400/425-15 Tire Size Guide

The 400/425-15 is a vintage numeric tire size with two nominal width figures and a wheel diameter. In this code, 4.00 and 4.25 refer to the narrow width range historically associated with the size, and 15 identifies the wheel diameter in inches that the tire is built to fit.

Unlike a modern P-metric size, the 400/425-15 does not directly spell out aspect ratio, construction, or service description in the size itself. Buyers reading this format are looking at an earlier sizing system used on classic passenger cars, so wheel diameter, actual section width, tube setup, and the intended restoration style matter more than trying to read it like a newer radial code.

The 400/425-15 fits a 15-inch wheel, which is 381.0 millimeters in diameter. The wheel diameter must match exactly, because a tire built for a 15-inch rim will not seat correctly on any other rim diameter.

Wheel width matters too. This size appears on a 3.00-inch rim in the products shown, which reinforces how narrow the original wheel and tire package is compared with later passenger-car fitments. When working with an older restoration, check both the rim diameter and the actual wheel width before mounting the tire, especially if the car has replacement wheels or later brake and suspension changes.

The 400/425-15 has a section width of 4.00 inches, which is 101.6 millimeters. Section width is measured at the widest point of the inflated tire from sidewall to sidewall, not across the tread face.

Clearance checks should be based on section width rather than tread width because the sidewall is usually the first part that approaches fender edges, steering arms, or suspension pieces. On a narrow vintage fitment like the 400/425-15, that measurement also helps preserve the original visual balance of the car, especially when the goal is to maintain a tall, slender bias-ply profile instead of a wider modern look.

Yes, 400/425-15 and 40042515 refer to the same tire size. The difference is only how the size is written, with one version using separators and the other compressing the characters into a single string.

Older tire sizes often appear in several catalog and search formats, including versions with spaces, slashes, or no punctuation at all. What matters is matching the actual size designation, wheel diameter, and intended construction. When comparing listings, make sure the tire is still the same 400/425-15 vintage numeric fitment rather than a similarly written size with different proportions or a different wheel requirement.

The 400/425-15 is commonly a tube-type fitment. On older bias-ply sizes like this one, tube use is often part of the wheel-and-tire system rather than something the size code alone can settle with complete certainty.

Original-style wheels, rim condition, and the exact tire design all affect whether a tube is appropriate. Many antique and early postwar vehicles used wheel designs that were built around tube service, so it is wise to confirm tube use against the actual wheel and tire being installed. For restoration work, that check matters both for proper air retention and for keeping the assembly aligned with the car's intended setup.

The 400/425-15 tire shown here weighs 20 pounds. That figure refers to the weight of one tire by itself, without the wheel.

Tire weight matters because it contributes to unsprung weight, which influences how an older suspension reacts over bumps and at lower road speeds. On a narrow vintage bias-ply size, keeping the assembly close to the intended proportions can help preserve the steering effort and ride character expected from the period. If you are balancing authenticity with drivability, tire weight is one more detail worth comparing along with construction and wheel size.

The 400/425-15 is associated with classic passenger cars from the 1940s to early 1960s. Its narrow width and bias-ply construction place it in the earlier automotive period, where tall, slim tire proportions were part of normal factory appearance and driving feel.

Vehicle fitment still needs to be confirmed one car at a time. Original owner literature, wheel measurements, and physical clearance at the front suspension and fender openings all matter, especially on cars that may have had wheel swaps or brake work over the years. Treat the size as a strong historical starting point rather than an automatic answer for every vehicle from that era.

Yes, the 400/425-15 is the kind of bias-ply size commonly chosen when the goal is a factory-style restoration on an earlier passenger car. Its narrow profile and vintage numeric sizing are much closer to the original look than a wider modern replacement would be.

Authentic restoration work involves more than matching the size code alone. Wheel width, wheel design, sidewall appearance, and the way the tire sits in the wheel opening all influence whether the finished car looks right for the period. If the vehicle will be judged on originality, compare the tire choice against factory literature or proven restoration references before finalizing the setup.

Start by confirming a 15-inch wheel diameter and a 3.00-inch wheel width, since that is the wheel specification shown with this size. Those dimensions affect how the tire seats, how the sidewall stands, and whether the overall profile remains true to the intended vintage shape.

Installation planning should also include bead-seat condition, rim straightness, brake clearance, and fender clearance at full steering lock if the tire is going on the front axle. Because the 400/425-15 is often used with older wheels and tube-type practice, the wheel itself is just as important as the tire. A correct size on the wrong wheel can still create mounting or service problems.

The 400/425-15 uses bias-ply construction, so its driving character is tied to the flexible, period-style feel classic car owners expect from earlier tire designs. On a properly sorted vintage chassis, that usually means a more traditional steering response and a ride quality that matches the car's original suspension tuning.

Modern drivers should remember that much of the on-road feel comes from the full vehicle system. Suspension wear, alignment settings, wheel condition, and the age of the tire all influence how the car tracks and responds. A bias-ply setup is often chosen for authenticity first, so the experience should be judged against vintage expectations rather than late-model passenger-car behavior.

The 400/425-15 can be appropriate for vehicles that are being kept close to their original character, but buyers should approach it as a vintage-size bias-ply fitment rather than a modern everyday replacement. Its appeal is tied more to correct proportions and period driving feel than to contemporary tire design priorities.

