1957 AC Tire Fitment Guide

1957 AC vehicles use three distinct tire sizes across two models. The AC Ace uses 550-16 bias-ply tires, while the AC Saloon uses either 185R16 radial tires or 670-16 bias-ply tires. All three sizes fit 16-inch rims, but the approved rim-width range changes by size where that guidance is available: 550-16 appears on 3.25- to 4.00-inch rims, 185R16 appears on 4.50- to 6.50-inch rims depending on the tire, and 670-16 appears on 4.50- to 5.00-inch rims where specified.

That means year and make alone are not enough for 1957 AC fitment. Ace owners can focus on 550-16 choices, while Saloon owners need to decide whether they are staying with a bias-ply format or moving to a radial option in 185R16. Before selecting a tire, compare the actual wheel on the car to the tire maker's approved rim-width range, especially if the wheels have been changed during restoration or past service.

On a 1957 AC, 550-16 is a traditional numeric bias-ply size. The 5.50 figure is the nominal section width in inches, written without a decimal point, and the 16 identifies the wheel diameter in inches. In the 1957 AC range, that size applies to the Ace and is offered as a bias-ply tire in several brand and sidewall combinations, including blackwall and wide whitewall versions.

For an Ace owner, the meaning of the code matters because it points to a pre-metric, crossply-era fitment rather than a later radial designation. That usually appeals to restorers who want the visual stance and steering character associated with period tire construction. The next step is not to convert it into a modern metric size by guesswork, but to choose among the available 550-16 products based on sidewall appearance and wheel-width compatibility.

On a 1957 AC, 185R16 is a Euro-metric radial size. The 185 is the tire's section width in millimeters, the R indicates radial construction, and the 16 is the wheel diameter in inches. Within the 1957 AC line, that size belongs to the Saloon and appears in blackwall radial offerings from Michelin, Avon, and Vredestein, with speed ratings ranging from S to V depending on the specific tire.

That code tells a buyer the tire is from a later sizing language than the older numeric bias-ply system. For a Saloon owner, choosing 185R16 generally means pursuing a radial-style road feel while staying on a 16-inch wheel. It also means checking the exact sidewall marking on the product, because one version is marked tube type and others carry higher speed-rated V-spec markings that can matter if originality and road use are both part of the plan.

For a 1957 AC Saloon, the choice between 185R16 and 670-16 is mainly a choice between radial and bias-ply construction, since both use 16-inch wheels. The 185R16 options are radial blackwalls from Michelin, Avon, and Vredestein, while the 670-16 options are bias-ply blackwalls from Firestone and Avon. The radial size also carries explicit speed ratings from S to V depending on brand, while the Avon 670H16 example carries an H rating.

A Saloon restored with originality in mind will usually lean toward the 670-16 bias-ply route, especially if the goal is an era-appropriate appearance and crossply driving feel. A car intended for more regular road use may point you toward 185R16 radials instead. The most useful way to decide is to start with how the car will be driven, then verify wheel width and the exact sidewall marking on the tire you are considering.

1957 AC tire sidewall styles vary by size. The 550-16 size used on the AC Ace is available in both blackwall and wide whitewall form, while the 185R16 and 670-16 sizes used on the AC Saloon are offered here as blackwalls. That gives Ace owners a broader visual range, while Saloon owners in these sizes are looking at a more restrained sidewall presentation.

From a period-authenticity standpoint, blackwall tires are the most conservative choice for a British sporting or touring car of this era. Wide whitewalls create a more stylized look and may suit a custom presentation better than a strict factory-style restoration, particularly on the Ace's 550-16 size where they are available. If show judging matters, check the expectations of the event or marque community before choosing a whitewall simply because it is offered.

Several brands cover 1957 AC fitments, but they are split by size. The 550-16 Ace size is available from Excelsior, Avon, BFGoodrich, and Firestone. The 185R16 Saloon radial size is available from Michelin, Avon, and Vredestein. The 670-16 Saloon bias-ply size is available from Firestone and Avon.

That spread gives buyers a mix of traditional American and European names, which can matter if the car's restoration theme is as important as the fitment itself. An Ace owner shopping 550-16 has the widest variety of brand and sidewall presentation, while a Saloon owner is choosing among fewer products but across two distinct constructions. It is worth narrowing the decision by model and size first, because the brand list changes significantly once you do.

