1928 Cunningham Tire Fitment Guide

1928 Cunningham vehicles use two tire sizes: 33X6.75 and 700-21, and both are associated with the 1928 Cunningham 8. The 700-21 size fits a 21-inch rim, with listed products covering rim widths from 3.00 to 4.00 inches depending on the tire. The 33X6.75 size follows antique diameter-by-section sizing, where the first number is overall tire diameter rather than wheel diameter.

That means a 1928 Cunningham owner should verify the car's existing wheel and tire fitment before choosing between the two sizes. Since the two sizes are not simply alternate versions of the same 21-inch fitment, the key question is what is already on the car and whether the restoration is being kept to its present specification. Checking the wheel itself, the current tire markings, and any surviving factory or coachbuilder records will usually point you in the right direction.

33X6.75 is an antique diameter-by-section tire size used on 1928 Cunningham fitments. In that format, 33 refers to the tire's approximate overall diameter in inches, while 6.75 refers to nominal section width. It is a bias-ply style size from the brass and early pre-war tire tradition, where tire dimensions were often expressed by outside diameter instead of wheel diameter.

That older sizing method matters because it does not decode the same way a later numeric size does. A 1928 Cunningham owner should not assume that a 33X6.75 tire cross-references directly to a 700-21 just because both are period bias-ply sizes used within the same year and make. If your car currently carries a diameter-by-section tire, preserving the wheel fitment, stance, and body-to-tire proportion usually starts with staying inside that same sizing family.

700-21 is a numeric bias-ply tire size used on 1928 Cunningham vehicles. In this format, 7.00 is the nominal section width and 21 is the wheel diameter in inches. For 1928 Cunningham, currently listed 700-21 tires are all bias-ply products, and the available versions fit 21-inch rims with rim-width ranges spanning 3.00 to 4.00 inches depending on brand and series.

That makes 700-21 more familiar to many collectors because the rim diameter is stated directly in the size itself. If your 1928 Cunningham already uses 21-inch wheels, this size gives you a clearer path to comparing available blackwall and whitewall options. It is still worth matching the tire to the actual wheel width and the look you want for the car, since sidewall treatment can change the finished appearance significantly even within the same numeric size.

A 1928 Cunningham owner should choose between 33X6.75 and 700-21 by matching the tire to the wheel and existing fitment on the car, not by treating them as interchangeable styles. Both are bias-ply sizes, so the decision is not about bias-ply versus radial behavior. It is about preserving the correct period sizing system and making sure the tire matches the wheel diameter and proportions your Cunningham 8 was set up to use.

If your car is already fitted with 21-inch wheels and a 700-21 tire, staying there keeps the search straightforward because there are multiple available products in that size. If your car uses the larger 33X6.75 antique format, the priority is maintaining that specific fitment and appearance rather than substituting by guesswork. A close inspection of the current tire markings, wheel dimensions, and restoration records is the smartest first move before selecting a replacement.

1928 Cunningham tires in 700-21 are available in Blackwall, Wide Whitewall, and Double-Whitewall styles. Firestone offers blackwall, wide whitewall, and double-whitewall versions in that size, while Michelin is represented with a blackwall offering. All of those listed choices remain within period-style bias-ply construction, so the appearance difference comes from sidewall treatment rather than a change in tire type.

Sidewall style can dramatically change how a 1928 Cunningham presents, especially on a large luxury automobile where tire visual mass is part of the car's overall character. Blackwalls tend to read more restrained and technical, while whitewall treatments give a more formal, upscale pre-war look. If you are restoring for authenticity, match the sidewall style to the era, body style, and show standards you are pursuing rather than choosing solely by personal taste.

Firestone and Michelin both appear in the currently available 700-21 offerings for 1928 Cunningham vehicles. Firestone is represented by its Balloon series in blackwall, wide whitewall, and double-whitewall form, while Michelin appears with the Double Rivet in blackwall form. All listed products for that size remain bias-ply tires intended for period-correct fitment on a pre-war luxury car.

