AC Grayhound Tires

AC Grayhound fitments in this year range use two tire sizes: 640-15 and 670-15. Both sizes are listed for 1963, 1964, 1965, and 1966, and both use a 15-inch rim diameter. The 640-15 products generally fit rims from about 4.00 to 5.00 inches wide, while 670-15 products span roughly 4.00 to 6.00 inches wide depending on the specific tire.

That means year alone does not settle the choice on an AC Grayhound. The practical step is to confirm the tire size already on the car, then compare the wheel width to the listed range for the replacement tire. If the car is being restored, period photos, factory literature, and marque-club knowledge can help determine whether the narrower or wider fitment is more appropriate for the specific car.

A 640-15 size on an AC Grayhound is a traditional numeric bias-ply designation. The 640 means a nominal 6.40-inch section width with the decimal omitted, and the 15 identifies the rim diameter in inches. On the available products, that size is paired with 15-inch wheels and typically suits rims around 4.00 to 5.00 inches wide.

Modern buyers sometimes expect a metric-style code, but AC Grayhound uses an older sizing language tied to period bias-ply construction. Reading the code correctly helps prevent choosing a tire that is too wide for the wheel or changes the car’s stance more than intended. If your Grayhound still wears original-style wheels, matching the numeric size and the listed rim-width range is the best starting point.

A 1963 AC Grayhound has both 640-15 and 670-15 listed because more than one size was used within the model range in the same year. The split is not a wheel-diameter change, since both sizes are for 15-inch rims, and it is not a construction split either because the available products are all bias-ply. The overlap points to a same-year configuration difference within the Grayhound range.

For an owner, that means the right answer comes from the individual car rather than the calendar year alone. Check the wheel width, inspect the size stamped on the current tire if it is known to be correct, and compare the overall look you are trying to preserve. A narrower 640-15 and a wider 670-15 can both be period-appropriate, but they should match the wheel and the restoration goal.

AC Grayhound tire listings in these sizes are bias-ply numeric sizes, and the available product range is entirely bias-ply. For those traditional bias-ply applications, a tube is required. That applies to both 640-15 and 670-15 fitments in the current selection.

Inner tubes are not a minor detail on a collector car like an AC Grayhound. The tube, flap arrangement where applicable, and the condition of the wheel all influence how well the tire performs and holds air in low-mileage use. When replacing tires, inspect the inside of the wheel for rust, burrs, or old tape, because a new bias-ply tire deserves a sound tube-ready wheel environment.

A 1965 AC Grayhound can use either 640-15 or 670-15, so the first job is identifying what your specific car carries. Both sizes are 15-inch fitments, but they suit different wheel-width ranges and create a different visual footprint. The most reliable clues are the size on the existing tire if it has been correct for years, the width of the wheel, and period reference material for the exact car.

Start at the wheel, not the catalog. Measure the wheel width, compare it to the product’s accepted rim range, and then decide whether you are preserving an established setup or returning the car to a more original look. If the car has passed through several owners, do not assume the tires currently mounted are automatically correct simply because they fit the wheel opening.

AC Grayhound tires are available in blackwall, narrow whitewall, and wide whitewall styles. Both 640-15 and 670-15 have blackwall options, while the whitewall choices vary by brand and include several narrow and wide treatments. The available series include traditional American-style bias-ply lines as well as specialty vintage offerings, giving the Grayhound owner a broad visual range within period-style construction.

The right sidewall for an AC Grayhound depends on the look you want as much as the size itself. Blackwalls often suit a more understated sporting presentation, while whitewalls can lean more formal and emphasize the touring character of the car. If the goal is restoration accuracy, compare the sidewall treatment to period photos of your car or to long-term ownership history before making the final call.

AC Grayhound tires in these sizes come from BFGoodrich, Firestone, Avon, Excelsior, US Royal, Coker Classic, Universal Vintage Tire, Goodyear, and STA. The brand spread is broader in 670-15, while 640-15 also includes multiple established vintage-tire names. All of the listed AC Grayhound options remain within bias-ply construction, but they differ in series, sidewall style, and wheel-width suitability.

Brand choice on an AC Grayhound is often about balancing appearance, historical flavor, and how closely you want the car to resemble a period road car. One owner may favor an American wide-whitewall presentation, while another may prefer a blackwall sporting look or an Avon crossply. Once the size is settled, comparing brands by sidewall style and series is usually the most useful next step.

AC Grayhound tire series include Silvertown Classic Bias Ply, Firestone Classic Bias Ply, Super Safety Crossply, Excelsior Bias Ply, US Royal Classic Bias Ply, Coker Classic Bias Ply, Universal Classic Bias Ply, Turbospeed Mk4, Super Cushion, Custom Super Cushion, Super Cushion Deluxe, and Super Transport. Most are passenger-car bias-ply lines, while some represent distinct period tread families or more specialized uses. Super Transport stands apart as a Military & Truck attribute tire in 670-15, which places it outside the more typical Grayhound passenger-car presentation.

For most AC Grayhound owners, the practical comparison is not only brand to brand but series to series. A classic passenger-car bias-ply line usually makes the most sense for a restoration or touring-style presentation, while a specialty truck-oriented series should be chosen only with a clear reason. Once size is fixed, compare sidewall treatment, wheel-width compatibility, and whether the series suits the character you want the car to project.

An AC Grayhound should be stored in a cool, dry, dark space with the tires kept away from direct sunlight, electric motors, welders, ozone sources, and standing moisture. Bias-ply tires also benefit from being kept at their proper inflation pressure during storage so the casing does not sit underinflated for long periods. If the car will remain parked for months, moving it occasionally helps avoid one tire carrying the same load in the same spot.

