600-20 Tire Size Guide

The 600-20 is a numeric tire size in which the first number represents a nominal section width of 6.0 inches and the number after the dash identifies a 20-inch wheel diameter. In plain terms, it is a narrow vintage tire built to fit a 20-inch rim and commonly associated with antique bias-ply applications.

Modern P-metric sizes usually include width in millimeters, an aspect ratio, construction letter, and rim diameter, all in one code. The 600-20 format is simpler and more traditional, but it leaves out several details buyers now expect to see immediately, such as a stated aspect ratio or service description. With an antique size like this, the exact tire chosen matters because load rating, wheel-width range, and intended use can vary within the same size.

The 600-20 fits a 20-inch wheel, which equals 508.0 millimeters at the bead seat. That wheel diameter must match exactly, because tire beads are engineered for one specific rim diameter and will not seat correctly on a different size.

Wheel width matters too. In this size, the products span rims from 2.75 to 5.00 inches wide depending on the version, which is a broad range because passenger, truck, and racing-oriented tires are all present. A restorer should check both the wheel diameter and the actual wheel width before ordering. Using the right width helps preserve intended sidewall shape, steering response, and the period-correct stance that antique vehicles depend on visually.

The 600-20 is 6.0 inches wide in section width, which equals 152.4 millimeters. Section width is the tire’s broadest sidewall-to-sidewall measurement when mounted and inflated, and it is the standard width figure buyers use when comparing vintage sizes.

Tread width is usually narrower than section width, so the number that matters most for clearance is the full sidewall width. On an antique car or light truck, that is the measurement to compare against fender openings, steering arms, springs, and brake hardware. Even when two old-size tires appear similar, a small change in section width can alter rub points, wheel-opening fill, and how closely the tire matches original visual proportions.

Yes, 600-20 and 6.00-20 refer to the same tire size in ordinary vintage tire notation. Buyers also commonly encounter variants such as 60020, 600 20, 600X20, and 6.00X20, which are alternate ways of writing the same basic size.

The differences are usually formatting, not fitment. Older catalogs, sidewalls, and vehicle records were not always consistent about decimal points, spaces, or whether a dash or X separated the numbers. What matters is confirming that the tire is still a 6.0-inch nominal-width, 20-inch-rim size and then checking the actual tire’s wheel-width range, load rating, and intended use. That becomes especially important here because passenger, truck, and racing versions all exist in the same size.

The 600-20 is commonly a tube-type fitment, which is typical of many antique bias-ply applications using older wheel designs. Tube use is still a wheel-and-tire-system question rather than a size question alone, so the final decision should be confirmed against the exact tire and wheel being used.

Collectors should inspect the wheel construction, bead seat condition, valve-hole setup, and any manufacturer guidance before assembly. An older rim may have been designed around tube use even when the size itself seems straightforward, and a reproduction tire may have its own mounting guidance. Getting that detail right helps with air retention, serviceability, and long-term reliability, especially on vehicles that spend long periods parked before being driven again.

The 600-20 ranges from 19 to 32 pounds per tire across the versions offered in this size. That spread reflects the fact that the size appears in passenger, truck, and vintage racing forms rather than one single construction emphasis.

Tire weight affects more than shipping. A heavier carcass adds unsprung weight and can subtly change how an antique vehicle rides and steers, while a lighter racing-oriented tire may suit a very different use case than a roadgoing passenger or truck tire. When comparing two 600-20 options, weight should be considered alongside wheel-width compatibility, load rating, sidewall style, and whether the vehicle is being restored for touring, display, or specialized use.

The 600-20 is most closely associated with antique and prewar to early postwar passenger cars and light trucks. It belongs to the vintage numeric bias-ply family, so it is usually considered in the context of older vehicles that originally used tall, narrow tires on large-diameter wheels.

Fitment should still be treated as vehicle-specific rather than assumed from size alone. Original manuals, wheel markings, surviving tire placards, and restoration documentation are all worth checking before choosing a 600-20. Many vehicles from that era used similar-looking sizes, and the differences can affect ride height, fender clearance, steering effort, and whether the finished stance looks authentic once the car is back on its wheels.

