1958 NSU Tire Fitment Guide

1958 NSU vehicles in this guide use two tire sizes: 125R12 and 440-12, and both apply to the 1958 NSU Prinz. Each size mounts on a 12-inch rim, so the difference is not wheel diameter but tire type and period. The 125R12 is a radial, while the 440-12 is a bias-ply size. A listed rim-width range appears for one 125R12 application at 3.0 to 4.0 inches.

That means a 1958 NSU owner should start by deciding whether the car is being restored for a more original visual character or set up for regular driving with radial construction. Since both sizes share the same rim diameter, the next step is checking the actual wheel width and matching the tire to the intended use of the Prinz. If the car has changed hands or wheels over the years, verifying what is physically on the car before ordering is especially worthwhile.

On a 1958 NSU, 440-12 is a numeric bias-ply size. The 440 indicates the tire's nominal section width in the older numeric system, and the 12 is the rim diameter in inches. Unlike a metric radial code, it does not use modern width-and-aspect-ratio formatting. That older sizing convention is exactly what many European and American cars of the period used before radial notation became more familiar to modern buyers.

For a 1958 NSU Prinz, 440-12 is the size to consider when the goal is a more authentic late-1950s appearance and a traditional bias-ply look. It is available in both blackwall and narrow whitewall form, so you can also tune the visual presentation without changing the basic construction. If originality matters for a restoration, this size will usually make more historical sense than a later-style radial code.

On a 1958 NSU, 125R12 is a euro-metric radial size. The 125 is the nominal section width in millimeters, the R identifies radial construction, and the 12 is the rim diameter in inches. Because no aspect ratio is printed in the code, it follows the conventional profile associated with this early euro-metric style. The available 1958 NSU products in this size carry an S speed rating and are tubeless.

That makes 125R12 the more modern-feeling fitment in the 1958 NSU range, even though it still suits a period small European car. It is available in blackwall and narrow whitewall versions, so owners are not locked into one appearance. If your Prinz will be driven regularly and you prefer radial construction, this size is the one to examine first, while still confirming wheel width and overall clearance on the actual car.

For a 1958 NSU Prinz, the choice between 125R12 and 440-12 is mainly a choice between radial and bias-ply construction, since both fit 12-inch rims. The 125R12 is a radial available from Michelin, while the 440-12 is a bias-ply available from BFGoodrich. The radial route generally suits owners who want more modern road behavior, while the bias-ply route suits owners who want a more period-correct presentation for a late-1950s small car.

That decision should reflect how the Prinz will actually be used. A show-focused restoration usually leans toward the vintage-style bias-ply size, especially if the car is judged on era authenticity. A driver-oriented car often leans toward the radial size, particularly for longer secondary-road use. Since both are 12-inch fitments, verify wheel width and make sure the car's current wheels have not been changed from original practice before making the final call.

1958 NSU tires are available in both blackwall and narrow whitewall styles across the two listed sizes. In 125R12 radial form, Michelin offers both a blackwall and a narrow whitewall. In 440-12 bias-ply form, BFGoodrich also offers both a blackwall and a narrow whitewall. That gives the Prinz owner flexibility to choose a more understated factory-type look or a slightly dressier period presentation.

For a modest German economy car of 1958, blackwall generally reads as the simplest and most utilitarian appearance, while a narrow whitewall adds a touch of period flair without looking excessive. The right choice depends on the visual character of the restoration and the market style you want to emulate. If the goal is authenticity for a judged car, compare your selected sidewall style against marque references and period photos before committing.

Two brands cover the listed 1958 NSU sizes. Michelin offers the 125R12 radial products, while BFGoodrich offers the 440-12 bias-ply products. That split follows the two different construction paths available for the 1958 NSU Prinz rather than multiple brands competing within the same exact size here. Each brand also offers more than one sidewall style within its size.

The practical result is that brand choice and size choice are linked on this year and make. If you want the radial 125R12 route, you are looking at Michelin products; if you want the numeric bias-ply 440-12 route, you are looking at BFGoodrich products. That makes it especially important to decide first whether authenticity or a more modern radial driving feel is the priority, because the brand follows that decision.

A 1958 NSU Prinz uses 12-inch rims with either of its listed tire sizes, 125R12 or 440-12. A stated rim-width range appears for the 125R12 radial at 3.0 to 4.0 inches. The 440-12 bias-ply products are also built for 12-inch rims, but the key fitment detail consistently shared across both sizes is the 12-inch diameter. Wheel width still matters, even when rim diameter is correct.