1957 AC rim-width guidance depends on the size. The 550-16 tires used on the Ace are listed for 3.25- to 4.00-inch rims on products where that specification appears. The 185R16 Saloon radial size is listed on 4.50- to 6.00-inch rims for one product and 5.0- to 6.5-inch rims for another. The 670-16 Saloon bias-ply size appears on 4.50- to 5.00-inch rims where that range is stated.

Those ranges are one of the most important setup checks before ordering, especially on a car that may have seen wheel changes over the years. A 16-inch diameter match alone is not enough if the wheel is outside the approved width range for the tire you want. Measure the actual wheel, compare it to the chosen product's fitment range, and avoid assuming that one 16-inch 1957 AC tire can substitute for another without that check.

Inner-tube requirements on 1957 AC tires depend on the exact size and product. One 185R16 Michelin radial is explicitly marked TT, meaning tube type, while the other 185R16 radials shown do not carry the same marking in the size description. The 550-16 and 670-16 bias-ply products are not consistently marked one way or the other in the size field, so tube status can vary by product and wheel type rather than by size alone.

For that reason, tube use should be confirmed at the product level and also matched to the wheel itself. Older original-style wheels, wire wheels, and certain restoration-era rim constructions may call for a tube even when a buyer expects otherwise. The safest approach is to treat tube fitment as part of the complete wheel-and-tire package, not as a blanket rule for every 1957 AC tire with the same nominal size.

All of the listed 1957 AC tire sizes are built for 16-inch wheels, so the wheel diameter itself is consistent across the Ace and Saloon sizes. That said, the approved rim-width ranges differ meaningfully between 550-16, 185R16, and 670-16. A wheel that works with one of those sizes may not be the correct width for another, even though the bead seat diameter is still 16 inches.

In practical terms, original wheels can often remain part of the equation, but only if their actual width matches the tire being considered. This is especially relevant for Saloon owners choosing between 670-16 bias-ply and 185R16 radial products, since those tires do not share the same width recommendations. Verify the wheel first, then choose the tire, rather than assuming every 16-inch AC wheel can safely accept every listed 1957 AC size.

A stored 1957 AC should be kept out of direct sunlight, away from electric motors or other ozone-producing equipment, and protected from standing moisture and large temperature swings. Tire pressure should be maintained during storage, and the car should be moved periodically or supported appropriately if it will sit for a long period. Bias-ply tires such as 550-16 and 670-16 are more prone to taking temporary flat spots during long static periods than radial 185R16 tires.

That matters because collector cars often spend far more time parked than driven. If your AC is stored through a season, inspect sidewalls and tread before returning it to use, and give bias-ply tires a few miles to round out before judging ride feel. Good storage habits do as much for preserving the tire's appearance and structure as they do for preventing surprises the next time the car comes out.

On a low-use collector car like a 1957 AC, tire age usually matters more than tread wear. A practical rule is to begin evaluating them closely once they are around five to seven years old and to treat the ten-year point as a serious replacement consideration, even if the tread still looks usable. The DOT date code on the tire provides the manufacturing date and is a better guide than mileage on a car that may only be driven occasionally.

That guideline applies whether your AC is fitted with 550-16 or 670-16 bias-ply tires or 185R16 radials. Visible cracking, persistent air loss, hardening of the rubber, or changes in ride feel can all move replacement higher on the priority list before the calendar reaches a round number. On collector cars, tires often age out before they wear out, so calendar-based attention is the right habit.

Tires on a 1957 AC should be checked before every drive, and more thoroughly before any longer outing. Look for sidewall cracking, tread separation, embedded debris, cuts, bulges, irregular wear, and any sign that the tire is no longer holding pressure properly. If the setup uses tube-type components, include the valve stems and any evidence of slow leakage in the inspection routine.

Short local drives can hide tire issues that become much more serious once heat builds on the road. A pre-drive walkaround takes only a few minutes and is especially important on cars that may sit for weeks at a time between uses. For a 1957 AC, that quick check should become part of the same routine as checking fluid levels and basic chassis condition before heading out.

