1929 Cunningham Tire Fitment Guide

1929 Cunningham fitment centers on two sizes used on the Cunningham 8: 32X6.75 and 700-20. Both are bias-ply sizes and both mount on 20-inch rims, so the rim diameter is shared even though the size notation differs. The listed 700-20 products show approved rim widths ranging from 3.75 to 5.50 inches depending on the specific tire, which is why wheel width matters as much as the nominal tire size.

A Cunningham owner should treat those two sizes as separate fitment paths, not as interchangeable labels without verification. The smartest first step is to confirm what is on the car now, inspect the wheel itself, and compare the wheel width to the tire you are considering. That approach protects the car's stance, preserves restoration accuracy, and avoids choosing a tire that mounts on the right diameter but the wrong width range.

On a 1929 Cunningham, 32X6.75 is an antique diameter-by-section size. The first number, 32, refers to the tire's overall diameter in inches, while 6.75 refers to its nominal section width. That is different from later numeric sizing because the code emphasizes the tire's outside height rather than listing only section width and rim diameter in the modern way.

A buyer looking at 32X6.75 should think in terms of early tire language and period appearance. It is the sort of size marking associated with pre-war fitments where visual proportion and correct era notation matter to the finished restoration. Before choosing it, compare the wheel and any surviving size references on the car so you know you are following the size convention that belongs on your particular Cunningham 8.

On a 1929 Cunningham, 700-20 is a numeric bias-ply size. The 7.00 represents the nominal section width in inches, and the 20 identifies the wheel diameter in inches. Unlike the 32X6.75 format, it does not state overall diameter in the size code, but it still refers to a traditional bias-ply tire used on a 20-inch rim.

That matters because 700-20 is the size with currently listed product choices, including blackwall, wide whitewall, and double-whitewall versions from BFGoodrich and Firestone. It gives Cunningham 8 owners a clearer path when they want to match a specific visual style while staying within a pre-war bias-ply fitment. Wheel width still needs to be checked against the exact tire, since different 700-20 products are approved for different rim-width ranges.

Both sizes used on 1929 Cunningham are bias-ply and both fit 20-inch rims, so this is not a bias-versus-radial decision. The real choice is whether your Cunningham 8 should follow the antique 32X6.75 sizing convention or the numeric 700-20 sizing convention. Since the currently listed product selection is in 700-20, that size gives you visible sidewall choices and several product specifications to compare.

For a restoration-minded owner, the best answer usually comes from the car's existing wheel setup, surviving tire references, and the appearance you are trying to recreate. If you already know the car calls for 700-20, you can then sort between blackwall, whitewall, and double-whitewall versions. If the car points toward 32X6.75, verify that path carefully before moving away from it simply because the alternate size has more readily listed choices.

1929 Cunningham tire choices in 700-20 include blackwall, wide whitewall, and double-whitewall styles. BFGoodrich offers blackwall and wide whitewall versions in that size, while Firestone offers wide whitewall and double-whitewall versions. All of them remain within the period-correct bias-ply category, so the sidewall treatment changes the visual presentation more than the basic construction type.

That gives a Cunningham 8 owner some flexibility depending on the restoration target. A blackwall generally suits a more restrained, utility-minded pre-war appearance, while whitewall treatments emphasize the formal luxury presence that many late-1920s prestige cars wore so well. If the car is being prepared for judged events, use the sidewall style that aligns with the era, body style, and market presentation expected by the club or judging standard you follow.

BFGoodrich and Firestone both appear in the available 700-20 tire selection for 1929 Cunningham. BFGoodrich offerings include blackwall and wide whitewall versions, while Firestone offerings include wide whitewall and double-whitewall versions. All currently listed options are bias-ply tires intended for the same 20-inch rim diameter, but their approved wheel-width ranges and load-and-pressure pairings are not identical.

Brand choice on a pre-war Cunningham often comes down to the look you want and how closely a given tire lines up with your wheel width and restoration plan. Some owners prioritize a certain whitewall treatment, while others focus on the rim-width range that best suits the car's wheels. Once the size is settled, compare the exact tire's sidewall style, approved rim width, and rated load-and-pressure figure instead of choosing by brand name alone.

For 1929 Cunningham, the listed 700-20 tires all use a 20-inch rim diameter, but approved rim width depends on the specific product. Firestone 700-20 tires are approved for 3.75 to 4.00-inch rims, while the BFGoodrich 700-20 tires shown are approved for 5.00 to 5.50-inch rims. That is a meaningful spread, even though the sidewall size marking is the same.

A Cunningham owner should measure the wheel or verify it through a marque specialist before selecting a 700-20 tire. Choosing by size code alone can miss a wheel-width mismatch that affects the tire's profile and fit on the rim. Once the actual wheel width is known, it becomes much easier to narrow the correct product rather than simply the correct nominal size.

The two listed 1929 Cunningham sizes, 32X6.75 and 700-20, both use a 20-inch rim diameter, so they share basic wheel-diameter compatibility. That means the original Cunningham 8 wheels are within the right diameter family for both fitment paths. Diameter alone, however, is only one part of the equation because the exact wheel width still needs to suit the individual tire selected.

That is especially important if you are considering a 700-20 tire, since approved rim widths differ substantially among the available products. A wheel that accepts one 700-20 may not be ideal for another version carrying the same size marking. Before mounting anything, confirm the wheel width and compare it to the tire's approved range so the finished setup is mechanically sound and visually appropriate.

