks collector-car owners should make before putting an older Oldsmobile back on the road.
Size Basics & Fitment
What tire sizes fit 1978 Oldsmobile vehicles?
1978 Oldsmobile vehicles use 12 different tire sizes across seven model lines: HR78-15 for Custom Cruiser; 195/75R14, 205/70R14, and 185/75R14 for Cutlass; FR78-15 and GR78-15 for Delta 88; GR78-15 and HR78-15 for Ninety-Eight; E78-14, ER78-14, and FR78-15 for Omega; A78-13, B78-13, and BR70-13 for Starfire; and JR78-15 for Toronado. Rim diameters span 13, 14, and 15 inches depending on model and application.
That means year and make alone are not enough to choose correctly on a 1978 Oldsmobile. Start by identifying the exact model, then match the size family and wheel diameter before looking at sidewall style or brand. If your car is an Omega or Starfire, pay especially close attention because those models cross between older bias-ply conventions and radial-era fitments.
What does HR78-15 mean on a 1978 Oldsmobile tire?
HR78-15 is an alphanumeric radial size used on 1978 Oldsmobile Custom Cruiser and Ninety-Eight models. The R in the middle identifies it as a radial tire, and the 15 at the end is the wheel diameter in inches. The H and 78 portions belong to the older alphanumeric sizing system that predates modern metric markings and indicates the tire’s relative section class and profile.
That code matters because HR78-15 is not interchangeable by name with a 14-inch or 13-inch Oldsmobile fitment, and it is not a universal 1978 Oldsmobile size. Buyers restoring a large wagon or luxury sedan often encounter these older radial codes, so it helps to match the exact sidewall marking already on the car or verify the original application through the owner’s manual or marque references.
Do all 1978 Oldsmobile models use the same tire size?
No. 1978 Oldsmobile models use different sizes depending on the model, with compact, midsize, full-size, wagon, and personal-luxury applications all separating into their own size groups. Starfire uses 13-inch sizes, several Cutlass and Omega applications use 14-inch sizes, and larger Delta 88, Ninety-Eight, Custom Cruiser, and Toronado applications rely on 15-inch sizes.
The practical takeaway is simple: identify the model before anything else. A Cutlass owner comparing whitewall radial options is shopping in a very different range from a Toronado owner, even though both wear Oldsmobile badges and come from the same model year. Once the model is confirmed, the choice becomes much easier because the eligible size family narrows quickly.
Buying the Right Tire
Should I choose the E78-14 or the ER78-14 for my 1978 Oldsmobile?
That choice applies to certain 1978 Oldsmobile Omega applications, and the main difference is construction. E78-14 is a bias-ply size, while ER78-14 is a radial size using the same older alphanumeric naming style. Bias-ply tires preserve the period driving feel and visual character many restorers want, while radial construction follows the later-1970s move toward more relaxed road manners and everyday usability.
Choose the tire that matches your goal for the car before drilling down into brand or sidewall details. If the Omega is being restored with originality in mind, the bias-ply route is often the closer visual and historical fit. If the car will be driven more regularly and you want to stay within a period-style radial format, ER78-14 is the more natural path, provided the wheel and application are confirmed first.
What sidewall styles are available for 1978 Oldsmobile tires?
Sidewall choices vary quite a bit across the 1978 Oldsmobile range. Cutlass radial sizes include narrow whitewall, wide whitewall, RWL, redline, and dual-redline options depending on size, while Omega’s E78-14 appears in wide whitewall and blackwall form. That spread reflects how 1978 Oldsmobile covered everything from everyday family transportation to sportier and more upscale trim themes.
For a more factory-looking late-1970s presentation, whitewall styles are often the closest visual direction on mainstream Oldsmobile models, especially larger sedans and many Cutlass applications. Redline, dual-redline, or raised white letter sidewalls create a more performance-oriented look that can suit certain personal tastes, but owners pursuing show-level authenticity should compare sidewall style carefully against the original market presentation of their exact model.
What brands make tires for 1978 Oldsmobile vehicles?
1978 Oldsmobile fitments are covered by several brands across the sizes with current product coverage. Coker Classic, Tornel, and Maxxis appear in 195/75R14; Maxxis and BFGoodrich cover 205/70R14; Tornel, Maxxis, and Travelstar cover 185/75R14; and Coker Classic with STA cover E78-14. Those options span both radial and bias-ply construction, along with everything from whitewalls to blackwalls and performance-style sidewalls.
Brand choice usually comes after the bigger fitment questions are settled. Once the correct size is confirmed, compare sidewall look, construction type, rim-width compatibility, and any speed-rating marking that appears on the exact product you are considering. That approach keeps the decision focused on how the tire will serve your Oldsmobile rather than choosing a brand first and trying to force a fitment afterward.
