1955 AC Tire Fitment Guide

1955 AC vehicles in this range use two tire sizes: 185R16 and 670-16, and both apply to the AC Saloon. Each size mounts on a 16-inch rim, but the construction differs, with 185R16 offered as a radial and 670-16 offered as a bias-ply. Approved rim-width information appears within the product range rather than as one single number for the whole year: 185R16 products are shown on 4.50 to 6.00 inch and 5.0 to 6.5 inch rims, while 670-16 is shown on 4.50 to 5.00 inch rims.

That means a 1955 AC buyer should identify both the intended tire size and the actual wheel width before settling on a specific tire. The rim diameter is shared, so the main distinction is not wheel diameter but construction type, profile, and the wheel-width range approved by the manufacturer of the exact product you choose.

185R16 is a metric radial size used on the 1955 AC Saloon. The 185 refers to nominal section width in millimeters, the R identifies radial construction, and the 16 is the wheel diameter in inches. Because no aspect ratio is printed in the code, this older Euro-metric style is conventionally treated as an 80-series radial rather than a lower-profile modern fitment.

For a 1955 AC owner, that size represents the radial route on the same 16-inch wheel diameter used by the bias-ply option. It is the size to investigate if you want modern radial construction while keeping the car in an era-appropriate overall diameter class, but the exact tire still needs to be matched to your wheel width and the product's tube or speed marking.

670-16 is a traditional numeric bias-ply size used on the 1955 AC Saloon. In that older sizing system, 6.70 identifies the nominal section width and 16 identifies the rim diameter in inches. It does not read like a modern metric radial code because it belongs to the earlier bias-ply sizing era and is tied to period construction rather than a modern aspect-ratio format.

A 1955 AC owner usually looks at 670-16 when authenticity, steering feel, and the visual stance of a mid-1950s bias-ply setup matter more than converting to a radial. The wheel diameter remains 16 inches, but the tire's approved rim-width range and the product's individual load or speed marking still need to be checked before final fitment.

The choice between 185R16 and 670-16 on a 1955 AC is mainly a choice between radial and bias-ply construction, since both sizes mount on 16-inch wheels and both are used on the Saloon. The 670-16 stays closer to what a mid-1950s car would have worn in period, while 185R16 brings radial construction in a size that suits the same basic wheel diameter.

Owners restoring a 1955 AC for authenticity, show presentation, or traditional steering and ride character usually lean toward 670-16. Owners who plan to spend more time on ordinary roads often prefer 185R16 because radial construction changes how the car feels in day-to-day driving. The smartest approach is to decide first what role the car serves, then match the tire to that use.

The available 1955 AC tire options in both 185R16 and 670-16 are blackwall products. That suits the restrained, European character of an AC Saloon far better than a broad whitewall treatment would in most restoration contexts. The sidewall choice is therefore straightforward here, because the variation lies in size, construction, and brand rather than in decorative sidewall treatments.

For a buyer, that simplifies the visual decision and keeps the focus on whether the car should wear a traditional bias-ply look or a radial with a more modern internal construction. If the goal is a show-oriented restoration, blackwall presentation aligns naturally with the understated British luxury and sporting image associated with AC in the mid-1950s.

Four brands appear in the available range for 1955 AC vehicles: Michelin, Avon, Vredestein, and Firestone. In 185R16 radial form, the brands are Michelin, Avon, and Vredestein. In 670-16 bias-ply form, the brands are Firestone and Avon. That gives the AC owner a mix of well-known classic-tire names across both construction types rather than a single-brand market.

Brand choice matters less than matching the correct size, construction, and wheel fitment for the car's intended use. Once that is settled, the differences to compare are the individual product's sidewall presentation, load information, tube marking, speed rating, and approved rim-width range. Looking at the brands by size first helps narrow the field quickly.

Rim-width requirements for 1955 AC tires depend on the exact size and product selected. In 185R16, one radial is approved for 4.50 to 6.00 inch rims and another is approved for 5.0 to 6.5 inch rims. In 670-16, the listed bias-ply fitment is shown on 4.50 to 5.00 inch rims. All of these tires share a 16-inch rim diameter, but they do not all carry the same width range.

That is why wheel width should be confirmed before choosing a tire, especially if the car has replacement wheels or if the original wheels have been altered over the years. A 16-inch wheel alone is not enough information. The approved width range for the specific tire you want is the figure that matters when narrowing down fitment.

Inner-tube status varies within the 1955 AC tire range rather than staying uniform across both sizes. The Michelin 185R16 is explicitly marked TT, meaning tube type, while the other 185R16 radials do not carry that same marking in their size descriptions. The 670-16 bias-ply products also do not present one universal tube statement across the size, so tube requirements should be checked at the individual tire level.

For a 1955 AC owner, the practical step is to look at the exact sidewall marking and wheel type before finalizing the setup. Older wheels, wire-wheel applications, or original rim designs often affect whether tubes are appropriate even when a tire itself may be offered in more than one configuration. Matching tire, wheel, and tube practice as a set avoids avoidable installation problems.

The two listed 1955 AC tire sizes both use a 16-inch rim diameter, so original 16-inch wheels are in the correct diameter class for either size. That does not automatically mean every original wheel width is right for every tire, because the approved width ranges differ among the available 185R16 and 670-16 products. Diameter compatibility is shared, while width compatibility still needs to be matched carefully.

This is especially important on a low-volume British car where wheel history may be less obvious than on a mass-produced domestic model. If your 1955 AC still wears its original wheels, measuring the wheel width and comparing it to the exact tire's approved range is the cleanest way to decide whether both sizes remain practical or whether one route fits the wheel more naturally.

