700-20 Tire Size Guide

The 700-20 is a numeric tire size. In this code, 7.00 refers to the nominal section width in inches, and 20 identifies the wheel diameter in inches. On this size, the tire is built for a 20-inch rim and carries the tall, narrow proportions typical of late 1920s and early 1930s bias-ply fitments.

Unlike a modern P-metric size, the 700-20 does not directly show an aspect ratio, load index, or speed symbol in the code itself. Buyers have to confirm those details from the actual tire being considered. That simpler sizing format is part of why antique tires need to be evaluated by wheel diameter, width, construction type, and intended vehicle use together rather than by the size code alone.

The 700-20 tire fits a 20-inch wheel, which is 508.0 millimeters in diameter. The rim diameter must match exactly, because tire beads are engineered for one specific wheel diameter and will not seat correctly on a different size.

Wheel width matters too. In this size, products span wheel widths from 3.75 to 5.50 inches depending on the specific tire. A narrower wheel changes the tire’s profile, and a wider wheel changes it in the opposite direction, so the same 700-20 size can behave differently across different rims. Check the actual wheel on the vehicle and compare it to the tire’s approved width range before installation.

The 700-20 has a nominal section width of 7.0 inches, which equals 177.8 millimeters. Section width is measured at the widest point of the inflated sidewall, not across the tread face that contacts the road.

Clearance work should be based on section width, because the sidewall bulge is often what comes closest to fenders, frame rails, steering arms, or brake components. Tread width is usually narrower and can give a false sense of available space. On antique cars and early trucks, where wheel wells and steering geometry can vary, section width is the number to compare first when checking fit.

Yes, 700-20 and 7.00-20 refer to the same basic size designation. The decimal point is a notation difference rather than a change in fitment, and buyers will also see this size written as 70020, 700X20, or 7.00X20.

The important step is to look past the way the size is printed and confirm the actual wheel diameter, construction type, and tire application. Antique tire naming was not always as standardized in everyday use as modern sizing, so alternate spellings are common. When comparing options, make sure the full tire specification matches the vehicle’s needs rather than assuming every similar-looking size code means the same tire.

The 700-20 is commonly a tube-type fitment and is often set up with a tube. That said, tube use is a wheel-and-tire-system question rather than a size question, so the final decision should be confirmed against the actual tire and the wheel being used.

Early wheels, lock-ring designs, and restoration-era rim conditions can all affect whether a tube is appropriate. A buyer should also consider the wheel’s age, bead seat condition, and how the tire is intended to be used. On antique vehicles, getting the tube decision right matters for both reliability and authenticity, so it is worth confirming with the tire manufacturer or an experienced vintage tire professional.

In this size, passenger-car versions weigh from 30 to 40 pounds, while Military & Truck versions run from 32 to 46 pounds. Tire weight can vary even within the same 700-20 size because sidewall design, carcass construction, and intended vehicle duty all influence the finished tire.

Weight matters because it affects unsprung mass, steering effort, and how a vintage suspension responds over rough pavement. A heavier truck-oriented tire may be appropriate for a vehicle that truly needs that service profile, but it changes the feel compared with a lighter passenger version. For a restoration, it makes sense to compare weight alongside load rating, wheel width compatibility, and the vehicle’s original use.

The 700-20 was used on select large prewar American passenger cars and some light-truck-type applications, with documented use from 1926 through 1933. It is most closely associated with bigger luxury, touring, and upper-series vehicles that originally ran tall bias-ply tires on 20-inch wheels.

Original fitment history is useful, but it should not be treated as a blanket interchange rule. Vintage chassis often saw wheel changes, brake updates, or mixed replacement practices over the decades. Use the known vehicle history as a starting point, then verify the actual wheel diameter, wheel width, fender clearance, and service needs of the specific vehicle before deciding that the 700-20 is the right fit.

Wheel width is very important with the 700-20 because products in this size span a wide approved range from 3.75 to 5.50 inches. The tire may still share the same 20-inch bead diameter, but its mounted shape and footprint can change noticeably depending on which wheel width it is installed on.

A narrow wheel tends to pull the sidewalls inward and can make the tire appear taller and rounder, while a wider wheel spreads the casing and changes the stance. Those shifts matter on antique vehicles where steering clearance, wheel-opening fill, and judged appearance all count. Measure the wheel that is actually on the car or truck, not just what you expect should be there from the factory.

For many antique vehicles from the late 1920s through the early 1930s, the 700-20 is a strong period-appropriate size when the original wheel and chassis setup call for it. Its bias-ply construction, tall sidewall shape, and 20-inch format match the visual character and road manners expected from that era.

Restoration accuracy still depends on more than size alone. Sidewall treatment, wheel width, vehicle weight, and intended use all shape what looks and functions correctly on a finished car. Owners preparing a high-authenticity restoration should compare the installed wheel setup and surviving factory documentation before choosing among passenger or truck-oriented versions of the 700-20.

The 700-20 usually delivers the tall-sidewall, bias-ply driving character expected from an antique vehicle. That often means a softer initial ride over small road irregularities, slower steering response than a modern radial, and a more period-authentic feel at the wheel, especially on large prewar chassis.

Driving feel also depends on wheel width, suspension condition, alignment, and the actual load carried by the vehicle. A passenger version on a correct wheel can feel noticeably different from a truck-oriented version in the same size. Owners should judge the 700-20 as part of the whole vehicle system rather than expecting one size designation to guarantee a single road manner.

A 700-20 remains an antique bias-ply fitment, so buyers should expect behavior that reflects the road design and vehicle engineering of its era rather than modern touring-tire manners. Steering response, tracking, braking feel, and lane-following can all differ from what drivers are used to in later radial-equipped vehicles.

