1931 Reo Tire Fitment Guide

1931 Reo vehicles use three different tire sizes, and each size is tied to a specific model. The 1931 Reo 30 & 35 Series uses 650-18, the 1931 Reo Flying Cloud uses 6.50-17, and the 1931 Reo Royale uses 700-18. The 30 & 35 Series and Royale both use 18-inch rims, while the Flying Cloud uses a 17-inch rim. Where published fitment products exist, 650-18 fits 3.25- to 3.50-inch rims and 700-18 fits 3.75- to 4.00-inch rims.

That means the first fitment check on a 1931 Reo is always the model name, not just the year. A buyer with an 18-inch wheel still needs to distinguish between the smaller 650-18 fitment and the larger 700-18 fitment, since those belong to different cars in the lineup. Confirm the actual wheel diameter and compare the existing tire markings before moving on to sidewall style or restoration preferences.

On a 1931 Reo tire, 650-18 is an early numeric bias-ply size. The 6.50 portion refers to the tire's nominal section width, and the 18 refers to the wheel diameter in inches. For 1931 Reo applications, that size belongs to the 30 & 35 Series. It is not a radial metric size and it does not encode a modern aspect ratio the way later passenger-car sizing does.

Reading the code correctly helps prevent one of the most common prewar fitment mistakes: matching the wheel diameter but missing the intended overall size and profile. On a 1931 Reo 30 & 35 Series, 650-18 points you toward an era-correct bias-ply tire shape and wheel fitment. Once the size is confirmed, the next decision usually comes down to appearance, such as blackwall versus whitewall styling.

No, 1931 Reo models do not all use the same tire size. The 30 & 35 Series uses 650-18, the Flying Cloud uses 6.50-17, and the Royale uses 700-18. That split reflects the differences in model positioning within the Reo lineup, from more accessible cars to larger and more premium offerings. Even among the 18-inch applications, the size itself changes by model.

For a buyer or restorer, that means year and make are only the starting point. A 1931 Reo owner should verify the exact model badge, body tag, and wheel diameter before selecting a tire. If the car has changed hands many times or has undergone restoration work, it is also wise to compare the wheel and current tire markings against the model-specific fitment before finalizing a replacement.

1931 Reo tire sidewall style depends on the size. For 650-18, available styles include Blackwall and Wide Whitewall. For 700-18, available styles include Blackwall, Wide Whitewall, and Double-Whitewall. All of the currently listed choices are bias-ply tires, which suits the prewar character of the Reo lineup and keeps the visual profile in line with the era.

Sidewall style matters most when you are deciding how authentic or formal you want the finished car to look. A blackwall typically gives a simpler, more utilitarian presentation, while whitewall and double-whitewall treatments create a more dressed appearance often associated with higher-end restoration tastes. The right choice usually follows the model's character, the market the car would have served, and the standards of the shows or tours you plan to attend.

Firestone is the brand represented in the currently available 1931 Reo fitments covered here. The listed 650-18 tires are Firestone Balloon models, and the 700-18 offerings include Firestone Balloon and Firestone Classic Bias Ply lines. All are bias-ply constructions appropriate to an early-1930s American car. Brand choice here is therefore less about comparing multiple manufacturers and more about choosing the specific size and sidewall presentation that fits your model.

That makes the buying process for a 1931 Reo more straightforward than on some later collector vehicles. Instead of sorting through many brands, you can focus first on the correct fitment for your model and then refine the look of the car through blackwall, whitewall, or double-whitewall styling where available. Owners seeking strict show authenticity may still want to compare their chosen series and sidewall treatment with period photos and marque-club guidance.

For 1931 Reo applications in 700-18, Firestone Balloon and Firestone Classic Bias Ply share the same nominal size, the same 18-inch rim diameter, the same 3.75- to 4.00-inch rim-width range, and the same listed maximum load of 1520 pounds at 36 psi where that figure appears. The visible differences in the current offerings come down mainly to series and sidewall presentation, with Blackwall, Wide Whitewall, and Double-Whitewall versions available in the Balloon line and a Blackwall option in the Classic Bias Ply line.

