1958 MG Tire Fitment Guide

1958 MG vehicles use two tire sizes: 155R15 and 560-15. Both sizes apply to the two listed 1958 MG models, MG and MGA, and both mount on 15-inch rims. For 155R15, the listed rim width range runs from 4.00 to 5.50 inches on products where width guidance is given. For 560-15, listed fitments include 4.5-inch rims and a 4.50 to 5.50 inch range depending on the product.

That means the size question for a 1958 MG is less about identifying a unique model-only fitment and more about deciding which construction and appearance suit the car. A radial 155R15 gives you one path, while a 560-15 bias-ply gives you another. Before choosing, verify the actual wheel width on the car and compare it to the tire you are considering, especially if the car has replacement or restored wheels.

On a 1958 MG, 560-15 is a numeric bias-ply size. The 560 is the nominal section-width designation used in period U.S. sizing, and the 15 identifies a 15-inch wheel diameter. It does not read like a modern metric radial size because it belongs to an earlier sizing system commonly seen on mid-century cars and sports cars. In the available offerings for 1958 MG, 560-15 appears only as a bias-ply tire.

That makes 560-15 the straightforward choice for an owner who wants traditional sizing language, vintage construction, and period-looking sidewall options. It is also the size where narrow and wide whitewall variants appear, which matters if the car is being restored to a particular visual style. You still need to confirm the wheel width and decide whether the car’s use leans more toward originality, occasional touring, or event presentation.

On a 1958 MG, 155R15 is a metric radial size. The 155 refers to section width in millimeters, the R indicates radial construction, and the 15 is the wheel diameter in inches. In this older Euro-metric style, the aspect ratio is not written out, but it is conventionally treated as an 80-series radial. The available 1958 MG products in this size are blackwall radials from Firestone and Michelin.

That means 155R15 reads more like a later-era sizing format and points you toward a radial tire rather than a bias-ply one. For many MG owners, that is the key difference because it affects how the car feels on the road as much as how the sidewall looks. Within this size, pay attention to the individual tire’s speed rating and whether it is tube-type or tubeless, since those details are not identical across every 155R15 option.

For a 1958 MG, the choice between 155R15 and 560-15 is mainly a choice between radial and bias-ply construction, not between different model-specific fitments. Both sizes are used across the listed 1958 MG range and both mount on 15-inch wheels. The 560-15 keeps the car in a traditional mid-century bias-ply format, while the 155R15 moves to a radial construction that many owners prefer for regular road use.

Owners restoring a car for period presentation often gravitate toward the 560-15 because the construction and available whitewall treatments suit the era. Owners who expect more frequent driving usually start by looking at 155R15 options instead. Either path can be correct for a 1958 MG, but it helps to decide early whether your priority is historical presentation, regular touring behavior, or a balance between the two.

Sidewall style depends on the size you choose for a 1958 MG. The 155R15 radial offerings are blackwall tires, while the 560-15 bias-ply range includes narrow whitewall and wide whitewall choices from Firestone and US Royal. That gives the bias-ply size more visual variation, especially for owners trying to match a particular late-1950s appearance. The radial size stays more restrained and European in presentation.

For a sports car like a 1958 MG, blackwall is the more understated look and is often the natural direction when a radial tire is desired. Whitewall selection is usually more about style preference and restoration interpretation than mechanical fitment. If the car is headed for judged events, compare the sidewall treatment against period photos, marque references, and the standards used by the club or event where the car will be shown.

Four brands appear in the available tire range for 1958 MG vehicles. In 155R15 radial form, the choices include Firestone and Michelin. In 560-15 bias-ply form, the choices include Firestone and US Royal. That means brand choice changes somewhat with the construction and size you decide to run rather than staying identical across the full tire range.

Michelin is especially familiar in period European radial contexts, while Firestone and US Royal carry strong American vintage-tire recognition for classic bias-ply offerings. The right pick is less about name alone and more about matching the brand’s available size, sidewall style, and construction to your 1958 MG’s intended use. Once you narrow the size, compare the individual tire’s sidewall look, speed rating where stated, and rim-width guidance before finalizing the choice.