Rim width is a major part of 600-20 tire fitment because the products in this size span wheels from 2.75 to 5.00 inches wide. That range is unusually broad, so the tire must be matched to the actual wheel and the intended use rather than selected by size code alone.

A narrow passenger wheel, a truck wheel, and a racing wheel can all be 20 inches in diameter yet require different tire profiles once mounted. On the correct rim width, the sidewall shape looks right and the tire carries itself as intended. On the wrong rim, the profile can appear pinched or stretched, which changes clearance, steering feel, and the visual correctness that matters on an antique restoration.

The 600-20 is often a strong period-style choice when an antique vehicle originally used this same vintage numeric bias-ply size. Bias-ply construction generally preserves the look, stance, and driving character expected from prewar to early postwar vehicles more faithfully than a later-format substitute would.

Originality-minded buyers should still verify the exact factory tire size, wheel width, and sidewall treatment used on their specific vehicle. A size can be historically appropriate in broad terms but still differ from what a particular car or light truck carried when new. Judged restorations, touring cars, and drivers built for regular road use may each call for a slightly different decision even when they start from the same 600-20 fitment.

A 600-20 bias-ply tire typically delivers the firmer tracking, taller sidewall movement, and more vintage steering feel that owners expect from antique vehicles. It supports an authentic driving character, but it will not behave exactly like a later radial-format tire designed for more modern suspension tuning and road habits.

Road feel depends on more than construction alone. Suspension condition, alignment, wheel width, inflation, load carried, and the age of the tire all influence how the vehicle behaves. On a properly sorted antique chassis, many owners prefer the original-style response because it matches the era. Buyers who expect modern steering precision or lane-holding on contemporary pavement should go into the decision understanding that a bias-ply tire preserves character rather than disguising it.

The 600-20 usually produces the tall-sidewall ride quality associated with antique bias-ply fitments, with a cushioned visual profile and an unmistakably early-era road feel. Because this size is narrow and mounted on a large 20-inch wheel, much of the ride character comes from sidewall shape and carcass construction rather than tread width.

Comfort will vary by the exact version selected. Passenger, truck, and racing-oriented 600-20 tires do not deliver the same response, even though they share the same basic size code. A heavier-duty tire can feel different from a passenger fitment, and a racing-oriented version serves a different purpose altogether. Matching the tire to the vehicle’s actual use matters as much as matching the size, especially on older suspension systems.

The 600-20 can be used on present-day roads when it is the correct size and type for the vehicle, but buyers should treat it as an antique bias-ply fitment rather than expect modern-tire behavior. Steering feel, braking response, and straight-line tracking will reflect the vehicle’s original design and the tire’s older construction style.

Before regular road use, inspect the full setup closely. Tire condition, wheel condition, tube arrangement, alignment, brake performance, and actual load carried all matter. Long interstate trips ask more of an antique vehicle than short local drives, so owners should be realistic about speed, heat buildup, and stopping distance. A freshly restored car on correct 600-20 tires can be enjoyable to drive, but it still needs period-aware expectations and careful preparation.

The 600-20 is available from BFGoodrich, Firestone, and US Royal. Those names cover a mix of blackwall, whitewall, passenger, truck, and specialized vintage racing interpretations within the same basic size.

Brand choice should start with the vehicle’s purpose rather than the name alone. A restored touring car, a light truck, and a race-inspired build may all use 600-20, but they do not need the same carcass weight, wheel-width range, or load-and-pressure rating. Buyers get better results by comparing the complete specification set and selecting a matched set that supports the same handling balance, stance, and appearance at all four corners.

A quality 600-20 tire starts with accurate sizing, proper bias-ply construction, and a specification set that suits the vehicle’s actual use. Wheel-width compatibility, load-and-pressure rating, casing weight, and intended application all deserve attention because this size spans passenger, truck, and racing versions.

Appearance matters too on antique vehicles. A blackwall can be right for some builds, while a wide whitewall may be more appropriate for others, but the visual decision should not come at the expense of fitment. Serious buyers also compare how consistently a full set is built, whether all four or five tires share the same specification family, and how closely the finished stance matches the original look they are trying to preserve.

