1974 MG Tire Fitment Guide

1974 MG vehicles use four tire sizes across two models. The MGB uses 165R14, 155R14, and 520-14, all of which mount on 14-inch wheels. The Midget uses 145R13, which mounts on a 13-inch wheel. Where approved rim-width guidance is present, 165R14 spans 4.0 to 6.0 inches depending on product, 155R14 runs 4.00 to 5.50 inches, 520-14 runs 3.50 to 4.00 inches, and 145R13 runs 4.00 to 5.00 inches.

That means year and make alone are not enough for a correct choice on a 1974 MG. Start by confirming whether the car is an MGB or a Midget, then confirm the wheel diameter on the car, especially if it has been restored or modified over time. MGB owners also need to decide whether they want a radial tire for classic road driving or a bias-ply tire for a more period-style presentation.

On a 1974 MG, 520-14 is a numeric bias-ply size. The 5.20 portion refers to the nominal section width in inches, and the 14 identifies the wheel diameter in inches. Unlike a modern metric radial code, it does not use a millimeter width and aspect-ratio format, and the construction is bias-ply rather than radial.

That size matters mainly to 1974 MG MGB owners who want the older-style tire construction and appearance associated with earlier sports car practice. It should not be treated as interchangeable with the Midget's 145R13 because the wheel diameter is different, and it should not be chosen just because the car is from the same year and make. Confirm the actual wheel on the car and the type of restoration or road use you have in mind before selecting it.

No. The 1974 MG MGB uses 14-inch tire sizes, while the 1974 MG Midget uses a 13-inch tire size. Even within the MGB, there is more than one fitment direction, with two radial sizes and one numeric bias-ply size. The model name changes the correct tire choice in a very direct way.

That makes identification especially important if the car has changed hands, wears replacement wheels, or is partway through a restoration. An MGB owner can compare 165R14, 155R14, and 520-14, but a Midget owner should be looking at 145R13 instead. Once you have the model confirmed, the next step is to compare the construction style and wheel diameter rather than assuming all 1974 MG sports cars shared the same tire.

For a 1974 MG MGB, that choice is really between bias-ply and radial construction rather than between two unrelated vehicles. The 520-14 is the bias-ply option, while 155R14 and 165R14 are radial options on the same 14-inch wheel diameter. Bias-ply tires preserve a more vintage construction style and visual impression, while radial tires reflect the later driving character many owners want in a road-driven MGB.

If your goal is a period-style restoration look, the 520-14 is the natural direction to investigate. If the car will spend more time on real roads and you prefer the habits of a classic radial, start with 155R14 or 165R14 and compare the tire you have now against the wheel width on the car. The decision should follow the kind of MG experience you want, not just the fact that all three sizes fit the MGB category.

1974 MG radial sizes here are blackwall tires. That includes 165R14 and 155R14 for the MGB and 145R13 for the Midget. The MGB's 520-14 bias-ply option is available with narrow whitewall styling. Those sidewall choices create a clear visual split between the radial and bias-ply offerings for this year and make.

For many British sports car restorations, blackwall radials look most familiar for road-driven 1970s MGs, while a narrow whitewall bias-ply tire creates a more stylized vintage presentation. Whether that look is correct for a particular show standard depends on the market, event, and restoration philosophy. If authenticity matters, compare the tire on the car to period photos and ask an MG marque specialist what your intended judging class expects.

1974 MG tires come from several brands depending on size. The 165R14 is available from Pirelli, Michelin, and Vredestein. The 155R14 comes from Michelin and Firestone, the 145R13 comes from Michelin and Firestone, and the 520-14 bias-ply size comes from Premium Sport. Brand choice is tied to size first, then to the construction style and appearance you want.

That means you should not start with brand alone and work backward. An MGB owner who wants a radial has different brand paths than an MGB owner who wants a bias-ply whitewall, and a Midget owner is in a different wheel diameter entirely. Once you know the correct size, compare brand by sidewall look, speed rating where marked, and approved rim-width range if your car's wheels are not stock.

