825-20 Tire Size Guide

The 825-20 is a numeric bias-ply size in which the first number represents a nominal section width of 8.25 inches and the number after the dash identifies a 20-inch wheel diameter. It is an older sizing format commonly associated with prewar and early postwar passenger cars and light trucks.

Modern P-metric sizes usually include width in millimeters, an aspect ratio, and a construction letter in the code itself. The 825-20 format does not spell out those details, so buyers need to look beyond the size code for information such as exact load capacity, tube setup, and the way a specific tire will sit on the wheel.

The 825-20 fits a 20.0-inch wheel, which is 508.0 millimeters in diameter. Rim diameter must match exactly, because a tire built for a 20-inch bead seat will not mount correctly on any other wheel diameter.

Wheel width matters too. In this size, the published fitment range runs from 6.50 to 7.00 inches wide, which affects how the tire's sidewall stands and how the tread sits on the road. If you are working with original or specialty wheels, compare both diameter and width before assuming a wheel-and-tire combination is correct.

The 825-20 has a nominal section width of 8.25 inches, which converts to about 209.6 millimeters. Section width refers to the tire's widest point from sidewall to sidewall when mounted and inflated, not the width of the tread that actually contacts the road.

Clearance checks should be based on section width because the sidewall is usually what gets closest to fenders, springs, steering arms, and brake hardware. Tread width can be narrower than the overall casing, so buyers comparing old tire sizes to modern replacements should always look at the full inflated width, not just the footprint.

Yes, 825-20 and 8.25-20 refer to the same basic size designation. The difference is simply how the width is written, with one version showing the decimal point and the other compressing it into older catalog shorthand.

Alias formats such as 82520, 825 20, 825X20, and 8.25X20 can also point to the same size family, but buyers should still confirm the full construction and service details on the tire itself. Vintage notations are not always presented consistently across manufacturers, so the wheel diameter, intended use, and casing type still deserve a careful check.

The 825-20 is commonly a tube-type fitment and is often set up with a tube. Tube use is still a wheel-and-tire-system question rather than a size question, so the final decision should be confirmed against the actual tire, wheel design, and manufacturer guidance.

Many antique and military-style applications use older rim designs where tube fitment is part of the complete assembly, not just the tire size. When replacing old tires, inspect the wheel carefully for condition, bead-seat design, rust, and any signs of previous tube use. Matching the tube setup to the wheel is just as important as choosing the correct nominal size.

The 825-20 weighs between 60 and 70 pounds across the products in this size. Those figures are for the tire alone without the wheel, and the difference reflects variation in casing design and intended service within the same 825-20 fitment.

Tire weight matters more than many buyers expect on antique and truck-based applications. A heavier casing can change steering effort, ride response, and how much unsprung weight the suspension has to manage. When comparing options in the same size, it helps to think about whether the vehicle will be driven lightly, displayed, or used in a more demanding working role.

The 825-20 is associated with antique and prewar to early postwar passenger cars and light trucks that used tall, narrow bias-ply tires on 20-inch wheels. It belongs to an older sizing era in which overall tire proportions were a major part of the vehicle's original appearance and steering feel.

Fitment should be treated as a starting point, not a universal answer, because early vehicles often changed wheel types, axle equipment, or body clearance over time. Original manuals, surviving tire placards, and direct measurement of the wheel and wheel opening remain important when deciding whether the 825-20 is the right size for a particular antique vehicle.

The 825-20 fits wheel widths from 6.50 to 7.00 inches. Staying within that range helps the tire maintain the profile it was designed to have and keeps the casing from being pulled too flat or pinched too tightly.

A narrow wheel can make the sidewalls balloon outward, while an overly wide wheel can flatten the tread shape and alter both appearance and response. On a restoration, those changes can affect more than handling; they can also change how authentic the vehicle looks from the front, rear, and side view once the tire is mounted.

The 825-20 is often a strong period-style choice when an antique vehicle originally used a numeric bias-ply size in this general range. Bias-ply construction is usually more in keeping with prewar and early postwar appearance, including the tall sidewall shape and the steering character many restorers expect.

Authenticity still depends on more than the basic size code. Buyers should compare wheel width, overall proportions, intended use, and any original documentation before assuming every 20-inch antique application called for the same tire. A judged vehicle may require closer attention to size notation, tread style, and the complete wheel-and-tire setup.

The 825-20 uses bias-ply construction, so the driving feel is typically more period-correct than modern in character. Buyers can expect the kind of sidewall behavior and steering response that antique vehicles were originally designed around rather than the more settled feel associated with later radial tires.

Driving impressions also depend heavily on suspension condition, alignment, steering play, and the weight of the vehicle carrying the tire. On a well-sorted antique car or light truck, the 825-20 can preserve the original personality of the vehicle, but it should be chosen with realistic expectations about how early tire designs behave on modern pavement.

The 825-20 can be used on the road when the tire, wheel, and vehicle are all in sound condition and the application matches the tire's intended service. Its bias-ply construction and antique sizing, however, mean the driving experience will be different from that of a modern radial replacement on newer vehicles.