Modern road use calls for realistic expectations and a careful mechanical check. Suspension wear, steering play, brake condition, and tire age can influence the experience as much as the size itself. Drivers planning regular road miles should inspect the full chassis and keep speeds appropriate to the tire’s construction, the vehicle’s setup, and the condition of the roads being used.

Yes, a passenger-oriented 700-20 and a Military & Truck-style 700-20 can feel different even though they share the same nominal size. Differences in carcass weight, load rating, and intended service can change steering effort, ride harshness, and the way the tire responds under an older vehicle.

Passenger versions in this size weigh from 30 to 40 pounds, while Military & Truck versions run from 32 to 46 pounds, so there can be a meaningful change in unsprung weight and casing stiffness. Matching the tire to the vehicle’s actual role matters more than choosing by size code alone. A correct service type usually gives a more satisfying result than simply selecting the heaviest construction available.

The 700-20 is available from BFGoodrich, Denman, and Firestone. Those names give buyers several directions within the same size, including passenger-oriented antique tires and heavier-duty truck-type versions that share the 700-20 designation but serve different kinds of vehicles.

Brand choice should start with the vehicle’s purpose rather than the name on the sidewall alone. Compare construction type, sidewall treatment, wheel width compatibility, and load rating before deciding. On a restoration, visual character matters too, so a buyer should also think about whether a blackwall, wide whitewall, or double whitewall better suits the vehicle’s original trim and intended presentation.

A quality 700-20 should first match the vehicle’s real needs in size, construction, wheel fit, and load capability. In an antique fitment like this, the best choice is not simply the most expensive or most decorative version, but the one that aligns with the vehicle’s weight, wheel width, and period-correct use.

Buyers should also compare consistency across the full set. Mixing very different service types, sidewall styles, or load ratings can change both appearance and driving behavior. For a serious restoration, it is wise to look at casing weight, approved wheel range, and whether the tire is aimed at passenger-car use or truck service. Those details tell you more about suitability than brand name alone.

The right sidewall style in 700-20 depends on the vehicle’s original trim level, the era being restored, and how formal or utilitarian the finished car should appear. Blackwall versions suit plainer presentations, while wide whitewall and double whitewall versions deliver a more upscale prewar look.

Appearance should still be matched with fitment details. A whitewall tire that looks right but carries the wrong load profile or wheel-width requirement is not automatically the better choice. Restoration-minded buyers often decide sidewall style after confirming the correct service category first, then choosing the finish that best complements the wheel, body color, and trim level of the vehicle.

The 700-20 should be inspected regularly for cracking, weathering, cuts, bulges, and uneven wear, even if the vehicle is driven only on limited outings. Antique tires can age from time, heat, sunlight, ozone exposure, and long stationary periods just as much as they wear from mileage.

Collector vehicles benefit from simple habits: check inflation before use, inspect the sidewalls after storage, and look for changes in ride height or steering feel that might suggest an air-loss issue. If the vehicle sits for long stretches, keep it stored away from direct sunlight and electric motors that generate ozone. Occasional movement can also help reduce prolonged flat spotting.

The 700-20 should be inspected before every extended drive and periodically during the driving season, especially on a low-mileage antique vehicle. Tread depth alone is not enough on an older bias-ply tire, because visible cracking, hardening, bulges, or signs of prior repairs can matter more than remaining tread.

A thorough inspection includes the outer sidewall, inner sidewall if accessible, tread surface, valve area, and the wheel itself. Early vehicles often put unusual loads on tires because of steering geometry, braking systems, and long storage cycles. If anything looks questionable, have the tire and wheel evaluated before road use rather than assuming a good-looking tread surface means the assembly is ready to go.

The 700-20 is commonly a tube-type fitment, but tube use should still be confirmed from the actual tire and wheel combination. The condition and design of the wheel matter just as much as the size, particularly on antique rims that may have been restored, repaired, or altered over time.

When a tube is appropriate, the whole assembly needs to be considered together, including the tire casing, flap requirements where applicable, and the wheel’s bead and drop-center condition. Owners should avoid assuming that every 700-20 setup is identical simply because the printed size matches. A vintage tire professional can help confirm the proper approach before mounting and inflation.

The 700-20 should be replaced when age or condition raises concern, even if the tread still appears usable. Cracks in the sidewall, exposed fabric, bulges, repeated air loss, impact damage, or severe hardening are all stronger warning signs on an antique bias-ply tire than tread depth alone.

Time and storage conditions matter because many vehicles using this size are driven infrequently. A tire can retain a presentable appearance and still be past the point where it inspires confidence on the road. Before tours, club events, or longer drives, inspect each tire closely and consider the age of the whole set rather than judging only by the amount of visible tread.

Load rating is critical with the 700-20 because capacities vary widely within this one size. Passenger products in this size range from 1700 lb at 36 psi to 1980 lb at 42 psi, while a Military & Truck version is rated at 3150 lb at 90 psi.

Those differences show why size alone is not enough to select a safe replacement. Buyers should match the tire to the vehicle’s actual axle loads, wheel suitability, and intended service rather than assuming every 700-20 carries the same weight. If the vehicle has been modified or used for heavier touring duty, rechecking tire selection against current operating conditions is especially important.

The most important checks before driving on the 700-20 are tire condition, inflation, wheel compatibility, and visible signs of age or damage. On an antique fitment, buyers should also pay close attention to the wheel itself, since tube use, bead seating, and rim condition all affect how the assembly performs in service.

Before any longer trip, inspect for cracks, cuts, bulges, and uneven wear, then confirm that the installed tire matches the wheel diameter and approved wheel-width range for that specific version. Roadworthiness also depends on the rest of the vehicle. Steering looseness, brake issues, and poor alignment can all make an older bias-ply setup feel worse than it should, so the tire should be evaluated as part of the full chassis.