Rim-width guidance varies by size and sometimes by product. For 165R14, approved widths run from 4.0 to 6.0 inches depending on the tire, with examples at 4.0 to 5.5 and 4.50 to 6.00. The 155R14 runs 4.00 to 5.50 inches where stated, 520-14 runs 3.50 to 4.00 inches, and 145R13 runs 4.00 to 5.00 inches.

That range is especially important on a 1974 MG because many cars have had wheels changed during decades of ownership. A tire can share the correct wheel diameter and still be a poor match for the wheel width if the wheel is too narrow or too wide for the product you choose. Measure the actual wheel on the car or confirm its specification before finalizing the tire, particularly with MGB fitments where several 14-inch choices exist.

Tube status varies by product on 1974 MG tires. Some radial products carry a TL tubeless marking, including examples in 165R14, 155R14, and 145R13, while other products in those same sizes do not show the same marking. The 520-14 bias-ply products do not carry a consistent tube notation here either, so the exact requirement should be confirmed on the specific tire you choose and against the wheel type being used.

That matters because a tubeless-capable tire and a wheel designed to seal tubeless are not automatically the same thing on an older MG. Original wheel condition, rivets, corrosion, and the wheel's design all affect the final setup. Before mounting, verify the sidewall marking on the exact tire and make sure the installer understands whether your wheel should be run with a tube, without a tube, or only after the wheel has been carefully inspected.

For the 1974 MG MGB, the 165R14, 155R14, and 520-14 all share a 14-inch wheel diameter, so they are in the same basic wheel-diameter family. The 1974 MG Midget's 145R13 is different and requires a 13-inch wheel. Diameter compatibility, however, is only one part of the decision, because approved rim widths differ by size and product.

An original MGB wheel may accept more than one of its 14-inch sizes, but you still need to confirm that the wheel width matches the tire you choose. That check is especially important if the car has aftermarket wheels or if the wheel dimensions are not known with certainty. An original Midget wheel should be treated as a separate case because its 13-inch fitment does not cross over to the MGB's 14-inch tire group.

A 1974 MG should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, welders, and other ozone sources that age rubber. Keep the tires properly inflated, move the car occasionally if practical, and avoid leaving it in standing moisture or on dirty concrete for long stretches. Bias-ply tires such as the MGB's 520-14 are more prone to flat-spotting during static storage, while any collector tire can suffer surface cracking if the environment is poor.

If the car will sit for months, rolling it periodically or supporting it in a way that reduces sustained load can help preserve shape and ride quality. Clean storage habits matter just as much as mileage on a lightly used MG. A garage-kept car with careful storage practices often preserves its tires better than a regularly driven car that lives outdoors, even if the tread still looks fresh.

On a 1974 MG, tire life should be judged more by age and condition than by miles driven. A collector tire should be evaluated closely once it reaches about five to seven years of age, and many owners begin serious replacement consideration as the tire approaches ten years, even if tread depth still looks usable. The DOT date code on the tire sidewall is the simplest way to confirm age.

That approach fits the way many MGs are used: short drives, seasonal outings, and long periods of storage. A tire can age out long before it wears out, especially on a lightweight sports car that does not consume tread quickly. If the car is new to you, checking date codes is one of the fastest ways to avoid trusting old rubber simply because it still presents well visually.

Tires on a 1974 MG should be checked before every drive and given a more deliberate inspection before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, foreign objects, and any sign that the tire is losing pressure. On cars using tube-type setups, valve stems and tube-related air loss deserve extra attention because a small issue can become a larger one after sustained highway heat.

Collector cars often spend more time parked than commuting, so problems can develop quietly between drives. A quick walk-around catches obvious trouble, but an enthusiast preparing for a rally, show weekend, or back-road trip should also inspect the spare, pressure-match the set, and make sure the tires have not aged into a condition where appearance is better than actual serviceability.

For a 1974 MG MGB, radial construction was firmly part of the era, and the MGB fitments here include two radial sizes, 155R14 and 165R14, as well as a 520-14 bias-ply alternative. That means an owner researching original-type fitment should think first about period-appropriate construction and size family, not just brand. No single original-equipment brand should be assumed without checking market-specific and trim-specific references.