The 600-20 is offered in both blackwall and wide whitewall versions, and the right choice depends mainly on the vehicle’s original trim level and restoration goal. Sidewall style changes the visual character of an antique vehicle immediately, even when the underlying size remains the same.

Factory-correct presentation should guide the decision whenever authenticity matters. Some restorations look right only with a wide whitewall, while others are more faithful in blackwall form. Beyond appearance, buyers should still confirm that the selected tire carries the right load-and-pressure rating and fits the correct wheel width for the vehicle. A tire can look perfect in profile and still be the wrong functional choice if its intended application does not match the build.

The 600-20 should be stored the same way any collector tire should: clean, properly inflated, shielded from sunlight, and kept away from heat, moisture, and ozone sources such as electric motors or battery chargers. Long periods of sitting can affect an antique bias-ply tire even when tread wear is minimal.

Storage conditions matter because aging is not just about miles. Rubber hardens over time, and flat spotting can develop if a vehicle remains parked in one position for too long. Owners who store a prewar or early postwar vehicle seasonally should inspect the sidewalls and tread before returning it to service, and they should confirm that the tube-and-wheel setup remains sound before any extended drive.

The 600-20 should be inspected regularly for cracking, weathering, bulges, cuts, irregular wear, and air loss, especially before longer drives. Antique vehicles often see lower annual mileage, but time, storage conditions, and infrequent use can age a tire significantly even when the tread still looks serviceable.

Inspection should include the complete wheel-and-tire assembly, not just the tread surface. Check valve stems, wheel condition, sidewall shape, and signs that the tire is not seated or wearing evenly. Bias-ply tires also reward attention to suspension and alignment because those systems influence how the tread contacts the road. Catching a small condition issue early is far easier than dealing with a damaged tire after it has been driven warm.

The 600-20 is often set up with a tube, but tube use should always be confirmed from the actual tire, the wheel design, and the guidance tied to that specific combination. The size points buyers in the right direction, yet the final answer depends on the complete assembly rather than the size code alone.

Old wheels vary widely in construction and condition, which is why this check matters so much on antique applications. A correct tube-and-rim arrangement helps with air retention and reliable service, while a mismatch can create avoidable problems during mounting or use. When there is any doubt, have the wheel inspected and confirm the proper components before the tire is put into regular road service.

The 600-20 should be replaced when it shows cracking, separation, bulges, repeated air loss, exposed cords, or age-related hardening that compromises serviceability. Tread depth alone is not enough to judge an antique tire, because time, storage, and heat can weaken the casing long before the tread appears worn out.

Replacement timing matters even more on vehicles that sit for long periods between drives. A bias-ply tire can look acceptable at a glance yet still be unsuitable for road use once the rubber has aged. Before any tour or event, inspect the full set and compare condition across all tires, including the spare if it may be used. If condition or age is in question, a qualified tire professional should evaluate the assembly.

Load ratings are essential in the 600-20 size because the same size appears in several distinct duty types. Passenger versions in this size are rated from 1,350 lb at 36 psi to 1,400 lb at 50 psi, while the Military & Truck version is rated at 1,820 lb at 60 psi.

Those figures should never be treated as interchangeable. An antique passenger car, a light truck, and a specialized build may all use a 600-20, but they do not place the same demands on the tire. Buyers should match the tire’s actual rating to the vehicle’s weight, loading pattern, and intended road use, then confirm that the wheel itself is appropriate for the pressure and width required by that tire.

The key checks for the 600-20 are tire condition, wheel condition, correct 20-inch rim diameter, proper wheel width, load suitability, and confirmation of the tube setup being used. Those are the fundamentals that determine whether an antique tire-and-wheel assembly is ready for present-day driving conditions.

Modern roads usually mean higher sustained speeds, more heat, and harder braking demands than many antique vehicles originally faced in normal service. Buyers should also review the current sidewall markings on the exact tire they are using and inspect the vehicle before longer trips. Local rules and road-use expectations can vary, so it is wise to confirm the complete setup carefully rather than assume that any 600-20 is appropriate for every old-car application.