For a Royale owner, that means the practical choice is largely visual unless you are matching a specific restoration theme. If you want a fuller whitewall treatment, the Balloon line gives more appearance options. If you want a simpler blackwall presentation in the same basic size and load class, either series can fit the brief, subject to verifying the wheel and the finished look you want on the car.

Published rim-width guidance exists for two of the 1931 Reo sizes covered here. The 650-18 tire used on the 1931 Reo 30 & 35 Series fits rims from 3.25 to 3.50 inches wide, while the 700-18 tire used on the 1931 Reo Royale fits rims from 3.75 to 4.00 inches wide. Both are 18-inch applications, but they do not use the same rim-width range, which is an important distinction during restoration or wheel replacement.

A buyer should measure the actual wheel before assuming that any 18-inch prewar Reo rim is interchangeable across models. Correct rim width supports proper tire shape, bead seating, and overall stance. If the car has aftermarket wheels or mixed parts from another Reo model, verify both the wheel diameter and width before selecting a tire, especially when moving between the 30 & 35 Series and the larger Royale.

The listed 1931 Reo fitments are early bias-ply tires, but inner-tube status is not marked the same way modern passenger tires often are. On a prewar application like a 1931 Reo, tube use should be confirmed against the specific wheel type, the tire's sidewall marking, and the intended setup rather than assumed from size alone. That matters most on original-style wheels, where the wheel construction itself often drives the decision.

Before mounting tires on a 1931 Reo, inspect the wheels for condition, rust scale, rivets, and sealing surfaces, and confirm whether the chosen tire is meant to run with a tube. If the car is being rebuilt after long storage, replace valve components and review the wheel carefully instead of reusing old hardware. Prewar fitment rewards caution, because the wheel and the tire have to work as a system.

No, the original 1931 Reo wheels should not be treated as universal across all three tire sizes. The 30 & 35 Series and Royale both use 18-inch wheels, but their tire sizes differ and their published rim-width ranges differ as well. The Flying Cloud uses a 17-inch wheel, so its fitment is separate from the two 18-inch applications. Wheel diameter alone is only part of the compatibility question on a prewar car.

A restorer working with mixed parts should identify the exact model before reusing a wheel set. Even where diameter matches, the wrong width can alter the mounted tire shape and compromise the intended fit. If the car's history is unclear, compare the existing wheels against known measurements and the current tire markings before assuming that a wheel from one 1931 Reo model will suit another.

A 1931 Reo should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone sources that age rubber. Keep the tires properly inflated, roll the car periodically if possible, and avoid letting it sit for long periods on a damp floor. Bias-ply tires are especially prone to temporary flat spotting and sidewall aging when they remain stationary for extended stretches.

For seasonal or long-term storage, many collectors either move the car a short distance every few weeks or take some weight off the tires with stands placed correctly under the chassis. The goal is not to leave the suspension hanging, but to reduce prolonged tire distortion. A simple storage routine makes a noticeable difference in how smoothly a 1931 Reo comes back into service after sitting.

Tires on a 1931 Reo should be judged more by age and condition than by mileage, because collector cars often see limited road use. A sensible rule is to evaluate them closely once they reach about five to seven years of age and to treat around ten years as a serious replacement point regardless of tread depth. The DOT-style date code on later reproduction tires helps establish age, while overall rubber condition remains the more important guide.

A prewar car can look lightly used and still be riding on old tires that have hardened or begun to crack. Check sidewalls, tread blocks, and the area around the bead for age-related deterioration, not just wear. If the history of the tires on a 1931 Reo is unclear, age-based caution is usually wiser than trying to stretch service life on a car that may spend most of its time parked.

Tires on a 1931 Reo should be inspected before every drive and again before any longer outing or tour. Look for sidewall cracking, tread separation, cuts, bulges, uneven wear, and pressure loss, and inspect the spare at the same time rather than treating it as an afterthought. On a prewar car, the wheel hardware and valve area also deserve regular attention because age affects the whole assembly, not just the tread.

Frequent inspection matters because collector cars often spend more time parked than running, and static storage can hide problems until the first road use. A quick walk-around before each drive helps catch aging rubber, loose caps, or low pressure before they become a roadside issue. Building that habit into ownership is one of the simplest ways to keep a 1931 Reo dependable for local drives and longer events.

