In 1963, AC stood at a fascinating crossroads, building cars that ranged from the refined Ace roadster to the hard-edged Cobra, while the Grayhound carried the marque’s sporting character in a more practical direction. That variety makes tire selection for 1963 AC especially important, because the model range does not share one universal size. Three bias-ply sizes appear across the year, with the Ace using a 16-inch fitment and the Cobra and Grayhound centered on two different 15-inch options. The first step is to identify your exact model, then confirm whether you are matching an original-style restoration look or choosing the size that best suits your wheel and intended use.
Which Tire Size Is Right for Your 1963 AC
Three tire sizes are used across 1963 AC vehicles, and they vary by model rather than carrying across the full range. The key decision is to confirm your exact model and wheel diameter first, since the Ace uses a 16-inch size while Cobra and Grayhound applications use 15-inch sizes. Understanding that distinction before choosing a product saves time and helps ensure the right match.
Year(s): 1963|Fit(s): e|Construction: Bias Ply|Rim: 16 in
550-16 is a numeric bias-ply size in which the first number represents nominal section width and the 16 indicates a 16-inch wheel. This Ace-specific size is available from Excelsior, Avon, BFGoodrich, and Firestone in blackwall and wide whitewall styles, with load figures reaching 992 lbs on some products. It suits an owner who wants the narrow, period-correct bias-ply look associated with early 1960s British sports-car fitment. Rim-width coverage in this size spans 3.25 to 4.00 inches where specified.
Year(s): 1963|Fit(s): Cobra, Grayhound|Construction: Bias Ply|Rim: 15 in
640-15 is a numeric bias-ply size with a nominal section-width code up front and a 15-inch rim diameter after the dash. This size is specific to the 1963 AC Cobra and 1963 AC Grayhound rather than the full AC range, and it is offered by BFGoodrich and Firestone with wide whitewall and narrow whitewall treatments. It is the choice for owners of those models who want a bias-ply tire on a 15-inch wheel without stepping up to the larger 670-15 fitment. Rim-width recommendations where stated run from 4.00 to 5.00 inches, depending on the tire.
Year(s): 1963|Fit(s): Cobra, Grayhound|Construction: Bias Ply|Rim: 15 in
670-15 is a numeric bias-ply size that uses a nominal section-width code and fits a 15-inch wheel. This size is also specific to the 1963 AC Cobra and 1963 AC Grayhound, and it is available from Firestone, US Royal, Coker Classic, and Universal Vintage Tire in blackwall and wide whitewall styles, with load ratings reaching 1550 lbs at 32 psi on some versions. It is the larger of the two 15-inch AC sizes and will appeal to owners aiming for a fuller period stance while staying with bias-ply construction. Rim-width ranges where stated run from 4.50 to 6.00 inches.
The two 15-inch sizes can often share the same wheel diameter, but rim-width suitability should be confirmed against the specific tire before making a final choice.
1963 AC Models
Three 1963 AC models are covered here. Tire size varies by model, so year and make alone are not enough; the Ace uses a different wheel diameter from the Cobra and Grayhound, and the Cobra/Grayhound pair can also split between two 15-inch sizes. Select your model below to narrow the fitment history and tire choices more precisely.
1963 AC e
The 1963 ACe was the elegant, lightweight sports car that helped establish AC’s reputation well before the Cobra became the headline act. Its tire fitment mounts on 16-inch wheels, giving Ace owners a distinctly different starting point from other AC models of the same year. For restoration-minded buyers, that model-specific wheel diameter is the first thing to verify before comparing sidewall style.
The 1963 AC Cobra combined AC’s compact British roadster chassis with American V8 power, creating one of the defining sports cars of the era. Its tires mount on 15-inch wheels, and both AC Cobra sizes for this year stay within traditional bias-ply construction. That means the main fitment question is which of the two 15-inch sizes matches your car’s wheel and stance expectations.
The 1963 AC Grayhound carried AC’s sporting engineering into a longer-wheelbase, more practical layout, making it distinct from the company’s open sports cars while still feeling very much part of the same family. Grayhound applications use 15-inch wheel fitments, sharing the same basic tire-size family as the Cobra rather than the Ace. Buyers should confirm which 15-inch size suits their specific car before focusing on whitewall or blackwall appearance.
Eighteen products are available across three tire sizes for 1963 AC vehicles. The 550-16 comes from Excelsior, Avon, BFGoodrich, and Firestone in bias-ply construction with blackwall and wide whitewall styles; 640-15 comes from BFGoodrich and Firestone in bias-ply form with narrow and wide whitewalls; 670-15 comes from Firestone, US Royal, Coker Classic, and Universal Vintage Tire in bias-ply form with blackwall and wide whitewall options.
