The 1968 Buick Wildcat came from an era when Buick still gave its full-size personal-performance cars real road presence, with big proportions, strong V8 character, and styling that looked substantial from every angle. That kind of car depends heavily on tire stance, because the tire fills so much of the visual and driving personality. For the 1968 Buick Wildcat, the primary fitments are 8.45-15 and 8.85-15, both traditional bias-ply sizes on 15-inch rims. Tire selection here is less about modern upsizing and more about choosing the right numeric bias-ply size for the car's wheel setup and the look you want to preserve.
Which Tire Size Is Right for The 1968 Buick Wildcat
The 1968 Buick Wildcat uses two primary tire sizes, both in bias-ply construction and both built for 15-inch rims. Because the Base model can be found with either 8.45-15 or 8.85-15, the first step is confirming which size is already on the car or which wheel and stance combination the vehicle is set up to use before choosing a replacement.
An 8.45-15 uses the older numeric bias-ply sizing system, where 8.45 refers to the nominal section width in inches and 15 identifies the wheel diameter. On a 1968 Buick Wildcat, this size keeps the car in a traditional full-size bias-ply format that suits restoration-oriented replacements and period-style road use. Numeric bias-ply sizing is familiar to collector-car owners because it reflects the tire conventions used on many American cars of the era. This size is worth evaluating when the car retains its original-style wheel setup and you want to stay close to the traditional tire presentation.
An 8.85-15 follows the same numeric bias-ply system, with a nominal section width of 8.85 inches and a 15-inch rim diameter. For the 1968 Buick Wildcat, it represents a second traditional full-size bias-ply fitment rather than a modern substitute, so correct selection depends on the wheel and vehicle setup already in place. This format is especially relevant to buyers trying to maintain the broad-shouldered appearance expected from a late-1960s Buick. It should be considered only after confirming the car is using the wider primary size and has the wheel clearance to match.
Sub-model fitment is straightforward here, but size selection still matters because the 1968 Buick Wildcat Base can use either of the two primary bias-ply sizes. Checking the exact tire already fitted to the car and confirming the wheel setup will help narrow the right replacement.
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1968 Buick Wildcat Base
The 1968 Buick Wildcat Base uses traditional 15-inch bias-ply fitment and can be found with either 8.45-15 or 8.85-15. That makes tire selection less about trim level differences and more about verifying which of the two primary sizes matches the car's present wheel, clearance, and restoration direction.
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 FAQs focus on the two bias-ply tire sizes used on the 1968 Buick Wildcat, how to confirm the correct 15-inch fitment, and what to inspect before putting a full-size collector Buick back on the road.
Tire Size & Fitment
What tire size fits a 1968 Buick Wildcat?
A 1968 Buick Wildcat uses either 8.45-15 or 8.85-15, and both are traditional bias-ply tire sizes. Those two sizes share the same 15-inch rim diameter, so the key difference is the tire's nominal section width rather than a change in wheel diameter.
Choosing between them starts with confirming what is already fitted to the car, especially on a vehicle that may have been restored, modified, or re-wheeled at some point. Matching the existing wheel setup and checking available clearance around the fenders and suspension is more useful than assuming every Wildcat uses the same width.
What size rim does a 1968 Buick Wildcat use?
The 1968 Buick Wildcat uses a 15-inch rim with its primary tire fitments. Both 8.45-15 and 8.85-15 are built around that same rim diameter, which keeps wheel-diameter identification simple even though two tire widths are associated with the car.
Rim diameter is only one part of the fitment picture, so it is still smart to verify the wheel itself before ordering tires. A collector car may have replacement wheels or later components, and wheel width can influence how comfortably a given bias-ply size sits and clears on the vehicle.
Why does the 1968 Buick Wildcat have more than one tire size?
The 1968 Buick Wildcat is associated with two primary bias-ply sizes, 8.45-15 and 8.85-15. Since both use the same 15-inch rim diameter, the variation centers on tire width rather than an entirely different wheel package.
That means the practical decision is identifying which setup your own car actually uses instead of treating the two sizes as interchangeable by default. On a full-size Buick, even a modest size change can affect visual stance, wheel compatibility, and clearance, so the existing wheel and tire combination should be checked first.
Choosing the Right Tire
What should I consider when choosing a 8.45-15 tire for a 1968 Buick Wildcat?