Road manners on current streets depend heavily on the condition of the steering system, suspension bushings, alignment, and the driver's expectations. Before regular use, inspect the full wheel-and-tire setup carefully and keep speeds, load demands, and trip length in line with the condition of the vehicle. For many classic owners, this size is best understood as part of an older driving package, not as a substitute for a modern touring radial.

The 400/425-15 belongs to an earlier sizing era, and its narrow width gives it the tall, slim visual character associated with 1940s to early 1960s passenger cars. That appearance is one reason restorers choose this size instead of moving to a wider later tire that can visually overpower a small-bodied car.

Proportion affects more than looks. A narrow vintage tire changes how the car fills the wheel opening, how the steering feels at low speed, and how closely the finished stance resembles an original-period setup. On older vehicles, those visual and dynamic details are often part of the charm, so preserving the intended profile can matter as much as the raw dimensions themselves.

Excelsior is available in the 400/425-15 size. For a narrow vintage fitment like this, brand selection is usually only one part of the decision, with construction style, wheel compatibility, and restoration goals carrying just as much weight.

Buyers comparing options in a specialty size should look closely at how faithfully the tire matches the intended application. On an early passenger-car restoration, consistency of dimensions, correct bias-ply construction, and a sidewall treatment that suits the vehicle's era often matter more than simply choosing by name alone. Matching all four tires as a set is also important for uniform appearance and handling.

A quality 400/425-15 tire should first match the original style of the vehicle and the wheel it will be mounted on. In this size, that means paying close attention to true bias-ply construction, narrow vintage proportions, and compatibility with a 15-inch wheel and 3.00-inch width.

Craftsmanship matters most when the tire is being used on a restoration where visual accuracy is part of the goal. Even small differences in profile, sidewall shape, or overall stance can change how an early car looks once it is on the ground. Buyers should also inspect current sidewall markings and confirm that the full set shares the same construction and appearance so the car sits evenly and predictably.

Not every restoration calls for a blackwall, even though blackwall is one of the sidewall treatments available in this size. The right choice depends on the car's trim level, delivery year, and the visual finish you are trying to recreate.

Factory-correct appearance can vary within the same general era, so sidewall style should be checked against period photos, sales literature, or established restoration references. A blackwall can be exactly right on some builds and visually out of place on others. For collectors aiming at a faithful presentation, sidewall appearance deserves the same attention as the size code and construction type.

The 400/425-15 should be stored the way any vintage bias-ply tire should be stored: away from direct sunlight, heat sources, standing moisture, and ozone-producing equipment such as electric motors or battery chargers. Clean, dry conditions help slow the aging that can affect even low-mileage collector tires.

If the vehicle sits for long periods, inspect the tires regularly for cracking, air loss, flat spotting, and changes in sidewall shape before returning the car to service. Movement and proper inflation checks are part of good storage practice as well. A tire can retain usable tread and still age out from time, environment, and inactivity, especially on a car driven only occasionally.

The 400/425-15 should be inspected before regular driving and especially before longer trips. Look for cuts, bulges, weather cracking, irregular wear, and any loss of air pressure, since early-style tire and wheel systems deserve closer routine attention than many newer daily-driver setups.

Inspection should include the wheel and, where applicable, the tube-related service condition of the assembly rather than the tread alone. On a classic car, long periods of sitting can hide problems until the vehicle is back on the road. Frequent visual checks and prompt correction of alignment or wheel issues help the tire wear more evenly and preserve the way the car drives.

The 400/425-15 is commonly a tube-type fitment, but the final decision should be made from the actual wheel and tire combination being used. Older wheel design, bead condition, and the specific tire construction all influence whether tube service is appropriate.

Confirmation is especially important on restorations where original wheels may have been refinished, repaired, or replaced over time. Check the tire's current sidewall markings, inspect the wheel's bead area, and follow manufacturer guidance for the complete assembly. When there is any doubt, a qualified tire professional familiar with vintage wheels can help prevent air-retention and installation problems.

The 400/425-15 should be replaced when age, cracking, bulges, repeated air loss, or other condition problems appear, even if the tread still looks deep. Vintage-size tires on collector vehicles often accumulate age long before they accumulate mileage, so visual tread depth alone is not enough.

Replacement decisions should be based on the tire's full condition and the way the car is used. Before any road trip, inspect the sidewalls, tread area, and wheel condition closely. Older cars also deserve a check of steering and suspension health, because instability blamed on the tire can sometimes start elsewhere. When condition is questionable, err on the side of caution and have the assembly evaluated.

Before driving on the 400/425-15, confirm that the tire is mounted on the correct 15-inch wheel, that the wheel width suits the tire, and that there is no visible cracking, bulging, or air loss. On an older setup, wheel condition and bead-seat integrity are just as important as the tire itself.

Tube service should also be verified against the actual wheel-and-tire assembly, since this size is often used in tube-type applications. For road use, buyers should inspect the car as a system by checking alignment, brake clearance, and suspension condition along with the tires. Those steps do not guarantee performance, but they do reduce the chance of preventable fitment and service issues.

No tire size should be treated as automatically acceptable for every road-use situation simply because it fits the wheel. The 400/425-15 is a specialty vintage size, so buyers should review current sidewall markings, confirm the intended use of the tire, and check local requirements where registration or inspection rules apply.

Suitability also depends on the condition of the tire, the wheel it is mounted on, and the demands being placed on the vehicle. A collector car driven occasionally to local events has different needs than one expected to cover long interstate distances. Verifying wheel compatibility, tire condition, and the vehicle's actual operating demands is the practical way to approach safe use.