That is why a 1958 NSU owner should inspect the actual wheel before choosing between the radial and bias-ply options. Cars this old are often running replacement wheels, refinished originals, or parts sourced over decades of ownership. If the wheel width falls within the stated range for the radial, that supports the 125R12 option; if you are pursuing the bias-ply size, matching the wheel to the intended vintage-style setup remains an important final check.

1958 NSU tube requirements depend on the size and product selected. The listed 125R12 Michelin radial products are marked TL, which means tubeless. The 440-12 BFGoodrich bias-ply products are not marked TL in the available size description, so they should be treated as a traditional fitment that deserves careful confirmation against the wheel and the specific tire's sidewall marking before installation. Older small-car wheels sometimes introduce their own considerations beyond the tire alone.

For a 1958 NSU Prinz, the important step is to match the tire construction to the wheel condition and wheel type already on the car. A tubeless-marked radial still depends on a sound rim and valve setup, while a vintage-style bias-ply fitment may call for more attention to how the wheel is prepared. If there is any doubt, inspect the wheel carefully and verify the exact sidewall marking of the tire being used rather than assuming every 12-inch product is handled the same way.

Both listed 1958 NSU Prinz tire sizes mount on 12-inch rims, so the original wheel diameter is compatible with both 125R12 and 440-12. That is the main point of overlap between the two sizes. The larger fitment question is wheel width and wheel condition, especially when moving between a modern radial format and an older bias-ply format. Diameter compatibility alone does not answer every setup question.

For most owners, that means the original 12-inch wheels are the logical starting point, but they still need to be checked before switching constructions. The safest approach is to confirm the actual wheel width, inspect bead seats and valve areas, and make sure the wheels are sound after decades of use or storage. If your Prinz has been modified at any point, do not rely on appearance alone; verify the wheel itself before fitting either size.

A 1958 NSU should be stored in a cool, dry, dark space away from direct sunlight, electric motors, welders, battery chargers, and other ozone-producing equipment that can accelerate sidewall aging. Keep the tires clean, maintain proper inflation, and avoid parking the car for long periods on damp ground. Bias-ply tires like the 440-12 tend to develop flat spotting more readily during long static storage, while any vintage-style tire can suffer from age-related cracking if the environment is poor.

Moving the 1958 NSU periodically or supporting it appropriately during long-term storage helps reduce stress on the casing. If the car will sit for a season, check pressure before and after storage rather than assuming it stayed stable. Radials and bias-ply tires age differently in service feel, but both benefit from the same collector-car storage habits: stable temperature, clean surfaces, and protection from light, moisture, and ozone.

On a 1958 NSU, tire life should be judged more by age and condition than by mileage. Collector vehicles often accumulate very few miles, but the rubber still hardens, the casing still ages, and the sidewalls still deteriorate over time. A sound rule is to begin evaluating collector-car tires closely once they are around five to seven years old and to treat the ten-year mark as a serious replacement point regardless of tread depth. The DOT date code on applicable tires helps establish age.

That matters especially on a light, low-use car like the 1958 NSU Prinz, where old tires can look deceptively healthy because they have not worn much. Sidewall checking, stiffness, recurring air loss, or vibration are all reasons to inspect more closely. A fresh-looking tread pattern does not override age. If the car's history is uncertain, confirming how old the tires actually are is one of the smartest first steps before putting meaningful road time on the car.

Tires on a 1958 NSU should be inspected before every drive and again before any longer outing. Look for sidewall cracking, cuts, bulges, uneven wear, objects in the tread, and signs that the tire is not holding pressure properly. On a vintage car, even small changes are worth noticing early because the vehicle is light, the tires are narrow, and age can affect the rubber more than mileage. Valve stems also deserve close attention as part of every inspection.

A longer drive in a 1958 NSU Prinz is much easier to enjoy when the inspection routine is consistent and disciplined. Check the spare as well, since a decades-old spare is often forgotten until it is needed. If the car uses a vintage-style setup that depends on tube-related components or older wheels, include those pieces in your routine rather than focusing only on tread depth. A few minutes in the garage can prevent a roadside problem that was visible in advance.

For a 1958 NSU Prinz, bias-ply construction is the historically typical starting point for original-equipment thinking, since late-1950s small cars were still commonly delivered on bias-ply tires even as radial technology was gaining ground in Europe. In the available fitments, 440-12 represents that traditional bias-ply style, while 125R12 represents the radial alternative. Both are 12-inch sizes appropriate to the Prinz's wheel diameter, but only the bias-ply option aligns directly with the older construction type associated with the era.