These answers focus on how 1963 AC tire sizing changes between the Ace, Cobra, and Grayhound, how the three bias-ply sizes relate to their 15-inch and 16-inch wheels, and what to check for restoration accuracy, setup, and long-term collector use.
Size Basics & Fitment
What tire sizes fit 1963 AC vehicles?
1963 AC vehicles use three tire sizes, and they are not shared across the entire model range. The AC Ace uses 550-16 on a 16-inch rim, while the AC Cobra and AC Grayhound use 640-15 or 670-15 on 15-inch rims. Rim-width ranges where specified are 3.25 to 4.00 inches for 550-16, 4.00 to 5.00 inches for 640-15, and 4.50 to 6.00 inches for 670-15.
That means the first fitment step for any 1963 AC is identifying the model, then confirming whether the car is on 15-inch or 16-inch wheels. After that, compare the actual wheel width to the tire you are considering, because the two 15-inch sizes do not cover exactly the same rim-width range. If the car has been restored, modified, or re-wheeled over the years, a quick wheel measurement before ordering can prevent an expensive mismatch.
What does 550-16 mean on a 1963 AC tire?
On a 1963 AC, 550-16 is a numeric bias-ply size. The 550 portion is the older nominal section-width code, and the 16 identifies the wheel diameter in inches. On 1963 AC applications, that size belongs to the Ace and is offered in both blackwall and wide whitewall forms.
For an Ace owner, 550-16 points you toward a narrow, traditional cross-section and a true 16-inch fitment, which immediately separates it from Cobra and Grayhound tires. That is useful because many classic-car buyers start with year and make, but AC used different wheel diameters across the lineup. Once 550-16 is confirmed on the car, the next choice becomes visual style and brand preference rather than whether it fits a 15-inch wheel.
Do all 1963 AC models use the same tire size?
No. 1963 AC models split into two fitment groups, with the Ace using 550-16 and the Cobra and Grayhound using 640-15 or 670-15. All three sizes are bias-ply, but the wheel diameter changes from 16 inches on the Ace to 15 inches on the Cobra and Grayhound.
That distinction matters because it changes the fitment search immediately. If you own a Cobra or Grayhound, the question is which 15-inch size suits your car and wheel; if you own an Ace, the 16-inch tire family is its own path. Buyers sorting through an old registration, project car, or partially restored AC should confirm the body style before choosing a tire, since model identification is more important here than make alone.
Buying the Right Tire
What sidewall styles are available for 1963 AC tires?
1963 AC tires are available in several sidewall styles depending on size. The 550-16 used on the Ace comes in blackwall and wide whitewall versions. The 640-15 used on Cobra and Grayhound appears in narrow whitewall and wide whitewall form, while 670-15 is offered in blackwall and wide whitewall styles.
Sidewall choice affects the final look of the car as much as the size itself. A blackwall usually gives a more understated sporting appearance, while whitewalls can push the car toward a more formal or show-oriented presentation depending on the build. For a 1963 AC being judged for authenticity, sidewall style should be checked against period photos, marque references, and the market the car was delivered to, since buyer taste and original presentation could vary.
What brands make tires for 1963 AC vehicles?
Several brands cover 1963 AC applications. The 550-16 is available from Excelsior, Avon, BFGoodrich, and Firestone. The 640-15 is available from BFGoodrich and Firestone, and the 670-15 is available from Firestone, US Royal, Coker Classic, and Universal Vintage Tire.
That brand spread gives owners room to choose by appearance and preferred period character within the correct size family. An Ace owner may focus on keeping a British sports-car feel, while Cobra and Grayhound owners often compare whitewall width and overall visual stance within the 15-inch offerings. The most useful approach is to settle the correct size first, then compare the brands available in that exact size rather than assuming every AC model shares the same choices.
What is the difference between 640-15 and 670-15 for a 1963 AC?
On a 1963 AC Cobra or 1963 AC Grayhound, both 640-15 and 670-15 are bias-ply 15-inch sizes, but they are not identical. The 640-15 covers rim widths from 4.00 to 5.00 inches where specified and appears mainly in whitewall variations, while 670-15 extends from 4.50 to 6.00 inches where specified and is available in blackwall and wide whitewall versions. Load ratings also run higher on some 670-15 products, reaching 1550 lbs at 32 psi.
