1964 AC Grayhound Tires

The 1964 AC Grayhound is associated with two primary tire sizes: 640-15 and 670-15. Both are bias-ply sizes built for 15-inch rims, so the fitment question is not simply rim diameter but which of those two traditional numeric sizes matches the car’s current wheel and setup.

Since both sizes appear on the same model coverage, the safest next step is to inspect the tires and wheels already on the car rather than assume one size over the other. Wheel width, the stance of the car, and available clearance around the fenders and steering components should all be reviewed before choosing between 640-15 and 670-15.

The 1964 AC Grayhound uses a 15-inch rim with both of its primary tire sizes. That 15-inch rim diameter is shared by 640-15 and 670-15, so either primary fitment starts from the same basic wheel diameter even though the tires differ in nominal section width.

Rim diameter alone does not settle the fitment decision, because wheel width also matters when selecting a replacement tire or considering a radial equivalent. Measuring the actual wheel on the car is worthwhile, especially on a low-production British car that may have seen wheel changes over time or may no longer be wearing its earlier tire setup.

The 1964 AC Grayhound is associated with both 640-15 and 670-15, which means more than one primary bias-ply size can be relevant for this model. In practical terms, that creates a fitment decision around the car’s actual wheel and tire setup rather than a one-size-fits-all replacement path.

Older collector cars are often found with different wheel widths, replacement wheels, or long-standing tire substitutions, so confirming what is on the car matters. Looking at the existing tire size, checking the wheel width, and reviewing clearance at full steering lock will help determine which of the two primary sizes makes the most sense before ordering replacements.

For the 1964 AC Grayhound, 640-15 is a primary bias-ply tire size. It uses the older numeric sizing system common to many vintage vehicles, and in this application it represents a traditional 15-inch fitment rather than a modern radial size designation.

That matters because a buyer choosing 640-15 is usually deciding whether to stay with a period-style bias-ply feel and appearance or move to one of the available radial equivalents. A radial alternative can be considered, but wheel width, overall dimensions, and the car’s available clearance still need to be checked before changing construction.

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 1964 AC Grayhound owner several ways to compare modern radial sizing against the original bias-ply format.

Each equivalent follows a different sizing convention, so the choice is not just radial versus bias-ply but also how closely the tire’s profile and appearance suit the car. The recommended rim-width range for these 670-15 radial equivalents is 5-7 inches, and wheel width plus clearance should be confirmed before making the switch.

A bias-ply to radial change on a 1964 AC Grayhound starts with confirming the original size on the car, then comparing the appropriate radial equivalent for that specific fitment. The main checks are wheel diameter, wheel width, available clearance, and whether the selected radial matches the intended use and presentation of the car.

A 640-15 car can be compared against 175R15, P175/75R15, or P185/70R15, while a 670-15 car can be compared against 195R15, P205/75R15, P215/70R15, or 670R15. Looking at steering clearance, fender space, suspension condition, and the car’s current stance helps avoid treating a radial equivalent as an automatic interchange.

Start with the correct primary size for the car, because the 1964 AC Grayhound is associated with both 640-15 and 670-15. After size is confirmed, the main selection factors are bias-ply construction, wheel compatibility, sidewall style, brand, and the vintage tire series that best suits the car’s appearance and intended use.

A narrower 640-15 and a wider 670-15 should not be chosen by appearance alone. It helps to inspect the current wheel width, review any earlier tire changes, and think about whether the car is being preserved for period-style presentation, regular touring, or a mix of display and road use before narrowing the product choices.

Tires for the 1964 AC Grayhound are available in blackwall, narrow whitewall, and wide whitewall styles, depending on the size and product line. That gives the car owner room to keep a restrained touring look, add a subtle whitewall accent, or choose a more pronounced period-style sidewall presentation.

Sidewall style should be chosen after the correct tire size is settled, not before. A wide whitewall can strongly influence the car’s visual character, while blackwall and narrow whitewall options often suit a more understated look. If historical appearance is important, marque references and period photography can help guide the cosmetic decision.

The 1964 AC Grayhound has tire options from BFGoodrich, Firestone, Avon, Excelsior, US Royal, Goodyear, Universal Vintage Tire, Coker Classic, and STA across its two primary sizes. Those brands appear in a mix of blackwall and whitewall configurations and in several vintage-style bias-ply series.

Brand selection works best when it is treated as part of a larger fitment decision. The correct size, sidewall treatment, and wheel compatibility should be settled first, then the buyer can compare series names, load figures where shown, and visual character within the available brands instead of assuming one label answers every need.

A period-style 1964 AC Grayhound usually starts with the correct primary bias-ply size already suited to the car, either 640-15 or 670-15. From there, the choice becomes one of visual character and intended use, with blackwall, narrow whitewall, and wide whitewall options offering noticeably different vintage presentations.

Owners focused on restoration appearance often stay with bias-ply construction because it preserves a traditional look and era-appropriate sizing style. Since the Grayhound can be associated with two primary sizes, confirming the car’s existing wheel and tire setup is important, and exact originality questions are best checked against marque-specific historical references.

On a restored 1964 AC Grayhound, tire construction can change the visual impression as much as the sidewall style. A bias-ply tire preserves the classic numeric size format and traditional profile associated with the car’s era, while a radial alternative can alter how the tire looks even when chosen as an equivalent.

That does not make one approach universally right, but it does make construction part of the restoration decision rather than just a driving choice. A buyer balancing authenticity cues with road use should look at the car’s stance, wheel width, and desired presentation before deciding whether to keep a bias-ply tire or consider a radial equivalent.

Yes, modifications can affect tire fitment on a 1964 AC Grayhound even when the car is using one of its primary 15-inch tire sizes. Changes to wheel width, wheel offset, suspension height, steering components, or body clearance can all influence how comfortably a 640-15, 670-15, or any radial equivalent sits on the car.

That is especially important on collector vehicles that may have been updated over the years without obvious visual clues. A quick check of wheel dimensions, steering-lock clearance, and fender space can prevent surprises, and it becomes even more important when moving from bias-ply construction to a radial-equivalent tire in either primary size range.

Before driving a 1964 AC Grayhound on new tires, inspect the wheels for correct diameter and condition, confirm the tire size matches the car’s setup, and make sure the tires clear the fenders and steering components. It is also wise to check valve stems, wheel hardware, and the overall condition of the suspension and steering system.

A newly mounted tire should not be treated as the only variable on an older grand touring car. Pressure should be set appropriately for the tire in use, and the car should be driven carefully at first while watching for rubbing, pull, vibration, or uneven behavior that could point to wheel, alignment, or chassis issues.

Collector-car tires in 640-15 or 670-15 size should be maintained with regular pressure checks, visual inspections, and careful storage habits. Even when tread looks fresh, older bias-ply tires can develop cracking, flat spotting, air loss, cuts, or sidewall damage simply from age, inactivity, and long periods of display use.

Routine inspection is especially important before tours or longer drives. Looking at the tread, sidewalls, and bead area, checking for bulges, and keeping the car away from prolonged heat, moisture, sunlight, and ozone-producing equipment will help protect the tires. Any sign of deterioration should be evaluated before the Grayhound returns to regular road use.