1968 Austin A 40 Tires

The 1968 Austin A 40 uses two primary tire sizes: 145R13 in radial construction and 520-13 in bias-ply construction. Both sizes are associated with the A 40 Base and both are built around a 13-inch rim diameter, so the fitment question is centered more on tire type than on wheel diameter.

Choosing between them depends on how the car is set up and what kind of presentation is wanted. A 520-13 keeps the vintage numeric bias-ply format, while 145R13 uses a Euro-metric radial format. Before ordering, confirm the actual wheel width on the car and make sure any past wheel or suspension changes have not altered the fitment requirements.

The 1968 Austin A 40 uses a 13-inch rim diameter with both of its primary tire sizes. That shared wheel diameter applies whether the car is running the 145R13 radial size or the 520-13 bias-ply size, which simplifies the basic rim-diameter question for this model.

Rim diameter is only one part of the fitment picture, though. Width still matters, especially when comparing radial and bias-ply tires or considering a radial equivalent for 520-13. Checking the wheel stamping or measuring the wheel is worthwhile on an older car, particularly if it may have replacement wheels that differ from the original 13-inch setup.

520-13 is a vintage numeric bias-ply tire size. The 520 portion represents the nominal section width with the decimal omitted, meaning roughly 5.20 inches, and the 13 identifies the wheel diameter in inches. On the 1968 Austin A 40, it is the traditional bias-ply size used with a 13-inch rim.

That older sizing format matters because it points you toward a different type of tire choice than a modern radial code. Buyers usually compare 520-13 by sidewall style, brand, and whether they want to stay with bias-ply construction or evaluate one of the radial equivalents. Wheel width and clearance should be checked before treating a radial alternative as interchangeable.

520-13 is the bias-ply fitment for the 1968 Austin A 40. It uses the older numeric sizing convention and is offered in bias-ply form with appearance options that include blackwall, narrow whitewall, and wide whitewall treatments, depending on the tire selected.

That makes 520-13 the natural starting point when the goal is a traditional look and a period-style tire format. Owners considering a change should remember that the A 40 also uses a radial size, 145R13, and radial equivalents exist for 520-13 as well. Any change in construction should be checked against wheel width, tire dimensions, and available clearance on the car.

Radial equivalents for 520-13 include 155R13 as an 80-series metric radial, P155/75R13 as a P-metric 75-series radial, and P155/70R13 as a P-metric 70-series radial. A recommended rim-width range of 4-5 inches is associated with those radial-equivalent choices for this size conversion.

Those alternatives give Austin A 40 owners several ways to move from a vintage bias-ply code into radial sizing without jumping to unrelated dimensions. The three choices differ by sizing system and profile family, so they should be compared carefully against the wheel on the car. Rim width, overall tire shape, and clearance around the body and suspension all deserve attention before making the switch.

Either can be appropriate on a 1968 Austin A 40, depending on what matters most for the car. The primary bias-ply choice is 520-13, while 145R13 serves as the radial fitment, and radial equivalents are also available for the 520-13 size. The best direction depends on whether the priority is traditional appearance or a radial-style setup.

A bias-ply tire keeps the older size format and the period-style visual character many owners want on a small British car. A radial choice changes the construction and sizing convention, so it should be treated as a fitment decision rather than a simple cosmetic change. Checking wheel width, current wheel condition, and fender or suspension clearance is smart before moving from one construction type to the other.

Start with the basic role of the tire on the car. A 520-13 on a 1968 Austin A 40 is the bias-ply choice, so buyers typically compare it by construction, sidewall style, brand, tire series, and wheel compatibility rather than by modern performance categories. Available versions include blackwall, narrow whitewall, and wide whitewall designs.

The right choice depends on how the car is used and how it is meant to look. A restoration-oriented car may call for a more traditional visual treatment, while a driver-focused car may lead you toward a different construction decision altogether. It also helps to compare rim-width specifications and load figures where they are stated, especially on older wheels.