Rim width guidance for 1958 MG tires varies by size and sometimes by individual product. In 155R15, listed radial products show a 4.00 to 5.50 inch rim-width range where that specification appears. In 560-15, some products specify a 4.5-inch rim, while others show a 4.50 to 5.50 inch range. All listed sizes share a 15-inch rim diameter, but width still needs to be matched to the tire selected.

That is especially important on older sports cars because wheels may have been changed, restored, or replaced over the years. A 15-inch diameter alone does not guarantee that every tire in both sizes is equally suitable for every wheel on the car. Measure the wheel, check the tire maker’s rim-width recommendation for the exact product, and make sure the wheel’s condition is appropriate before mounting new tires.

Inner-tube use on 1958 MG tires depends on the exact tire chosen. Within the 155R15 radial size, tube status varies by product: Michelin XAS appears as TT, Michelin X and Michelin XAS-FF appear as TL, and other 155R15 listings do not all carry the same marking. The 560-15 bias-ply listings here do not show TT or TL markers in the size description, so the practical decision should be made by checking the specific tire and wheel combination rather than assuming one answer for the whole year and make.

That matters because tube choice is tied not only to the tire but also to the wheel design and condition. Original-style wheels, older rims, or certain restoration setups may call for a different approach than newer replacement wheels. Before mounting, verify the sidewall marking on the exact tire, inspect the wheel for suitability, and replace tube-related hardware such as valve stems when required by the setup you are using.

A 1958 MG can use both listed tire sizes on 15-inch wheels because both 155R15 and 560-15 share the same rim diameter. That said, diameter alone is only part of the fitment picture. The radial listings show a 4.00 to 5.50 inch rim-width range where provided, while the bias-ply listings include 4.5-inch applications and a 4.50 to 5.50 inch range on some products.

In practical terms, many original-size 15-inch wheels can serve as the starting point for either size, but you should still confirm the actual wheel width and condition before mounting. This is especially worthwhile if the car has had wheel work done over the decades or if the wheels are not believed to be original. Matching the tire to the wheel properly helps preserve handling feel and avoids unnecessary fitment surprises.

A 1958 MG should be stored clean, dry, and out of direct sunlight, with the tires kept away from ozone-producing sources such as electric motors, chargers, and some shop equipment. Tire pressures should be maintained during storage, and the car should be moved periodically or supported appropriately if it will sit for a long stretch. Bias-ply tires like 560-15 are more prone to temporary flat-spotting during static storage, while any older-style sidewall can suffer from long exposure to heat, ultraviolet light, and neglect.

Good storage habits matter on a light collector sports car because the tires often age out before they wear out. If your 1958 MG is driven only seasonally, make storage part of routine ownership rather than an afterthought. A breathable car cover, a dry floor, and regular checks for pressure loss or visible cracking will do more for tire life than simply parking the car and forgetting it until the next event.

Tires on a 1958 MG are usually judged more by age than by mileage. A collector-car tire should be evaluated closely once it reaches about five to seven years of service, and replacement often deserves serious consideration by around ten years regardless of remaining tread. The DOT date code on the tire sidewall is the starting point for establishing age. That age-based rule applies whether the car wears 155R15 radials or 560-15 bias-ply tires.

Classic MGs often cover limited annual mileage, so a tire can look usable while still becoming too old for dependable road service. Sidewall condition, how well the tire holds air, the car’s storage environment, and any sign of hardening or cracking all matter as much as tread depth. If the age is uncertain or the tires have sat for years, replacement is usually wiser than trying to stretch more seasons out of them.

A 1958 MG should have its tires inspected before every drive and again before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, lodged debris, and pressure loss. If the setup uses tube-type tires or tubes within the assembly, valve-stem condition deserves special attention as well. Collector cars often spend long periods parked, so deterioration can appear between drives even when mileage is low.

A quick walkaround before starting out can prevent the most common age-related tire surprises. For longer trips, add a pressure check, inspect the spare, and confirm that each tire still feels and looks consistent with the last time the car was driven. On an older sports car, tire inspection is one of the easiest ways to improve confidence before heading out onto roads where traffic speeds may exceed what the car saw in normal period use.