In practical terms, that makes 640-15 and 670-15 a matter of matching the wheel and the look of the car rather than simply picking any 15-inch tire. A narrower wheel may point you toward 640-15, while a wider wheel or a fuller side profile may favor 670-15. Because both sizes appear on the same AC models, checking the actual wheel width is the cleanest way to narrow the choice.
Fitting & Setup
What rim width do 1963 AC tires require?
Rim-width guidance for 1963 AC tires depends on the size. The 550-16 used on the AC Ace fits 3.25 to 4.00-inch rims where specified. The 640-15 used on AC Cobra and AC Grayhound tires fits 4.00 to 5.00-inch rims depending on the product, and the 670-15 fits 4.50 to 6.00-inch rims where that information is supplied.
Those ranges matter because two tires with the same wheel diameter can still prefer different wheel widths. That is especially important on Cobra and Grayhound applications, where both available sizes are 15-inch tires but do not overlap perfectly in wheel-width recommendations. Measuring the wheel before choosing a tire is more reliable than guessing from appearance, especially on older cars that may have changed wheels during restoration or long-term ownership.
Do 1963 AC tires require inner tubes?
The 1963 AC tires covered here are all bias-ply products, but the size markings shown do not consistently identify tube-type or tubeless construction across every product. That means tube use should be confirmed by the exact tire’s sidewall marking and by the wheel design on the car, rather than assumed from size alone.
This matters most on a restored or long-owned AC, because the tire and wheel may no longer match the car’s original setup. A wheel intended for tube-type service should stay in that lane, while a tire marked for tubeless use still has to be appropriate for the rim it is mounted on. If there is any doubt, confirm the tire’s marking and inspect the wheel condition, valve-hole setup, and sealing surface before final assembly.
Can the original 1963 AC wheels be used with all tire sizes?
Original 1963 AC wheels cannot be treated as universal across all three sizes, because the Ace uses a 16-inch tire and the Cobra and Grayhound use 15-inch tires. Within the Cobra and Grayhound family, both 640-15 and 670-15 share the same 15-inch rim diameter, but their recommended rim-width ranges are different.
That means an original Ace wheel is in a different fitment category from original Cobra or Grayhound wheels. For the 15-inch AC models, wheel diameter compatibility alone does not settle the question; the wheel also needs to fall within the appropriate width range for the tire being considered. If you are working with factory wheels, widened wheels, or reproduction wheels, verify both dimensions before mounting the tire.
Maintenance, Storage & Longevity
How should I store a 1963 AC when the tires are fitted?
A 1963 AC should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, welders, and other ozone-producing equipment. Bias-ply tires can develop flat spotting more readily during long static storage, so maintaining proper inflation and moving the car periodically is helpful. Clean, dry floors and protection from standing moisture also help preserve the casing and sidewalls.
If the car will sit for an extended period, many collectors either roll it occasionally or support it in a way that reduces constant load on one patch of the tire. The goal is to avoid prolonged stress in one position without creating new problems from improper support. A quick visual check after storage and before the next drive is wise, because collector cars often age the tires more from time and environment than from mileage.
How long do tires on a 1963 AC typically last?
On a 1963 AC, tire life should be judged more by age and condition than by tread wear alone. A common collector-car guideline is to begin paying close attention once a tire is around five to seven years old and to treat around ten years as a serious replacement consideration regardless of mileage. The DOT date code, if present on the tire, is the starting point for that age check.
That approach matters because many ACs are driven lightly, which can leave a tire looking usable long after the rubber has begun to harden or crack. Storage conditions, inflation habits, and exposure to sunlight or ozone can shorten usable life even when the tread still appears deep. If the age is borderline, combine the date check with a careful inspection of the sidewalls, tread base, and overall ride quality before planning regular road use.
How often should tires on a 1963 AC be inspected?
Tires on a 1963 AC should be inspected before every drive, and they deserve a more thorough check before any extended outing. Look for sidewall cracking, cuts, bulges, irregular wear, signs of impact damage, and any loss of pressure since the last drive. Valve stems and the spare tire should be part of the same routine.
Frequent inspection is especially important on low-mile collector cars because age-related issues can appear before the tread looks worn. An AC that feels fine on short local trips can still reveal pressure loss, casing stress, or sidewall deterioration once it is driven longer and warmed up. Building a quick tire check into your pre-drive habit is one of the easiest ways to catch trouble early without turning every drive into a full workshop session.
Restoration & Authenticity
What tires were originally fitted to the 1963 AC Ace?
A 1963 AC Ace would have been associated with bias-ply construction in period, and the size used here is 550-16. That aligns with the era and the Ace’s character as a lightweight British sports car from the early 1960s, when bias-ply tires were still the expected fitment in many applications. A specific original equipment brand should be confirmed through period literature or marque research rather than assumed.