Start by making sure 8.45-15 is the size the car is actually set up to use, since the 1968 Buick Wildcat can also use 8.85-15. An 8.45-15 is a numeric bias-ply size, so the selection process centers on staying within the correct period-style sizing format and matching the wheel diameter.
Beyond size, think about how the car will be used and how original you want the overall presentation to remain. A Wildcat intended for restoration-oriented display may call for a traditional bias-ply look, while a regularly driven car still needs careful checks for wheel width, clearance, tire condition, and balanced fitment front to rear.
What should I consider when choosing a 8.85-15 tire for a 1968 Buick Wildcat?
An 8.85-15 should be chosen only after confirming that the 1968 Buick Wildcat is using that wider primary bias-ply size rather than 8.45-15. The size follows the older numeric system and keeps the car in a traditional 15-inch collector-car fitment instead of moving into a modern radial sizing format.
Because the Wildcat is a large late-1960s Buick, the wider size can influence stance and available space around the body and chassis more noticeably than a simple rim-diameter change. Checking wheel width, front steering clearance, rear fender room, and overall consistency with the car's intended appearance helps avoid a mismatch.
How do I choose between the available 1968 Buick Wildcat tire sizes?
The decision comes down to whether your 1968 Buick Wildcat is set up for 8.45-15 or 8.85-15, since both are correct primary bias-ply formats for a 15-inch rim. This is not a case of choosing between bias-ply and radial as primary fitments, but of confirming which of the two original-style widths belongs on the car.
A quick comparison of the existing tires, wheel dimensions, and clearance around the car usually answers the question more reliably than appearance alone. The right choice should support the Wildcat's stance, fit the wheel properly, and suit the owner's goals for road use, restoration character, and visual balance.
Restoration & Appearance
Which tire should I choose for a period-style 1968 Buick Wildcat?
A period-style 1968 Buick Wildcat should stay with one of its original-style primary bias-ply sizes, either 8.45-15 or 8.85-15, depending on the wheel and tire setup already on the car. Both sizes preserve the older numeric sizing character that suits a late-1960s full-size Buick.
The better restoration choice is usually the one that matches the car's established stance and wheel fitment rather than simply selecting the wider of the two sizes. If exact historical originality matters, compare the car against marque references, original literature, or restoration records before committing to one presentation.
Does correct tire fitment matter for a 1968 Buick Wildcat restoration?
Correct tire fitment matters on a 1968 Buick Wildcat restoration because the car's size and styling make tire proportions highly visible. Using one of the proper bias-ply 15-inch fitments helps maintain the broad, substantial look that belongs on a full-size Buick of this era.
Fitment also affects more than appearance, since the wrong width can alter clearance and the way the car sits on its wheels. Even on a show-focused restoration, the existing wheel setup should be confirmed so the tire supports both the intended presentation and practical roadworthiness.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1968 Buick Wildcat?
Yes, modifications can affect tire fitment on a 1968 Buick Wildcat even when the car is using one of its correct primary sizes, 8.45-15 or 8.85-15. Changes such as aftermarket wheels, altered ride height, brake conversions, or bodywork can influence how much room the tire has at the fender and suspension.
That is why a modified Wildcat should be measured and inspected rather than matched by year and model alone. Wheel diameter may still be 15 inches, but width, offset, and clearance at full steering lock can all change whether a traditional bias-ply size works comfortably on the car.
What should I inspect before driving a 1968 Buick Wildcat on new tires?
Before driving a 1968 Buick Wildcat on new tires, inspect the wheels for damage, confirm the tire size matches the car's setup, and look over suspension and steering components that could affect tracking or clearance. It is also wise to check for any signs of rubbing points around the wheel openings.
A full-size collector car benefits from a careful walkaround after installation and again after the first short drive. Tire pressure, lug security, visible sidewall condition, and even contact patterns can reveal issues early, especially if the car has sat for long periods or has seen previous wheel changes.
How should 8.45-15 or 8.85-15 tires on a collector 1968 Buick Wildcat be maintained?
Collector-car tires in 8.45-15 or 8.85-15 should be maintained with regular pressure checks, visual inspections, and attention to age-related condition even if tread wear looks minimal. On a 1968 Buick Wildcat, long storage periods can leave tires appearing usable while the sidewalls or carcass have already begun to deteriorate.
Good maintenance also means keeping the car stored away from prolonged sunlight, excess moisture, and ozone sources such as electric motors or battery equipment. A Wildcat that is driven only occasionally still deserves routine inspection for cracking, bulges, cuts, and slow air loss before every meaningful road outing.