Fitting & Setup
What rim width do 1978 Oldsmobile tires require?
Rim-width guidance varies by size. For 195/75R14, the range runs from 5.00 to 7.00 inches on some products, with another radial covering 5.00 to 6.50 inches. For 205/70R14, some products fit 5.00 to 7.00-inch rims while others fit 5.50 to 7.50 inches. For 185/75R14, the fitment range spans 4.50 to 7.50 inches depending on product, including a 5J application. E78-14 bias-ply products cover 4.50 to 7.00 inches on one version and 5.0 to 6.0 inches on another.
That variation is why wheel measurement matters even when the sidewall size looks correct. Before choosing a tire, confirm the wheel width on the car and compare it to the exact product’s approved range, not just the size family in general. This is especially important on Cutlass and Omega applications, where multiple tires within the same nominal size category can have different wheel-width allowances.
Do 1978 Oldsmobile tires require inner tubes?
Tube requirements are not universal across 1978 Oldsmobile sizes. The E78-14 fitment includes an STA Traxion version marked tubeless, while other E78-14 products do not use the same wording. The 195/75R14, 205/70R14, and 185/75R14 products shown here use modern radial-style sizing with no tube-type marking in the size field, which generally points buyers toward tubeless-type applications when paired with compatible wheels.
The right way to handle this is to confirm the exact tire marking and the wheel’s construction together, rather than assuming every tire in a size family uses the same setup. If your Oldsmobile still wears original wheels, inspect the wheel condition, valve-stem area, and bead surfaces before mounting any new tire. That extra step matters most on older collector cars that may have seen many decades of service.
Can the original 1978 Oldsmobile wheels be used with all tire sizes?
Original 1978 Oldsmobile wheels can only be used with tire sizes that share the same rim diameter as the wheels already on the car. Starfire applications use 13-inch sizes, several Cutlass and Omega applications use 14-inch sizes, and many larger Oldsmobile models use 15-inch sizes. A 15-inch Toronado or Ninety-Eight wheel is not a match for a 14-inch Cutlass tire, even if both are from the same model year.
After diameter is confirmed, wheel width is the next checkpoint. Some 14-inch products allow a broad width range, while others are more restrictive, so an original wheel should be measured rather than assumed correct. That keeps the setup faithful to the car and avoids problems with bead seating, sidewall shape, or appearance once the tire is mounted.
Maintenance, Storage & Longevity
How should I store a 1978 Oldsmobile when the tires are fitted?
A stored 1978 Oldsmobile should be kept away from direct sunlight, standing moisture, and ozone sources such as electric motors, battery chargers, welders, and running compressors. Clean, dry storage helps any collector tire, but bias-ply fitments such as E78-14, A78-13, and B78-13 tend to develop flat-spotting more readily during long static periods than radial tires. Maintaining correct inflation while the car sits is just as important as the storage environment itself.
If the car will remain parked for long stretches, move it periodically or support it in a way that reduces long-term stress on one contact patch. A quick monthly inspection for pressure loss, sidewall checking, and valve-stem condition can prevent a small issue from becoming a replacement event. Owners who alternate between show use and storage should make that inspection part of every return-to-road routine.
How long do tires on a 1978 Oldsmobile typically last?
On a 1978 Oldsmobile, tire age matters more than mileage in most collector use. A common rule is to begin evaluating tires closely once they are about five to seven years old and to consider replacement as they approach roughly ten years, even if tread depth still looks healthy. The DOT date code on the sidewall is the best way to determine age when present on the exact tire.
Classic cars often see short drives, long storage periods, and changing temperatures, all of which can age a tire without wearing it out in the usual sense. Cracking, hardening, flat-spotting, and slow loss of air are stronger warning signs than tread alone on an older Oldsmobile. If the car has sat for years, inspect age and condition before trusting the tires for regular road use.
How often should tires on a 1978 Oldsmobile be inspected?
Tires on a 1978 Oldsmobile should be checked before every drive and inspected more carefully before any extended outing. Look for sidewall cracking, bulges, punctures, uneven wear, and pressure loss, and make sure the spare is still usable if the car carries one. Any bias-ply fitment deserves extra attention after storage because shape changes can be more noticeable when the car first goes back into service.
A few minutes in the garage can prevent the most common roadside problems. If your Oldsmobile uses a tube-type or tube-sensitive setup, include valve stems and slow-leak behavior in the inspection routine as well. A longer trip is also a good reason to recheck pressures after the tires have cooled overnight, rather than relying on a visual glance alone.
Restoration & Authenticity
What tires were originally fitted to the 1978 Oldsmobile Cutlass?