A 1957 AC Ace would have been associated with a bias-ply tire construction in period, and the listed fitment here is 550-16. That aligns with the era, when crossply tires were still the established choice on many British sports cars. No original-equipment brand should be assumed from that alone, since factory supply could vary by market and production run even when the basic size and construction type remained consistent.

For restoration work, the most faithful starting point is to stay with the 550-16 bias-ply format and then narrow the choice by sidewall appearance and wheel compatibility. If the goal is top-tier authenticity, confirm details such as sidewall treatment with AC marque specialists, period road tests, and club resources. That extra step matters more than simply picking any tire that happens to share the same nominal size.

Correct tire fitment matters on a 1957 AC because show judging often considers size, construction, and sidewall appearance as part of overall authenticity. On a car judged for originality, a modern radial can be viewed differently from a period-style bias-ply, and a wide whitewall can change the visual character of the car just as much as an incorrect wheel finish would. The standard can vary by event, but tire presentation is rarely ignored on serious restored cars.

That makes it important to decide early whether the car is being built for concours, touring, or a blend of both. An Ace aimed at factory-style presentation will usually be approached differently from a Saloon built for regular road use, especially when the Saloon has both radial and bias-ply paths available. Before finalizing a set, compare the tire's size, construction, and sidewall style against the expectations of the club or show where the car will appear.

For the 1957 AC Saloon in 185R16, Michelin X Radial and Vredestein Sprint Classic share the same nominal size but differ in sidewall marking details and fitment specs. The Michelin is marked 185R16 92S TT, making it an S-rated tube-type radial with a 4.50- to 6.00-inch rim-width range where listed. The Vredestein is marked 185VR16 93V, carries a V speed rating, lists a 5.0- to 6.5-inch rim-width range, and includes a higher published load figure at 51 psi.

Those differences affect selection more than the matching 16-inch diameter does. A buyer comparing them should look at wheel width first, then decide whether the tire's sidewall marking and speed rating better suit the intended style of use. Neither should be treated as interchangeable by default simply because both are 185R16-family radials; the exact rim and the desired character of the finished Saloon still need to guide the choice.

1957 AC tires can be suitable for highway use when the correct size, age, condition, and inflation are all in order. The radial 185R16 options include S-rated tires to 112 mph and V-rated tires to 149 mph, while the Avon 670H16 bias-ply example carries an H rating to 130 mph. Highway safety, though, is not determined by speed rating alone on a 1957 automobile, because braking, suspension condition, alignment, and the car's general mechanical health matter just as much.

For most normal highway travel, the limiting factor on a 1957 AC is likely to be the overall vehicle and the tire's age or condition rather than the published ceiling on the sidewall. A well-kept radial Saloon may feel different on the road than a bias-ply Ace or bias-ply Saloon, but any of them should be approached with the expectations appropriate to a mid-century car. Inspect the tires carefully and drive within the car's vintage capabilities.

Inflation pressure on a 1957 AC should be matched to the specific tire and then cross-checked against the vehicle's factory guidance. Published load-and-pressure examples here include 550-16 Firestone at 840 lbs at 32 psi, 670-16 Firestone at 1130 lbs at 30 psi, and 185VR16 Vredestein at 1,433 lbs at 51 psi. Those figures are tire ratings, not blanket instructions for every 1957 AC size or every product within the same size family.

The right way to set pressure is to start with the original owner's manual or marque guidance for the car, then confirm that the chosen reproduction or modern tire's specifications are being respected. Do not carry a pressure number from one size to another or from a bias-ply product to a radial just because the rim diameter matches. Inflation is one area where exact tire identity matters every bit as much as the vehicle itself.

Before a longer drive in a 1957 AC, inspect each tire for cracking, cuts, bulges, irregular wear, and any sign of tread or sidewall damage. Confirm inflation when the tires are cold, inspect valve stems, and make sure the spare is usable as well. If the car is fitted with a tube-type setup, include tube-related leakage concerns in the check, and pay close attention to any tire that has been sitting under load for an extended period.

That tire inspection should be part of a broader vintage-car pre-drive routine that also covers fluids, brakes, steering, and basic fastener security. A collector car can feel perfectly fine on a short outing and still reveal age-related issues once heat and distance build. Taking a few extra minutes before departure is especially worthwhile on a 1957 AC, where the car's age makes prevention much more valuable than roadside improvisation.