A careful restoration should compare the tire on the car with period owner literature, road tests, and marque-club guidance, especially if the car has lived in more than one country or has been restored before. The broad rule is straightforward: stay with the correct wheel diameter and an era-appropriate construction style for the car's intended presentation. That gives you a historically sensible starting point without overclaiming a one-size-fits-all original answer.

Yes, correct tire fitment matters on a 1974 MG if the car is being judged for authenticity. Size, construction, and sidewall appearance all affect whether the car looks consistent with its period and intended market presentation. A modern-looking tire with the wrong overall visual character, or a bias-ply or whitewall treatment that does not suit the way the car is being presented, can stand out immediately to knowledgeable judges and MG enthusiasts.

That does not mean every event has the same standard. A driver-class MGB may be judged far more loosely than a high-level concours restoration, and a personalized Midget may not be chasing factory-style accuracy at all. If trophies matter, verify the judging expectations before selecting between the MGB's radial and bias-ply options, and compare sidewall style just as carefully as the size code itself.

For the 1974 MG Midget, the fitment here centers on 145R13, a radial size on a 13-inch wheel. That aligns with the period move toward compact radial fitments on small sports cars, especially for road use in the 1970s. Original-equipment branding should not be assumed from a reproduction tire selection, but the size and radial construction family are the important authenticity markers to start with.

A Midget owner trying to keep the car visually and mechanically consistent should first verify that the car still wears its intended 13-inch wheels. After that, the focus shifts to a tire whose proportions and sidewall appearance suit a small British sports car rather than simply choosing any 13-inch radial. Period brochures, surviving unrestored cars, and MG club knowledge are the best final checks when a restoration is aiming for factory-style accuracy.

1974 MG tires can be appropriate for highway driving when they are the correct size, in sound condition, and used within their rated capability. Some 165R14 and 145R13 products carry H speed ratings, which correspond to 130 mph, and a 155R14 product carries a T rating, which corresponds to 118 mph. Those ceilings are well above normal highway speeds, but age, condition, inflation, and the car's own mechanical state matter just as much as the tire's speed symbol.

On an MG of this era, braking, steering, suspension wear, and wheel condition often become limiting factors before a fresh reproduction tire does. Bias-ply and radial tires also communicate differently on the road, especially in tracking and response, so the car should be driven with that construction in mind. If the tires are old, mismatched, or of uncertain age, solve that first before assuming the car is ready for sustained highway use.

Inflation pressure on a 1974 MG should follow the vehicle's factory recommendation for the car and the tire maker's guidance for the exact tire being used. Where load-and-pressure information appears, 165R14 reaches 1,102 pounds at 51 psi on one product, 155R14 reaches 990 pounds at 44 psi on one product, 520-14 reaches 1,230 pounds at 60 psi on some products, and 145R13 reaches 825 pounds at 44 psi on one product. Those figures are load capacities at stated maximum pressures, not universal settings for every MG.

In practice, the correct running pressure is often lower than a tire's maximum sidewall figure and should be chosen with the car's weight balance and intended use in mind. Do not transfer a pressure from an MGB size to a Midget size, or from a bias-ply MGB setup to a radial MGB setup. Start with the vehicle recommendation, then make small, informed adjustments only if the tire maker's guidance supports it.

Before a longer drive in a 1974 MG, inspect each tire for cracking, cuts, bulges, punctures, uneven wear, and signs of age-related hardening. Confirm cold pressures, verify that the spare is usable, and look closely at valve stems or tube-related hardware if the setup requires tubes. Wheel nuts, wheel condition, and basic alignment symptoms such as a steering pull or feathered wear should also be checked before committing the car to sustained road time.

A longer trip in a classic MG is never only about the tires, but the tires are one of the quickest ways to prevent a roadside problem. Pair the tire check with a broader once-over of brakes, cooling, charging, and fluid levels, since these cars reward preparation. If the car has been sitting, take a short local drive first to feel for vibration, flat-spotting, or pressure loss before heading farther from home.