For a restoration, the practical takeaway is that construction type, size, and sidewall appearance matter more than simply finding any tire that fits the wheel. If the goal is show-level accuracy, compare the tire to factory photos, road-test images, and club references for your market. AC specialists and marque clubs are especially helpful with cars that may have export-market differences or long ownership histories.
Does correct tire fitment matter for showing a 1963 AC?
Yes, correct tire fitment matters when a 1963 AC is judged for authenticity. Size, construction type, and sidewall style all influence whether the car looks right for its era, and an incorrect wheel diameter or visibly wrong sidewall treatment can stand out quickly on a carefully restored car. For 1963 AC applications, even choosing between 15-inch and 16-inch fitment begins with the correct model identification.
That is why restorers often treat tires as part of the car’s finished presentation rather than a last-minute consumable. An Ace with the wrong wheel diameter or a Cobra/Grayhound on an unsuitable sidewall style can lose the visual balance the car should have. Event rules vary, so anyone preparing for judged display should compare against period references and consult the relevant AC club or judging standard before making a final selection.
What is the difference between Firestone and BFGoodrich 640-15 tires for the 1963 AC?
For the 1963 AC in 640-15, BFGoodrich and Firestone share the same basic bias-ply construction and both offer wide whitewall options, but they differ in details. BFGoodrich appears with a 3.00-inch whitewall and a 4.00 to 4.50-inch rim-width range, while Firestone appears with 2.75-inch, 2.125-inch, and 1.00-inch whitewall versions and a 4.50 to 5.00-inch rim-width range. Some Firestone 640-15 versions also carry a lower 970-lb load figure, while others match the 1190-lb figure found on BFGoodrich and Firestone wide whitewalls.
That makes the choice about more than brand name alone. Wheel width, whitewall width, and the visual character you want all come into play, especially on a car whose final stance and detailing matter. On a period-sensitive restoration, whitewall width can noticeably change the car’s presence, so it is worth comparing the exact tire rather than assuming all 640-15 offerings are interchangeable in appearance.
Safety & Road Use
Are 1963 AC tires safe for highway driving?
1963 AC tires in the sizes covered here are bias-ply products, and one 550-16 version carries an 80L marking, which corresponds to a 75 mph speed ceiling. Other products do not consistently show a speed letter in the available size markings, so highway use should be approached with the broader realities of a 1963 AC in mind. On cars of this era, tire condition, wheel condition, suspension health, braking performance, and alignment are often just as important as the tire itself.
For normal collector-car road use, a fresh, properly fitted bias-ply tire in good condition can be entirely reasonable when matched to the way the car is actually driven. The main point is to treat the whole vehicle as a period machine rather than expecting modern-car tolerance for sustained speed, neglected maintenance, or poor setup. Before regular highway use, confirm age, pressure, visible condition, and overall mechanical readiness instead of relying on appearance alone.
What inflation pressure should I use for 1963 AC tires?
Inflation pressure for a 1963 AC should start with the vehicle manufacturer’s recommendation for the model and size, then be cross-checked against the tire maker’s rated load-and-pressure information. Among these sizes, some products show 550-16 at 840 lbs at 32 psi or 992 lbs, 640-15 at 970 or 1190 lbs at 32 psi, and 670-15 at 1450 or 1550 lbs at 32 psi. Those figures describe load capacity at a stated pressure and should not be transferred from one size to another.
The practical takeaway is to avoid guessing by appearance or by using one pressure for every AC model. Ace, Cobra, and Grayhound fitments differ, and even within a size the tire you choose may not carry identical markings. Use the owner’s manual or marque reference for the car’s target pressure baseline, then confirm that the chosen reproduction tire’s sidewall information supports the intended use and load.
What should I check before taking a 1963 AC on a longer drive?
Before a longer drive in a 1963 AC, inspect each tire for sidewall cracking, tread separation, cuts, bulges, uneven wear, and correct cold inflation pressure. Check the valve stems, confirm that the spare is usable, and make sure the wheel hardware and overall wheel condition are sound. Because AC used different tire sizes across the Ace, Cobra, and Grayhound, it is also smart to verify that the tire size on the car matches the wheel actually fitted to it.
That tire inspection should be part of a broader pre-drive routine for any early 1960s performance or touring car. Brake feel, steering play, suspension condition, fluid levels, and cooling-system behavior can matter just as much once the trip gets longer. A few careful minutes in the garage is usually enough to spot aging tires or setup issues before they turn a good drive into an avoidable roadside problem.