The 1978 Oldsmobile Cutlass used radial-size applications such as 195/75R14, 205/70R14, and 185/75R14, which fits the broader late-1970s industry shift toward radial tires on mainstream American cars. Sidewall appearance could vary by trim presentation and market preference, with whitewall treatments especially common on everyday and upscale cars of the period. A specific original brand should be confirmed against surviving factory paperwork or period literature for the exact car.
For most restorations, matching the size family and sidewall style is the first priority, followed by choosing a tread and construction that reflects how the car would have appeared when new. If the goal is show judging, compare your car’s surviving evidence, original sales materials, and club guidance before final selection. That is especially helpful on Cutlass variants, where trim character could influence the most authentic visual choice.
Does correct tire fitment matter for showing a 1978 Oldsmobile?
Correct tire fitment matters on a shown 1978 Oldsmobile because judges and knowledgeable enthusiasts often notice size family, construction type, and sidewall style before they notice finer chassis details. A Starfire wearing an obviously different radial profile than its period fitment, or an Omega presented with a sidewall style that clashes with its restoration goal, can look out of step even if the tire physically mounts and drives acceptably.
Owners preparing for judged events should treat tire choice as part of the restoration, not an afterthought. The best approach is to align the car’s tire size, construction, and sidewall look with the exact standard of the event, then verify those details through Oldsmobile clubs, factory literature, and marque specialists. That extra effort often makes the difference between broadly correct and truly convincing.
What is the difference between the BFGoodrich Radial T/A and BFGoodrich Silvertown Radial for a 1978 Oldsmobile?
Within the 205/70R14 fitment used on some 1978 Oldsmobile Cutlass applications, BFGoodrich offers distinct sidewall presentations. Radial T/A uses raised white letters and carries an S speed rating with a 112 mph ceiling, while Silvertown Radial versions appear with redline or dual-redline sidewalls. Rim-width guidance also differs, with the Radial T/A covering 5.00 to 7.00 inches and the Silvertown Radial versions covering 5.50 to 7.50 inches.
That makes the choice more about style and wheel compatibility than simple brand preference. A buyer chasing late-1970s sporty visual impact may prefer raised white letters or redlines, while a buyer with a narrower original wheel should confirm the approved width before committing to one version over the other. Both stay within the same 205/70R14 size family, but they do not serve exactly the same presentation goals.
Safety & Road Use
Are 1978 Oldsmobile tires safe for highway driving?
1978 Oldsmobile tires can be suitable for highway use when the correct size, load capability, and condition are matched to the vehicle. Some 205/70R14 and 185/75R14 products carry an S speed rating, which corresponds to a 112 mph ceiling, while other sizes in this year and make do not show a speed letter in the size marking here. In normal collector use, the mechanical condition of a late-1970s Oldsmobile often matters just as much as the tire’s speed capability.
Safety comes from the complete package: fresh rubber, correct inflation, sound wheels, healthy suspension, and predictable braking. A forty-plus-year-old car should be evaluated as a system before extended highway travel, especially if it has been sitting. If your Oldsmobile still uses a bias-ply fitment, expect a different feel on grooved pavement and in crosswinds than you would from a modern passenger-car radial.
What inflation pressure should I use for 1978 Oldsmobile tires?
Inflation pressure on a 1978 Oldsmobile depends on the exact tire size and product. Examples include 195/75R14 products rated from 1,399 pounds at 35 psi to 1,521 pounds at 32 psi, 205/70R14 products at 1,433 pounds at 35 psi, 185/75R14 products from 1,279 pounds at 35 psi to 1,280 pounds at 44 psi, and E78-14 versions at 1,400 pounds at 32 psi or as high as 1,710 pounds at 60 psi in certain applications.
Those figures are tire ratings, not blanket vehicle recommendations. Use the Oldsmobile owner’s manual or factory placard as the baseline for vehicle pressure, then compare that to the exact tire manufacturer’s guidance for the product you have chosen. Do not transfer an inflation number from one size to another, because the tire’s construction, load range, and intended service can change significantly.
What should I check before taking a 1978 Oldsmobile on a longer drive?
Before a longer drive in a 1978 Oldsmobile, inspect each tire for sidewall cracks, weather checking, cuts, bulges, embedded objects, irregular wear, and pressure loss. Check the spare as well, along with valve stems and any wheel condition issues that could affect air retention. If the car has older bias-ply tires or has been sitting, give it a short local test drive first to detect vibration, flat-spotting, or pull.
Tires are only one part of the preparation on a car from this era. It is equally wise to confirm brakes, cooling system, belts, hoses, steering response, and wheel-bearing condition before committing to a longer trip. That broader inspection is especially important on a full-size Oldsmobile, where the vehicle’s weight and age make every mechanical system work together under sustained road use.