Brand choice on a 1928 Cunningham often comes down to the appearance and specification mix you want rather than a change in basic construction type. Firestone gives the broadest sidewall presentation range in the current 700-21 selection, while Michelin offers a distinct vintage-style alternative in the same size. Once the size is confirmed, comparing brand, sidewall style, and rim-width compatibility will usually narrow the field more effectively than brand name alone.

For 1928 Cunningham fitments in 700-21, listed rim-width requirements vary by product. Firestone Balloon versions call for 3.75 to 4.00-inch rims, while the Michelin Double Rivet in 700-21 fits 3.00 to 3.75-inch rims. All of those tires share a 21-inch rim diameter, but the acceptable wheel width changes with the specific tire design.

That means wheel width should be checked before settling on a brand or sidewall style, even after the size itself is confirmed. A Cunningham owner moving between products within the same 700-21 size should treat rim width as part of the fitment decision, not an afterthought. Matching the tire to the actual wheel helps preserve proper profile, steering response, and bead seating on a large, heavy pre-war car.

The currently listed 1928 Cunningham products do not carry tube-type or tubeless markings in the size field, so tube status is not expressed uniformly across the visible offerings. On a pre-war bias-ply luxury car such as a 1928 Cunningham, tube use is commonly tied to the wheel design as much as the tire itself. Early multi-piece or riveted wheels often require tube-compatible setup even when the tire description does not spell it out.

A Cunningham owner should confirm the wheel construction before assuming a tube decision. If the car still uses original-style rims, tube and flap requirements may be part of the correct setup, and valve stem compatibility should be checked at the same time. This is a good point to involve a shop familiar with early collector wheels, because correct assembly matters just as much as choosing the right tire size.

A 1928 Cunningham should be stored in a cool, dry, dark space away from direct sunlight, electric motors, battery chargers, furnaces, and other ozone-producing equipment. Bias-ply tires are especially sensitive to long static periods, and they can develop temporary flat-spotting more readily than modern radials when a heavy collector car sits in one place. Clean floors, stable temperature, and protection from moisture help preserve both the rubber and the wheel finish.

Moving the car slightly from time to time or supporting it appropriately during extended storage can reduce stress on the tire carcass. Tire pressure should be kept at a healthy storage level rather than left low, since underinflation while parked adds sidewall strain. If the Cunningham is stored for a full season, include the spare in the same routine so it is not forgotten until the day it is actually needed.

Tire life on a 1928 Cunningham is usually judged more by age than by mileage, because many collector cars are driven infrequently. A good rule is to begin close inspection once tires are around five to seven years old and to treat about ten years as a serious replacement consideration regardless of remaining tread. The DOT date code, overall rubber condition, and any signs of age-related cracking all matter more than odometer use alone.

A large pre-war luxury car can place substantial load on its tires even during occasional use, so old rubber should not be kept in service simply because it looks barely worn. If the car sees tours, highway stretches, or formal events far from home, age becomes even more important than tread depth. Rechecking the spare's date and condition is part of the same process, since spare tires on collector cars are often much older than the four on the ground.

Tires on a 1928 Cunningham should be inspected before every drive and again before any longer outing. Look for sidewall cracking, bulges, exposed cord, irregular wear, cuts, embedded debris, and any loss of pressure. On an older wheel-and-tire setup, it is also wise to inspect valve stems and the condition of any tube-related hardware during regular service intervals.

Frequent inspection matters because a low-use collector car can age tires quietly between drives. A short local run may not reveal a developing sidewall issue that becomes serious at road speed after the tires warm up. Making inspection part of the pre-drive routine is one of the simplest ways to protect both the car and its occupants, especially on a heavy 1928 Cunningham that asks a lot from period-style bias-ply tires.

A 1928 Cunningham 8 would have been fitted with bias-ply tires in period-correct sizing, not modern radial construction. The year-and-make fitment range here includes both 33X6.75 and 700-21, which reflects the kind of early luxury-car variation that could exist with body style, wheel choice, or restoration history. No specific original-equipment tire brand should be assumed solely from current replacement offerings.