Collector cars tend to age tires by time and environment more than by mileage. Keeping an AC Grayhound clean, properly inflated, and out of harsh light does more for tire life than many owners realize. If the car is stored long term, some owners also use cradles or take weight off the tires periodically, especially when preserving a fresh concours-oriented set.

Tires on an AC Grayhound should be inspected before each drive and given a more thorough check several times through the driving season. A proper inspection includes inflation pressure, visible sidewall cracking, tread condition, valve stem condition, irregular wear, and any signs that the tire has shifted on the rim. Because the Grayhound uses bias-ply tires, even small visual changes deserve attention before road use.

The key is consistency rather than mileage. Many collector cars cover few miles, so a tire can look acceptable at a glance while quietly aging or developing issues from storage, heat cycles, or low pressure. If an AC Grayhound has been sitting, the first outing of the season should include a careful inspection of all five tires if a spare is carried, not just the four on the ground.

Tires on an AC Grayhound should be replaced when age, cracking, casing condition, repeated air loss, impact damage, or long-term storage deterioration make them questionable, even if the tread still looks deep. Collector-car tires often age out before they wear out. Bias-ply tires especially deserve replacement when the rubber hardens, the sidewalls show checking, or the car develops vibration that cannot be traced to balance alone.

Tread depth by itself is a poor guide on a low-mileage AC Grayhound. A car that attends shows and occasional drives can still be riding on old rubber that no longer has the resilience it once had. Build tire replacement into the car’s long-term maintenance planning, and treat age as seriously as wear, because a handsome vintage tire is not necessarily a healthy one.

AC Grayhound is associated here with 640-15 and 670-15 bias-ply tires on 15-inch rims. The available replacement range includes several classic bias-ply series rather than one single original-equipment pattern, and both blackwall and whitewall styles are represented. That tells the restorer that more than one period-style presentation can be appropriate within the Grayhound family.

For a specific AC Grayhound, originality should be settled with period photographs, ownership history, surviving paperwork, and marque expertise. The main restoration choice is not simply a brand name but the combination of size, sidewall treatment, and overall appearance. Once those are established, selecting a matching bias-ply series becomes much easier and keeps the car visually coherent.

Correct tire fitment can absolutely affect how an AC Grayhound is judged and how seriously the restoration is taken. Size, sidewall style, and overall period look all contribute to whether the car reads as properly finished. Even when the tire physically fits, a mismatch in width or sidewall treatment can change the car’s stance enough to stand out to informed observers.

That matters most on rare, coachbuilt, and enthusiast-known cars such as the AC Grayhound, where details are part of the car’s appeal. Owners pursuing judged events should compare the tire choice to period images and consult AC specialists or club resources. A tire that complements the wheel width and the car’s original character can support both presentation and long-term value.

AC Grayhound tire choices include blackwall, narrow whitewall, and wide whitewall styles, so more than one restoration direction is possible. Blackwall can suit a more sporting British GT appearance, while narrow or wide whitewall options create a more formal period touring look. Since both 640-15 and 670-15 have style variation, sidewall correctness depends on the history and presentation of the individual car.

The right answer for an AC Grayhound restoration usually comes from period photographs, long-term family ownership evidence, or a clear vision for the era-specific look you want to preserve. Sidewall style changes the personality of the car almost as much as the wheel itself. Once you know whether the car should read as sporting, elegant, or concours-authentic, the sidewall choice becomes far more obvious.

A properly selected, correctly mounted, and well-maintained set of AC Grayhound bias-ply tires can be suitable for normal collector-car road use. The important point is that the tire must match the wheel size and width, be in sound condition, and be used within the expectations of a mid-1960s grand touring car rather than a modern performance car. Bias-ply tires deliver a distinctly period driving feel and should be treated that way.

Safety on an AC Grayhound depends on the whole package, not the tire alone. Wheel condition, tube condition, suspension health, steering accuracy, and alignment all play a role in how stable the car feels on the road. If the car is newly acquired or recently awakened from storage, give the chassis and tires a full inspection before asking it to do regular road miles.

Before driving an AC Grayhound, check tire inflation, look for sidewall cracks or cuts, inspect tread for embedded damage, and confirm that each tire is seated properly on the rim. Because the Grayhound uses period-style bias-ply fitments, you should also pay attention to how long the car has been sitting and whether any tire shows a flat-spotted feel at the first few revolutions. A quick visual inspection is useful, but a hands-on pressure check matters more.

Beyond the tires, an AC Grayhound should be treated as a collector car that rewards a pre-drive routine. Verify that the spare is serviceable, make sure the jack and tools are present, and note any fresh vibration, pull, or steering wander as soon as the car moves. Catching a small tire issue in the garage is far easier than diagnosing it at speed.

An AC Grayhound on period-style bias-ply tires should be driven at sensible collector-car speeds, with the car’s age, tire condition, road surface, and weather all taken seriously. Even though the Grayhound is a capable grand tourer, original-style bias-ply tires do not behave like modern radials in lane changes, braking, or sustained high-speed running. Mechanical condition and careful preparation matter just as much as the printed size on the sidewall.

The practical approach is to build speed gradually and let the car tell you how settled it feels. If the steering is nervous, the tires are old, or the road is hot and rough, back the pace down. A well-sorted AC Grayhound is enjoyable at moderate touring speeds, and preserving the car often means resisting the temptation to ask vintage-style tires to perform like contemporary high-speed rubber.