A 1931 Reo 30 & 35 Series would originally have used bias-ply tires, because bias-ply construction was standard for American passenger cars of that period. The model-specific fitment used here is 650-18, mounted on 18-inch wheels. That size places the car squarely within normal early-1930s practice, when numeric bias-ply sizing and tall sidewall proportions defined ride height and appearance.

For restoration work, the safest path is to keep the correct model-specific size and then choose the sidewall treatment that matches the car's intended presentation. If you are building for judged events, consult marque specialists or period literature to confirm whether a blackwall or whitewall look best suits your body style and market. The size and construction matter first, while finer cosmetic choices often vary by trim and owner preference.

Correct tire fitment matters on a 1931 Reo because show judging and serious restoration review often consider size, construction type, and sidewall appearance as part of the car's overall authenticity. On a prewar American car, an incorrect wheel diameter, the wrong numeric size, or a sidewall treatment that clashes with the car's era can stand out immediately. Even outside formal judging, the wrong tire can change the visual balance of the body and fenders.

That does not mean every event uses identical standards, so it helps to match the car to the level of authenticity you want to achieve. Touring owners may accept a visually appropriate tire that suits their presentation goals, while concours entrants should verify the details against marque-club guidance and period references. On a 1931 Reo, the right tire is a major part of getting the stance and period impression correct.

For the 1931 Reo Royale in 700-18, Firestone Balloon and Firestone Classic Bias Ply occupy the same basic fitment space rather than representing a change in size. Both use an 18-inch rim, both fit 3.75- to 4.00-inch rim widths, and both carry the same listed maximum load of 1520 pounds at 36 psi where that specification appears. The most visible distinction in the current range is sidewall presentation, since the Balloon line includes whitewall variants while the Classic Bias Ply option is shown in Blackwall form.

From an authenticity standpoint, the choice depends on the look you are trying to recreate on the car. A simpler blackwall treatment can support a restrained touring-car appearance, while whitewall options can suit a more formal or dressed presentation. When building a judged 1931 Reo, compare the chosen sidewall style with period photos, body style, and event standards rather than assuming every attractive period tire treatment is equally appropriate.

1931 Reo tires in the sizes covered here are bias-ply tires designed for a prewar vehicle, and they can be suitable for normal road use when they are correctly fitted, properly inflated, and in sound condition. The available listings here do not show modern speed-letter ratings for these sizes, so the larger safety question on a 1931 Reo usually extends beyond the tires themselves to the car's age, braking system, steering, suspension, and overall mechanical condition.

On a car from 1931, safe highway use is less about chasing modern cruising expectations and more about respecting the vehicle's original design envelope. Bias-ply tires track and respond differently than modern radials, and the rest of the car was engineered around that behavior. Before any sustained higher-speed driving, make sure the entire chassis is sorted and that the tires are recent, matched, and free from age-related deterioration.

Inflation pressure for a 1931 Reo should follow the factory recommendation for the car and the pressure limits associated with the specific tire size you are using. In the currently listed products, 650-18 appears with a maximum load of 1205 pounds at 36 psi, and 700-18 appears with a maximum load of 1520 pounds at 36 psi. Those figures are tire ratings, not blanket instructions to inflate every 1931 Reo tire to 36 psi in service.

The best practice is to begin with the original vehicle recommendation when available and then confirm that your chosen reproduction tire is being used within its rated limits. Pressure should never be transferred casually from one size or model to another, especially on a lineup like 1931 Reo where three different fitments are involved. Consistent pressure checks matter more on a collector car because long storage can slowly reduce inflation without obvious visual warning.

Before a longer drive in a 1931 Reo, inspect every tire for sidewall cracking, cuts, bulges, embedded objects, irregular wear, and proper inflation, and do the same for the spare. Check the valve stems and wheel condition, and make sure the tires are the correct size for the model because this year Reo used three different fitments across the passenger-car range. A pre-drive inspection should also include brakes, steering play, wheel bearings, fluids, and cooling system condition.

Longer drives expose weaknesses that may not appear on short local trips, especially on a car that spends much of its life stored. A careful once-over helps you catch aging rubber and mechanical issues before heat and distance make them worse. For touring use, many experienced owners also carry basic tire-service tools and confirm that the jack, spare, and inflation equipment are usable before leaving home.