If originality matters, begin with the 440-12 bias-ply path and then compare sidewall appearance against period references for your market version of the car. Factory practice could vary by market, dealer, and production timing, so marque clubs and period literature remain the best way to confirm what is correct for a specific restoration. A radial may still suit a driver-focused Prinz, but it answers a different goal than strict historical presentation.

Correct tire fitment matters on a 1958 NSU because judges and knowledgeable enthusiasts often notice tire size, construction type, and sidewall appearance immediately. On a car from this period, a bias-ply tire in the appropriate vintage-style sizing usually looks more historically consistent than a later-style radial code. Even when the wheel diameter is right, a visibly modern construction or the wrong sidewall treatment can change the character of the car in a way that stands out at a show.

For a 1958 NSU Prinz being prepared for concours or marque-level judging, tire selection should be treated as part of the restoration, not as an afterthought. Blackwall versus narrow whitewall can matter visually, and the same is true of radial versus bias-ply construction. If the event has strict authenticity expectations, check its judging standards and compare them with NSU club guidance before fitting tires. That extra homework often prevents an otherwise excellent restoration from losing points on details.

For the 1958 NSU Prinz, the main difference between blackwall and narrow whitewall offerings is visual presentation rather than basic fitment. Both the 125R12 radial and the 440-12 bias-ply are available in blackwall and narrow whitewall form, so the sidewall treatment can be chosen independently within each size. Blackwall gives the car a simpler, more utilitarian appearance, while a narrow whitewall adds a period accessory-style look that can make the little NSU appear slightly more formal.

That choice should be guided by the restoration theme and the personality you want the car to project. A restrained factory-style presentation often favors blackwalls, especially on economy cars, while a narrow whitewall can be attractive on a more polished or show-oriented build. Because both styles exist in each size, you do not have to change from radial to bias-ply, or vice versa, just to get the sidewall look you want. It is one of the more flexible choices on this year and make.

1958 NSU tires can be suitable for highway use when they are the correct size, in sound condition, and matched to the car's intended use. The listed 125R12 radial products carry an S speed rating, which means a 112 mph ceiling. The 440-12 bias-ply products do not list a speed rating in the available size marking, so they should be approached with the more conservative mindset appropriate to vintage bias-ply construction. On a car like the Prinz, the vehicle's age, brakes, suspension, and overall mechanical condition are at least as important as tire capability.

In practical terms, a well-prepared 1958 NSU on fresh, correctly fitted tires can be enjoyable on modern roads, but it should never be treated like a new car. Keep speeds sensible, allow extra stopping distance, and make sure the steering and wheel bearings are in good order before longer trips. Tire age matters just as much as tire type here. A newer radial may suit regular road use well, while an older-style bias-ply setup calls for more traditional expectations from the driver.

Inflation pressure for a 1958 NSU should be set with the specific tire and the car's factory guidance in mind, not by borrowing a pressure number from another size or another vehicle. The listed products here identify size, construction, and in the case of 125R12, load and speed marking, but tire pressure should still follow the recommendation appropriate to the Prinz and the exact tire being used. Radial and bias-ply tires should never be assumed to want the same operating pressure simply because they share a 12-inch rim.

The best approach is to start with the original owner's manual or a trusted NSU reference, then compare that recommendation with the tire manufacturer's rated guidance for the exact product you are fitting. That keeps the decision tied to both the car and the tire rather than to generic vintage-car advice. Once set, check inflation regularly, because a lightly driven collector car can sit long enough for a small pressure loss to become a real handling and wear issue.

Before taking a 1958 NSU on a longer drive, inspect all four tires and the spare for cracking, cuts, bulges, tread separation, visible aging, and proper inflation. Verify that valve stems are in good condition, and pay close attention to any tire that has been sitting for a long period without use. Since the 1958 NSU Prinz can be fitted with either radial or bias-ply tires, it is also wise to make sure the car feels stable and consistent at lower speeds before committing to a longer route.

Tires are only one part of the pre-drive checklist on a car of this age, but they are among the easiest parts to inspect thoroughly before leaving home. Confirm wheel fastener tightness, look underneath for leaks, and make sure the jack and spare arrangement are usable if needed. A long drive in a vintage NSU is far more enjoyable when the car has been checked methodically, because small issues on a lightweight classic can become noticeable quickly once the miles add up.