1963 AC Grayhound Tires

The 1963 AC Grayhound uses two primary tire sizes: 640-15 and 670-15. Both are numeric bias-ply sizes designed for 15-inch rims, and the Grayhound Base can appear with either one. That means the correct replacement is not chosen by year and model alone, but by confirming which size is actually fitted to the car.

A Grayhound that has been restored, re-wheeled, or simply re-tired at some point may not still be wearing its previous intended size. Checking the tire sidewall, measuring the wheel diameter, and confirming the wheel width are smart first steps. Once the size is confirmed, the next decision becomes sidewall style, brand, and whether to stay with a traditional bias-ply tire or consider a radial equivalent.

The 1963 AC Grayhound uses a 15-inch rim with both of its primary tire sizes, 640-15 and 670-15. The final number in each size code identifies the rim diameter, so both fitments are built around the same 15-inch wheel diameter even though the tires differ in nominal width.

Wheel diameter is only part of the fitment picture on a collector car. Wheel width still matters, especially when comparing different tire brands, whitewall versions, or radial-equivalent options. It is worth checking the actual wheel before purchase, particularly if the car has replacement wheels, an older restoration, or a mixed set assembled over time rather than one confirmed original-style wheel package.

The 1963 AC Grayhound can use either 640-15 or 670-15, both in bias-ply construction. In practical terms, that means the car is associated with two period-style fitments on the same 15-inch rim diameter. The difference is primarily in the nominal section width, with 670-15 being the wider of the two sizes.

For a buyer, the important takeaway is that the larger size should not be chosen simply because it exists for the model. The right approach is to confirm which size matches the wheels and setup already on the car. That is especially important if the Grayhound has been restored, modified, or fitted with different wheels at some point in its life, because appearance and clearance can change quickly on a low-volume British GT car.

On the 1963 AC Grayhound, 640-15 is a primary bias-ply tire size. It uses the older numeric sizing format common to vintage cars, where the 640 refers to an approximate nominal section width and the 15 refers to the rim diameter. The available primary replacement tires in this size stay within that traditional bias-ply construction.

A radial can still be considered through the equivalent-size route, but that is a separate decision from the original fitment. Buyers keeping a period-style driving feel and presentation often stay with bias-ply construction, especially when choosing among blackwall and whitewall options. Anyone considering a conversion should compare the wheel setup carefully, since radial-equivalent sizing still needs to be checked for rim compatibility and clearance.

Radial equivalents for 670-15 include 195R15 as an 80-series metric radial, P205/75R15 as a 75-series P-metric radial, P215/70R15 as a 70-series P-metric radial, and 670R15 as a bias-look radial. Those choices give the 1963 AC Grayhound owner several ways to compare modern radial sizing conventions with the original numeric bias-ply format.

Each of those sizes should be treated as an alternative to evaluate, not as an automatic interchange. The recommended rim-width range tied to the 670-15 equivalents is 5 to 7 inches, which makes wheel measurement especially important before making a change. It also helps to check steering and body clearance, because the Grayhound's actual wheel and suspension setup may differ from car to car after years of restoration or modification.

A conversion from bias-ply to radial tires on a 1963 AC Grayhound starts with confirming the current primary size, then matching it to the correct radial equivalent. For 640-15, the available radial alternatives are 175R15, P175/75R15, and P185/70R15. For 670-15, the alternatives are 195R15, P205/75R15, P215/70R15, and 670R15 as a bias-look radial.

Wheel width should be checked before anything else, because the published equivalent ranges are 5-6 inches for 640-15 and 5-7 inches for 670-15. After that, compare the chosen tire with the car's available fender, steering, and suspension clearance. A Grayhound with replacement wheels, altered ride height, or older chassis work deserves extra attention before switching construction types, even when the equivalent size looks appropriate on paper.

Start by confirming whether the car actually uses 640-15 or 670-15, since both are associated with the 1963 AC Grayhound and both are 15-inch bias-ply fitments. After that, compare the available tire series, sidewall treatments, and any wheel-width requirements that apply to the tire you are considering. Load figures can also be useful when they are available.

The best choice depends on what matters most for the car's use and presentation. A buyer focused on a traditional look may lean toward a blackwall or whitewall bias-ply in a period-style series, while someone planning more road miles may want to compare radial-equivalent options separately. On an AC of this era, appearance, wheel compatibility, and the actual setup of the individual car all deserve equal attention.