A 1958 MG MGA would originally have been associated with bias-ply construction in period, as radial adoption was still a transition-era subject and varied by market and owner preference. Within the tire choices available here, 560-15 is the period-style bias-ply size and 155R15 is the radial alternative. That makes 560-15 the natural starting point for an owner trying to stay close to the car’s late-1950s character without assigning an unverified original-equipment brand.

Original fitment on a 1958 MG could still vary by market, delivery destination, and long-ago dealer or owner decisions, so event-level authenticity sometimes requires more than picking the right size alone. If the car is being restored for judging, compare your intended tire against factory literature, period photos, and MGA club references. That extra step helps confirm whether construction type and sidewall treatment match the standard expected for your exact restoration goal.

Correct tire fitment absolutely matters when a 1958 MG is being prepared for judged display. Size, construction type, and sidewall style all influence how authentic the car appears, especially on a sports car where the tires are visually prominent. A modern-looking radial blackwall may be perfectly usable on the road, but it can read differently in a concours setting than a period-style bias-ply tire in the proper size and sidewall treatment.

Judging standards are not identical everywhere, so the right answer depends on the event as much as the tire itself. Some shows reward overall era-correct appearance, while others are stricter about construction and visual details. Before committing to a set, check the expectations used by the relevant MG club, registry, or concours body so that the tire complements the level of authenticity you want the finished car to present.

For a 1958 MG in 155R15 radial fitment, Michelin XAS and Michelin XAS-FF are both listed as 155HR15 82H tires, so each carries an H speed rating with a 130 mph ceiling. Both show blackwall styling, radial construction, and a 4.00 to 5.50 inch rim-width range. The practical distinction in the available specifications is tube status: XAS appears as TT, while XAS-FF appears as TL. Their listed weights are the same as well.

That means the decision between the two is not about a different speed class or a different wheel diameter. Instead, it comes down to choosing the product that best matches your wheel setup and your preference for tube-type or tubeless fitment where appropriate. On a 1958 MG with original or restored wheels, that difference can matter more than the shared headline size, so confirm compatibility before settling on one Michelin radial over the other.

1958 MG tires can be suitable for highway use when they are in the correct size, properly mounted, correctly inflated, and matched to the way the car is driven. In the 155R15 radial size, available products include T-rated tires with a 118 mph ceiling and H-rated tires with a 130 mph ceiling. The 560-15 bias-ply listings here do not show speed letters, so they should be approached as traditional vintage-style tires rather than evaluated by modern performance-tire expectations.

On a 1958 MG, tire condition is only part of the safety picture. Brakes, steering, suspension, alignment, and the general realities of a late-1950s lightweight sports car are often more important than the tire’s theoretical speed ceiling during normal highway use. If the car will be driven regularly in modern traffic, choose a size and construction that suit that use, and inspect the whole chassis with the same care you give the tires.

Inflation pressure for a 1958 MG should begin with the vehicle maker’s original recommendation for the car, then be checked against the tire manufacturer’s specifications for the exact tire selected. The available 560-15 bias-ply listings show a maximum load of 970 pounds at 32 psi. One listed 155R15 radial shows a maximum load of 1045 pounds at 44 psi. Those figures are tire ratings, not universal service pressures to copy across every tire or every 1958 MG setup.

That distinction matters because a tire’s maximum rated pressure is not necessarily the same as the pressure that gives the best ride, handling, and wear on the car. Use the vehicle handbook as the first reference, then compare it with the specific tire’s sidewall and manufacturer guidance. Never transfer a pressure number from the radial size to the bias-ply size, or from one product line to another, without confirming that it applies.

Before a longer trip in a 1958 MG, inspect all four tires and the spare for cracking, cuts, bulges, tread damage, and air pressure. Make sure each tire matches the intended setup, especially if the car uses a tube-type configuration or a mixed history of old and newer wheel components. Look closely at valve stems, check for any sign of rubbing or uneven wear, and confirm that the tires are still within a reasonable service age.

A longer-drive inspection should also include the broader systems that matter on an older MG: brakes, steering play, wheel-bearing feel, fluid levels, cooling health, and basic electrical reliability. Tires are your first point of contact with the road, but they work as part of the whole car. Taking a few extra minutes before departure is often the difference between a pleasant touring day and a preventable roadside interruption.