The 1966 Buick Wildcat belongs to Buick’s big-cube, full-size performance era, when personal luxury and strong straight-line power often shared the same showroom floor. Its long, substantial stance looks right on tall 15-inch bias-ply tires, and that matters when the goal is to preserve the car’s proper visual balance. For this model, the key fitment decision is between 8.45-15 and 8.85-15, both in bias-ply construction. That makes the conversation less about switching construction and more about confirming which size suits the car’s exact setup. Owners focused on restoration appearance or road use should start by verifying wheel size, tire size, and overall clearance before choosing.
Which Tire Size Is Right for The 1966 Buick Wildcat
The 1966 Buick Wildcat uses two primary tire sizes, both in bias-ply construction on 15-inch rims. Because the same covered sub-model can be associated with either 8.45-15 or 8.85-15, the first step is confirming which size is on the car now and whether the wheel and overall vehicle setup match that fitment before selecting a replacement.
In an 8.45-15 size, the first number refers to the tire’s nominal section width in inches, while the final number identifies a 15-inch rim. This is a bias-ply tire format, which suits the 1966 Buick Wildcat’s original-era fitment character and preserves the tall-sidewall look associated with full-size American cars of the period. Buyers considering this size should think in terms of maintaining a traditional driving feel and visual presentation rather than changing construction. It is a useful choice when the car’s current wheel setup and clearance are already centered around the narrower of the two Wildcat tire sizes.
An 8.85-15 tire uses the same numeric bias-ply sizing system, with 8.85 indicating a nominal section width and 15 indicating rim diameter in inches. Like 8.45-15, it keeps the 1966 Buick Wildcat in its proper bias-ply construction family and supports a period-style tire profile on a 15-inch wheel. The practical distinction is that this is the wider of the two primary Wildcat sizes, so it should be matched to the car’s actual wheel and body clearance. Confirming the existing wheel and current tire size is especially important before moving to this fitment.
Fitment for the covered 1966 Buick Wildcat sub-model is straightforward in one sense and selective in another. The Wildcat Base can use either of the two primary bias-ply sizes, so checking the exact tire already on the car and confirming wheel setup still matters before replacement.
1
1966 Buick Wildcat Base
The 1966 Buick Wildcat Base is associated with both 8.45-15 and 8.85-15 bias-ply tire sizes on 15-inch rims. That means tire selection starts with confirming which size the car is actually set up to use, then choosing a replacement that matches the intended period-style appearance and available clearance.
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.
Frequently Asked Questions
These 1966 Buick Wildcat tire FAQs focus on the two primary bias-ply sizes, 15-inch rim fitment, selection factors for a big Buick, restoration-minded appearance, and the checks worth making before putting a collector car back on the road.
Tire Size & Fitment
What tire size fits a 1966 Buick Wildcat?
A 1966 Buick Wildcat uses one of two primary tire sizes: 8.45-15 or 8.85-15. Both are bias-ply sizes designed for 15-inch rims, and both are associated with this exact year and model. The Wildcat Base can be found with either size, so there is not just one universal answer without checking the car’s current setup.
The practical step is to confirm which size is already on the vehicle and whether the wheel diameter remains 15 inches. On a collector car, wheels may have been changed over time, so matching the replacement tire to the actual wheel and available clearance is more useful than assuming every 1966 Wildcat is running the same size today.
What size rim does a 1966 Buick Wildcat use?
The primary tire fitments for a 1966 Buick Wildcat are built around a 15-inch rim diameter. Both 8.45-15 and 8.85-15 use that same 15-inch wheel diameter, which simplifies the basic rim question even though the model can use two different tire widths.
Rim diameter is only the first checkpoint. Before choosing a tire, it still makes sense to confirm the wheel itself has not been replaced with an aftermarket version that changes width or offset, because those details can affect how either Wildcat tire size sits in the wheel opening and how much clearance remains at steering and suspension points.
Why does the 1966 Buick Wildcat have more than one tire size?
The 1966 Buick Wildcat is associated with both 8.45-15 and 8.85-15, so more than one primary fitment exists for this model. Both sizes stay within the same basic bias-ply, 15-inch-wheel family, but they represent different tire widths rather than different construction types or different rim diameters.
That means the decision is not between bias-ply and radial as a primary fitment, but between two period-style size choices. A buyer should identify which size the car is already using, then verify wheel dimensions and body clearance before changing widths. That approach helps avoid selecting a tire that is correct for the model family but not for the specific Wildcat in front of you.
Choosing the Right Tire
What should I consider when choosing a 1966 Buick Wildcat tire?
Start with the basics: the 1966 Buick Wildcat uses bias-ply tires in either 8.45-15 or 8.85-15, both on 15-inch rims. The first choice is confirming the correct size for the car’s present wheel setup. After that, the main consideration is whether the goal is a traditional period-style look and feel that stays true to the Wildcat’s original-era tire construction.