Tires for the 1963 AC Grayhound are available in blackwall, narrow whitewall, and wide whitewall styles. Those sidewall choices appear across both 640-15 and 670-15 fitments, although the broader selection is in 670-15. That gives the Grayhound owner a meaningful range of traditional visual treatments without stepping outside the vehicle's vintage tire character.

Sidewall choice has a strong effect on how the car sits visually, especially on a British grand touring car with elegant proportions. A blackwall tends to look understated and sporting, while narrow and wide whitewalls shift the presentation toward different period-style themes. The decision should be made alongside the tire size already on the car, because appearance only works well when the tire also matches the wheel and overall fitment.

The 1963 AC Grayhound has tire options from several brands, including Firestone, BFGoodrich, Avon, Excelsior, US Royal, Goodyear, Coker Classic, Universal Vintage Tire, and STA. Brand availability depends partly on whether the car uses 640-15 or 670-15, with the larger 670-15 size offering the widest spread of choices and tire series.

Brand should be considered as one part of the decision, not the whole decision. It helps to compare the sidewall style, tire series, wheel-width compatibility, and overall look of each option in the correct size first. On a collector car like the Grayhound, the visual character of the tire can matter as much as the name on the sidewall, especially when matching a restoration theme or preserving a long-established appearance.

A period-style 1963 AC Grayhound starts with the correct primary fitment on a 15-inch rim, which means confirming whether the car uses 640-15 or 670-15 bias-ply tires. From there, the choice usually comes down to a traditional bias-ply series and the sidewall presentation that best suits the car's look, such as blackwall, narrow whitewall, or wide whitewall.

Buyers focused on restoration appearance often begin by matching the tire's visual character to the stance and trim of the individual car rather than chasing the broadest selection. Exact originality claims should be checked against marque references, period photos, and vehicle-specific documentation if that level of detail matters. For many Grayhound owners, a correct-size bias-ply with an appropriate sidewall treatment delivers the right period-style balance.

Tire construction changes more than driving feel on a restored 1963 AC Grayhound; it also changes how the car presents visually. A bias-ply tire keeps the vintage numeric sizing format and traditional look associated with the car's era, while a radial equivalent can alter that presentation even when it remains a reasonable alternative size for road use.

That difference matters most when the Grayhound is being restored with a strong period-style goal. A blackwall or whitewall bias-ply often supports that vintage character more naturally, and a bias-look radial can be worth considering when 670-15 is the starting point. The right choice depends on whether the project puts higher value on appearance continuity, touring convenience, or a compromise between the two.

Modifications can absolutely affect tire fitment on a 1963 AC Grayhound, even though the primary tire sizes are 640-15 and 670-15 on 15-inch rims. Changes such as aftermarket wheels, altered wheel width, suspension work, ride-height adjustments, or body repairs can influence which tire size still works comfortably on the car.

That is why an older restoration should be treated as an individual setup rather than a purely catalog-style fitment exercise. The smart approach is to verify wheel diameter and width first, then check steering lock, fender clearance, and the space around suspension components. Those checks become even more important when comparing a radial equivalent, since equivalent sizing should still be confirmed against the Grayhound's actual configuration.

Before driving a 1963 AC Grayhound on new tires, inspect the wheels for the correct 15-inch diameter, confirm that all four tires match the intended size, and make sure inflation is set appropriately for the tire being used. It is also wise to look over the valve stems, wheel condition, and basic alignment condition before the car returns to regular road use.

A collector car deserves a broader walk-around before its first outing. Check for rubbing at full steering lock, verify that the tires clear the fenders and suspension, and make sure there are no signs of loose steering or worn suspension parts that could affect tire wear. On a low-use GT car, a short test drive followed by another visual inspection is a sensible way to confirm everything is settling properly.

Collector-car tires in 640-15 or 670-15 size should be maintained with regular pressure checks, routine visual inspection, and careful storage habits. Even when tread wear is low, a 1963 AC Grayhound that spends long periods parked still needs attention for cracking, bulges, cuts, flat-spotting, and slow air loss. Those issues matter as much as mileage on an infrequently driven car.

Storage conditions have a real effect on vintage-style tires, so the car should be kept away from prolonged sunlight, excessive heat, moisture, and ozone sources when possible. It also helps to move the car occasionally and inspect the tires before longer drives rather than assuming they are fine because the car has seen little use. That routine is especially important with older collector vehicles that are driven seasonally.