For an owner pursuing a historically faithful restoration, the best path is to confirm the size already associated with the individual car and then select a bias-ply replacement that preserves the proper look and wheel fitment. If the car is being judged, marque clubs, period sales literature, and surviving photographs can help narrow whether blackwall or whitewall presentation is appropriate. Size, construction, and visual profile all matter more than simply finding a tire that mounts.

Correct tire fitment matters on a 1928 Cunningham because judges and knowledgeable enthusiasts often notice tire size, construction type, overall profile, and sidewall treatment immediately. On a prominent pre-war luxury car, tires are a major visual element, and an incorrect sizing family or visibly modern construction can change the stance enough to stand out. Whitewall style versus blackwall presentation may also influence how authentic the finished restoration appears.

That does not mean every event uses the same standard, but it does mean tire choice should be made with the car's intended judging environment in mind. A Cunningham prepared for formal concours display may call for a different appearance than one restored primarily for touring. Before finalizing a tire, compare your planned size and sidewall style with period references and the standards of the club or event where the car will be shown.

For 1928 Cunningham in 700-21, Firestone Balloon and Michelin Double Rivet are both bias-ply options, but they differ in presentation and wheel-width compatibility. Firestone Balloon appears in blackwall, wide whitewall, and double-whitewall form and fits 3.75 to 4.00-inch rims, while Michelin Double Rivet is offered as a blackwall and fits 3.00 to 3.75-inch rims. Listed Firestone examples also carry a max load figure of 1930 pounds at 40 psi on the versions where that specification is shown.

That makes the comparison less about one being universally superior and more about matching the tire to the wheel and the finished look of the car. If your Cunningham uses a narrower 21-inch rim, the Michelin fitment range may line up more naturally. If you want broader sidewall-style choice or are matching a formal whitewall presentation, the Firestone Balloon family gives more visual options within the same basic size.

1928 Cunningham tires can be suitable for road use when they are the correct size, in sound condition, properly inflated, and matched to the wheel, but they remain period-style bias-ply designs. No speed ratings are shown in the currently listed 1928 Cunningham products, so a conservative approach is appropriate. On a car of this age, braking capability, steering geometry, suspension condition, and overall mechanical health are often just as important to safe highway use as the tire itself.

That practical reality means owners should think of highway use as a whole-vehicle question rather than only a tire question. A freshly inspected Cunningham on good bias-ply tires can be an enjoyable touring car, but it should still be driven with respect for pre-war handling and stopping distances. If the car has been sitting or is newly acquired, a thorough mechanical inspection should come before any extended road trip.

Inflation pressure for 1928 Cunningham tires should follow the vehicle's factory guidance where available and the tire maker's specifications for the exact product being used. In the currently listed 700-21 range, certain Firestone Balloon versions show a maximum load of 1930 pounds at 40 psi. That figure should be treated as the rated load-and-pressure point for that tire, not automatically as the universal running pressure for every 1928 Cunningham tire.

Collector-car tire pressure should never be copied casually from one size or brand to another, especially when multiple period fitments exist within the same year and make. The car's weight distribution, wheel setup, and intended use all influence the final pressure choice. Start by matching the size exactly, then compare the tire's own specification with the original owner's guidance and tune within that range as needed for proper wear and road behavior.

Before a longer drive in a 1928 Cunningham, inspect each tire for cracking, cuts, bulges, low pressure, uneven wear, and any sign of bead or sidewall distress. Check the valve stems, confirm the spare is usable, and make sure the wheel hardware is secure. On a heavy pre-war luxury car, tire condition is only one part of readiness, so brakes, steering, cooling, and fuel-system reliability should also be part of the pre-drive routine.

Longer drives put sustained heat into older collector-car tires, which can reveal weaknesses that are less obvious during short local use. A few minutes of inspection before departure is far easier than dealing with a roadside problem in a large 1928 automobile. If the car has not been driven recently, taking a short shakedown run before the main trip is a smart way to spot pressure loss, vibration, or pulling while still close to home.