A stored 1955 AC should be kept in a cool, dry space away from direct sunlight, electric motors, welders, furnaces, and other ozone sources that age rubber. Tire pressures should be maintained during storage, and the car should either be rolled periodically or supported in a way that reduces long-term static loading. Bias-ply tires tend to develop flat-spotting more readily during long sits, while all vintage-style tires dislike heat, moisture, and ultraviolet exposure.

That matters on a 1955 AC because both bias-ply and radial options exist, and each benefits from thoughtful storage habits. If the car rests for months at a time, inspecting the sidewalls before returning it to service is just as important as checking the battery or fuel system. Collector-car tires age from environment and time as much as from mileage.

Tires on a 1955 AC should be judged mainly by age and condition rather than mileage. A collector car can wear tread that still looks deep while the casing and rubber have aged significantly. As a general rule, tires should be evaluated closely once they are five to seven years old, and replacement becomes a serious consideration as they approach the ten-year mark, using the DOT date code and overall condition as guides.

That timeline is especially relevant for an AC that may spend long periods parked and then be expected to run at road speed with little warning. Cracking, hardening, vibration, repeated air loss, or visible casing distortion should move replacement higher on the priority list even if the odometer says the tires have seen very little use.

Tires on a 1955 AC should be inspected before every drive and again before any longer outing. Look for sidewall cracking, tread separation, embedded objects, bulges, uneven wear, and pressure loss. Because some products in the 1955 AC range may involve tube-type use, valve stems and any signs of slow leakage deserve the same attention as the tread and sidewall itself.

A brief inspection is one of the easiest ways to prevent a roadside problem on a vintage car. ACs are special-interest cars, and many spend more time parked than driven, which makes age-related issues easy to miss until the car is back on the road. A few minutes in the garage is far preferable to discovering a weakened tire after the trip has started.

A 1955 AC Saloon would have been associated with bias-ply construction in period, making 670-16 the most historically natural type among the available choices. Radial tires were emerging in Europe during the era, but a mid-1950s British saloon was still closely tied to bias-ply fitment as the mainstream original-equipment norm. No original-equipment brand should be assumed from the replacement choices alone.

For a restoration, that means size, construction, and sidewall appearance should be considered together rather than treating diameter alone as enough. If your goal is exact market- and build-specific accuracy, compare your car against factory literature, period photographs, and AC marque-club guidance. That is the best way to verify whether your specific Saloon should stay with a traditional bias-ply presentation.

Correct tire fitment matters on a shown 1955 AC because judges and knowledgeable enthusiasts often notice whether the size, construction type, and sidewall presentation suit the era. On a 1955 British saloon, a blackwall bias-ply presentation usually aligns more closely with period expectations than a modern-looking radial conversion, even when both fit the same 16-inch wheel diameter.

That does not mean every event applies the same standards. Some local and touring-oriented shows are relaxed, while marque or concours judging may scrutinize construction and appearance much more closely. If the car is being prepared for formal judging, confirm the event's expectations with AC specialists or club resources before selecting a tire simply because it is easy to drive on.

Both the Michelin X Radial and the Vredestein Sprint Classic are offered in 185R16 for the 1955 AC, and both are blackwall radials on 16-inch rims. The Michelin is marked 92S TT, carries a 4.50 to 6.00 inch rim-width range, and is tube type. The Vredestein is marked 93V, lists a 1,433-lb maximum load at 51 psi, and fits 5.0 to 6.5 inch rims. Each weighs 26 pounds in the listed version.

For the buyer, the main differences are speed rating, tube marking, and approved wheel-width range rather than a dramatic difference in visual style. If your wheel is on the narrower side, the Michelin's published range may be the more natural starting point. If your wheel is wider and you want the higher listed speed rating, the Vredestein becomes a more relevant comparison.

1955 AC tires can be suitable for highway use when the tire's condition, size, and speed rating align with the way the car is driven. In the available range, the 185R16 Michelin carries an S rating to 112 mph, while the 185R16 Avon and Vredestein carry V ratings to 149 mph. The Avon 670H16 bias-ply is H-rated to 130 mph. Those ratings are well above normal U.S. highway speeds, but the condition of the tire and the condition of the car itself matter just as much.

A 1955 AC is still a mid-century car with vintage chassis, braking, and suspension expectations, so mechanical readiness remains the real governor of comfortable road use. A fresh, correctly fitted tire is only one part of the picture. If the car has been stored, inspect every tire closely and treat age, inflation, and wheel condition as seriously as the speed symbol on the sidewall.

Inflation pressure on a 1955 AC should follow the vehicle's original recommendations first, then be checked against the reproduction tire maker's published maximum figures for the exact tire chosen. Within the available range, Firestone's 670-16 lists 1,130 lbs at 30 psi, and Vredestein's 185R16 lists 1,433 lbs at 51 psi. Those are maximum load-and-pressure references for those specific tires, not a universal operating pressure to transfer across the whole 1955 AC range.

The practical approach is to identify the exact size and product on the car, then compare the tire's published information with period AC guidance for normal running pressure. Using a figure from one size or one brand on another tire can lead to poor ride, irregular wear, or handling that does not suit the construction. Pressure should always match the exact tire and application.

Before a longer trip in a 1955 AC, inspect every tire for cracking, cuts, bulges, uneven wear, and proper inflation, and do not forget the spare. Check valve stems carefully, especially if the setup uses tube-type fitment, and make sure each wheel is secure and free from visible damage. On a collector car, the tire inspection should happen alongside checks of brakes, steering, fluids, cooling, and lighting rather than as a stand-alone task.

That broader pre-drive routine matters because vintage cars often sit longer than modern cars, and problems can appear between outings even when the last drive was uneventful. A 1955 AC prepared for a longer run should feel settled and predictable before it leaves the driveway. If any tire shows age-related distress or repeated air loss, solve that first and postpone the trip.