A wider tire is not automatically the better choice, and a narrower one is not automatically more correct for every car. Check the wheel diameter, verify the size already fitted, and look closely at fender and suspension clearance. On a full-size Buick, those small confirmation steps matter more than making assumptions based only on the model name.
How do I choose between the available 8.45-15 and 8.85-15 tires for a 1966 Buick Wildcat?
The choice between 8.45-15 and 8.85-15 comes down to matching the tire to the Wildcat’s actual setup. Both are primary bias-ply fitments for a 1966 Buick Wildcat and both use a 15-inch rim, but 8.85-15 is the wider size. That makes wheel fit and available clearance important considerations rather than afterthoughts.
A sensible approach is to inspect the tire currently on the car, confirm the wheel diameter, and avoid changing widths unless the rest of the setup supports it. If the car has been altered over the years, a current measurement matters more than assumptions. The right choice is the size that aligns with the vehicle’s wheel, stance, and intended use.
What rim-fitment details should I compare when choosing 1966 Buick Wildcat tires?
For a 1966 Buick Wildcat, the key rim-fitment point is 15-inch diameter, since both 8.45-15 and 8.85-15 are built for that wheel size. Diameter alone is not the whole story, though. A tire can match the rim diameter and still create problems if the wheel width or overall wheel position on the car differs from what the tire size expects.
It helps to inspect the wheel itself, especially on a collector car that may no longer have its original wheel package. Compare the tire size already fitted, look for any signs of tight sidewall or fender clearance, and verify there is no rubbing through the steering range. Those checks are particularly worthwhile before moving from 8.45-15 to 8.85-15.
Restoration & Appearance
Which tire should I choose for a period-style 1966 Buick Wildcat?
A period-style 1966 Buick Wildcat tire choice starts with the two primary bias-ply sizes: 8.45-15 and 8.85-15. Staying within those original-era sizing conventions preserves the tall-sidewall look that suits a full-size mid-1960s Buick. The right selection depends on which size the car is already set up to use rather than on a one-size-fits-all restoration assumption.
For many owners, the visual goal is preserving the Wildcat’s proper stance and overall character. That makes it worth checking old photos, marque references, or vehicle-specific restoration records if exact presentation matters. Even when a period-style look is the priority, wheel diameter, clearance, and the size already fitted should still guide the final choice.
Does correct tire fitment matter for a 1966 Buick Wildcat restoration?
Correct tire fitment matters on a 1966 Buick Wildcat restoration because tire size strongly affects the way the car sits and how authentic the overall presentation feels. Using one of the two proper bias-ply sizes, 8.45-15 or 8.85-15, keeps the restoration grounded in the right tire era and avoids a visibly mismatched modern look.
Fitment also affects practicality, not just appearance. A restoration-minded tire should suit the wheel diameter, clear the body and suspension, and maintain the car’s intended stance. If originality is the goal, confirm the existing wheel and compare it with the car’s known setup before ordering tires, especially when the Wildcat has changed hands or been modified over time.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1966 Buick Wildcat?
Yes, modifications can affect tire fitment on a 1966 Buick Wildcat even when the tire remains within one of the proper sizes. The model uses 8.45-15 or 8.85-15 bias-ply tires on 15-inch rims, but aftermarket wheels, altered ride height, suspension changes, or body work can change how much space is available around the tire.
A Wildcat that has been lowered, fitted with different wheels, or changed at the front suspension may not behave like an untouched car. Check clearance at the fender edge, inner wheelhouse, and steering range before settling on a replacement. That is especially important when moving to the wider 8.85-15 size on a car with an unknown modification history.
What should I inspect before driving a 1966 Buick Wildcat on new tires?
Before driving a 1966 Buick Wildcat on new tires, inspect the wheels, valve stems, and the overall condition of the suspension and steering components. Make sure the car is wearing the correct 15-inch wheel diameter for its 8.45-15 or 8.85-15 bias-ply tires, and confirm there is no interference at full steering lock or over suspension travel.
It also helps to look beyond the new tires themselves. Check alignment behavior, watch for uneven ride height, and inspect nearby brake and suspension parts for looseness or wear that could affect tire wear or clearance. On an older full-size Buick, those supporting systems influence how the new tires perform just as much as the tire size does.
How should 8.45-15 or 8.85-15 tires on a collector 1966 Buick Wildcat be maintained?
Collector-car tires on a 1966 Buick Wildcat should be checked regularly for air loss, cracking, cuts, bulges, and uneven tread wear, even if the car is driven only occasionally. That applies whether the car uses 8.45-15 or 8.85-15 bias-ply tires. Low annual mileage does not prevent age-related deterioration, especially on a large, heavy vehicle.
Storage habits matter as much as mileage. Keep the Wildcat away from prolonged heat, direct sunlight, moisture, and ozone sources, and inspect the tires before longer drives after the car has been sitting. A careful walkaround, a pressure check, and a quick look at wheel and suspension condition can prevent small storage-related issues from becoming road-use problems.