Road use decisions should take into account steering condition, braking system health, load carried, and how the vehicle is actually driven. Buyers planning regular use should inspect wheel condition carefully, confirm that the tire's load capacity is appropriate, and avoid assuming that a vintage-size tire will automatically behave like a modern highway tire.

The 825-20 belongs to a tire family where visual proportion is a major part of the fitment. An 8.25-inch nominal width on a 20-inch wheel creates the tall, narrow look commonly associated with antique passenger cars and early light trucks, so small changes in size or wheel width can noticeably alter the vehicle's posture.

Stance is not just cosmetic. Tire proportion influences fender fill, steering arc clearance, and the way the vehicle sits at rest. On restorations, many owners choose this type of size specifically because the shape of the casing helps preserve the original silhouette, which can be lost quickly if a wider or shorter substitute is installed.

The 825-20 is available from STA. In a specialty vintage size like this, the more important question is usually whether the tire's construction, service category, and wheel compatibility match the vehicle rather than how many brands appear in the catalog.

Brand choice should be considered alongside casing weight, intended use, and whether the tire is aimed at highway service or military and truck-style duty. On an antique vehicle, consistency across the full set also matters, since mixing tread types or construction details can change both the visual presentation and the way the vehicle responds on the road.

A quality 825-20 tire should have the correct bias-ply construction, a size profile that suits the vehicle, and specifications that line up with the wheel and intended service. In this size, weight, load rating, and wheel-width compatibility are especially useful clues because they show how substantial the casing is and what kind of use it was built for.

Buyers restoring an antique vehicle should also think about how closely the tire supports the original look of the car or truck. A good choice is not just one that mounts; it is one that preserves the right proportions, works with the existing wheel, and suits the way the vehicle will actually be driven after restoration.

Yes, keeping all four 825-20 tires matched is the best practice for most antique and light truck applications. Matching construction, tread type, and casing style helps maintain consistent steering feel, braking response, and visual balance from corner to corner.

Mixed tires can introduce differences in diameter, stiffness, and tread character even when the sidewall shows the same nominal size. On a vintage vehicle, those differences may be more noticeable because the suspension and steering systems were designed around narrower bias-ply tires. A uniform set also makes it easier to judge wear patterns and service needs over time.

The 825-20 should be inspected regularly for cracking, cuts, bulges, air loss, uneven wear, and signs that the casing has been stressed by age or load. On antique vehicles, inspection should include both the tire itself and the wheel hardware because older wheel systems can introduce problems that are easy to miss.

Bias-ply tires often spend long periods on vehicles that are driven only occasionally, so time and storage environment matter as much as tread depth. Check the sidewalls, bead area, and tread base before longer drives, and pay attention to any change in steering feel or vibration that could signal a developing issue.

The 825-20 should be stored away from heat, direct sunlight, standing moisture, and ozone sources such as electric motors or battery chargers. If the vehicle sits for extended periods, clean the tires, keep them properly inflated, and avoid leaving them on wet concrete or in areas where temperature swings are severe.

Long storage can age a tire even when the tread still looks usable. Antique vehicles also tend to develop flat spotting when they sit in one position for too long, so moving the vehicle periodically or relieving some load during storage can help preserve ride quality. Storage care is especially important with heavy, tube-type vintage assemblies.

The 825-20 is commonly a tube-type fitment, but tube service should always be confirmed as part of the complete wheel-and-tire system. The condition of the wheel, the design of the rim, and the construction of the specific tire all matter before a tube and flap arrangement is chosen.

When servicing an older assembly, inspect the inside of the wheel for rust, sharp edges, and old repair issues that could damage a tube. Tube-related problems often show up as gradual air loss or sudden failure after mounting, so careful preparation of the wheel is just as important as selecting the correct nominal tire size.

The 825-20 should be replaced when age, cracking, bulges, persistent air loss, impact damage, or casing deterioration raise doubts about roadworthiness, even if tread depth still appears acceptable. Tread alone does not tell the whole story on a vintage bias-ply tire, especially one used on an antique vehicle or stored for long periods.

Time, heat, sunlight, moisture, and inactivity can all weaken an older tire from the inside out. Before any extended drive, inspect the sidewalls and bead areas closely and consider the age of the entire assembly, including tubes and wheel condition. A collector tire that looks presentable can still be due for replacement if the structure is no longer trustworthy.

In this size, a published rating of 4500 pounds at 100 psi appears on one Military & Truck application. That figure must be matched to the specific tire being used, because load capacity is tied directly to the casing design and the inflation pressure stated for that same tire.

Load verification is especially important on vintage trucks, military-style vehicles, and heavy antique builds where visual size alone does not tell you what the tire can support. Buyers should compare axle loads, wheel condition, and intended road use against the actual sidewall markings and service information before putting the vehicle into use.

The most important checks for the 825-20 are tire condition, wheel condition, proper inflation for the specific tire, and confirmation that the 20-inch rim diameter and 6.50 to 7.00 inch wheel width are correct for the assembly. On an older tube-type setup, the tube and related wheel components deserve the same attention as the outer casing.

Before a longer trip, inspect for cracking, sidewall damage, uneven wear, missing hardware, and signs of bead-seat corrosion on the wheel. Buyers should also review current sidewall markings and make sure the vehicle is not being asked to carry more weight than the mounted tire is rated to support at its specified pressure.