The 1968 Austin A 40 has several sidewall styles available across its tire choices. Blackwall appears in both the radial 145R13 and the bias-ply 520-13 range, while the 520-13 bias-ply selection also includes narrow whitewall and wide whitewall options. That gives the car a wider appearance range than a single blackwall-only fitment.

Sidewall style should be chosen with the car's overall presentation in mind. A blackwall usually gives the smallest and simplest visual impression, while whitewall treatments add more vintage emphasis to the profile of the car. Because sidewall style does not change the need for correct wheel fitment, keep the size and construction decision first, then refine the look with the sidewall treatment.

Michelin, Firestone, and Premium Sport all offer tires for the 1968 Austin A 40. Michelin and Firestone appear in the 145R13 radial range, while Firestone and Premium Sport cover the 520-13 bias-ply fitment. Those brand choices span several tire series and different sidewall presentations rather than one uniform product type.

Brand selection is most useful when it helps narrow the kind of tire you want, not as a ranking exercise. Some Austin A 40 owners will focus on a radial blackwall from Michelin or Firestone, while others may want a bias-ply whitewall from Firestone or Premium Sport. Compare the actual size, construction, sidewall style, and any stated rim-width or load details before deciding.

For a period-style 1968 Austin A 40, the 520-13 bias-ply size is the natural starting point because it preserves the vintage numeric sizing format used on the car. Within that size, the decision usually comes down to the visual treatment you want, such as blackwall, narrow whitewall, or wide whitewall, rather than changing to a different primary size.

That does not automatically make one brand or sidewall treatment historically exact for every car. Restoration standards vary, and details can depend on market, prior restoration choices, and the owner's target presentation. When exact originality matters, compare the tire choice with marque references, period photos, and other vehicle-specific documentation rather than relying only on general appearance.

Tire construction changes the visual character of a restored 1968 Austin A 40 almost as much as the sidewall style does. A 520-13 bias-ply keeps the older numeric size format and a more traditional presentation, while a 145R13 radial moves the car into a later metric-style radial look, even when the sidewall remains simple and understated.

That difference matters because small cars tend to show tire shape and sidewall treatment very clearly. Owners trying to preserve an earlier visual impression often stay close to the bias-ply format, while those building a more road-oriented driver may be comfortable with the radial appearance. The best result usually comes from matching tire construction to the car's intended use and restoration style.

Yes, modifications can affect tire fitment on a 1968 Austin A 40 even when the tire size itself is correct on paper. Aftermarket wheels, changes in wheel width, suspension alterations, ride-height changes, or bodywork differences can all influence how a 145R13 or 520-13 tire sits and clears the car.

That is especially important on a compact car where available space can be limited. A tire that suits the original setup may need a closer look once the wheel or suspension package has changed. Checking actual wheel diameter and width, as well as steering and fender clearance at full lock and full suspension movement, helps prevent fitment surprises.

Before driving a 1968 Austin A 40 on new tires, inspect the wheels, valve stems, and the general condition of the suspension and steering components. Make sure the new tires match the intended size and construction, seat properly on the rims, and hold stable air pressure before the car returns to regular road use.

A short visual check after installation is not enough on an older vehicle. Recheck clearance around the fenders and suspension, look for rubbing marks after the first miles, and confirm that lug hardware is secure. It is also wise to monitor pressure closely during the first drives, since collector cars can reveal wheel or sealing issues only after they have been back on the road.

520-13 tires on a collector 1968 Austin A 40 should be maintained with regular pressure checks, routine visual inspections, and careful storage habits. Bias-ply tires deserve close attention for sidewall cracking, flat-spotting after long periods of sitting, cuts, bulges, and any signs of air loss, especially on a car that is driven only occasionally.

Storage conditions make a real difference with low-use collector vehicles. Keeping the car away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the tires over time. It also pays to inspect tread and sidewalls before each outing rather than assuming low mileage means low risk, since age and storage can matter as much as wear on an older Austin.