A 1929 Cunningham should be stored in a cool, dry space away from direct sunlight, electric motors, furnaces, welders, and other ozone-producing equipment that can accelerate sidewall aging. Bias-ply tires also tend to develop temporary flat-spotting more readily during long static storage than later radial designs. Keeping the car clean, the tires properly inflated, and the storage area stable in temperature helps protect both the rubber and the car's overall presentation.

For longer storage periods, move the Cunningham periodically or support it in a way that reduces constant load on one contact patch. Many collector owners also roll the car a short distance from time to time so the carcass does not sit in the same position for months. Those small habits help preserve ride quality and sidewall condition on a heavy pre-war luxury car.

On a 1929 Cunningham, tire life is usually judged more by age and condition than by mileage because collector cars often cover limited annual miles. A sensible rule is to begin close inspection once tires reach the five-to-seven-year range and to give serious replacement consideration as they approach ten years, even if the tread still looks strong. The tire's date code and overall condition matter more than how often the car is driven.

That matters because a low-mile pre-war car can still be riding on rubber that has hardened, cracked, or weakened with time. A tire that looks acceptable at a glance may no longer be the right choice for touring or event use. Checking age, sidewall flexibility, and any signs of cracking gives a far better picture than tread depth alone on a seldom-driven Cunningham 8.

Tires on a 1929 Cunningham should be inspected before every drive, and again more thoroughly before longer outings or tours. Look closely for sidewall cracking, tread separation, cuts, bulges, uneven wear, and any pressure loss that suggests an air-retention issue. On a large pre-war car, the tire carries a substantial share of the vehicle's roadworthiness, so small warning signs deserve attention early.

A longer pre-drive check should also include the spare and the condition of the valve stems. If your setup uses tube-type construction, the valve hardware and any slow air loss deserve special scrutiny because a touring car is only as useful as the condition of all five tires. Building that inspection habit is one of the simplest ways to make a 1929 Cunningham safer and more dependable on the road.

A 1929 Cunningham 8 would have been fitted in the bias-ply era, so bias-ply construction is the historically appropriate starting point. The two sizes associated with the model are 32X6.75 and 700-20, both on 20-inch rims, which places the car squarely in traditional late-1920s luxury-car fitment practice. No original-equipment brand should be assumed unless the car carries surviving records or other marque-specific evidence.

That means the right restoration choice begins with confirming which of those two period sizes belongs on your specific Cunningham 8. Surviving paperwork, factory literature, old photographs, and marque-club guidance are the best ways to sort out market or body-specific preferences. Once the size is settled, you can focus on the sidewall appearance that best reflects the way the car would have presented when new.

Correct tire fitment matters on a 1929 Cunningham because judges and knowledgeable enthusiasts notice size convention, construction type, and sidewall style on a formal pre-war luxury car. A bias-ply tire aligns with the era, while an obviously incorrect construction or an out-of-period sidewall presentation can change the car's stance and authenticity. Even when a tire physically fits the wheel, it may still look wrong for serious show work.

Owners preparing a Cunningham 8 for judged events should confirm more than just the 20-inch rim diameter. The exact size path, blackwall versus whitewall treatment, and the overall profile all influence whether the car reads as authentically restored. Event-specific standards can vary, so marque clubs and judging manuals are the right place to verify what a particular concours or club show expects.

On the 1929 Cunningham, BFGoodrich and Firestone 700-20 tires differ in sidewall offerings, approved rim widths, weight, and rated load-and-pressure figures. Firestone's listed versions fit 3.75 to 4.00-inch rims and include wide whitewall and double-whitewall styles, with a 1930-pound maximum load at 40 psi. BFGoodrich's listed versions fit 5.00 to 5.50-inch rims and include blackwall and wide whitewall styles, with ratings ranging from 1700 pounds at 36 psi to 1980 pounds at 42 psi.

Those differences matter because two tires sharing the same 700-20 size code may suit very different wheels and restoration goals. A Cunningham owner with narrower wheels will naturally look differently than one with wider rims, and sidewall appearance may steer the final choice just as much as wheel fit. Comparing the actual wheel width first makes the BFGoodrich-versus-Firestone decision much more straightforward.

1929 Cunningham tires can be suitable for highway use when they are in sound condition, correctly mounted, properly inflated, and matched to the wheel they are designed for. The currently listed 700-20 products do not show modern speed-letter markings, which is common for pre-war style bias-ply tires. On a car of this age, the vehicle's own braking, steering, suspension, and general mechanical condition often matter just as much as the tire itself at normal road speeds.

A prudent Cunningham owner should treat highway use as part of an overall vehicle-readiness question rather than a tire-only question. Fresh inspection, correct pressure, secure valve hardware, and confidence in the car's chassis systems all come first. If the car will be driven regularly at sustained road speeds, keep expectations aligned with 1929 engineering and drive within the limits of both the tires and the automobile.

Inflation pressure on a 1929 Cunningham should follow the size and product actually fitted, not a one-pressure-fits-all rule. The listed 700-20 products show rated load-and-pressure figures of 1930 pounds at 40 psi for the Firestone versions, 1980 pounds at 42 psi for one BFGoodrich version, and 1700 pounds at 36 psi for another BFGoodrich version. Those figures are tire ratings, not automatic vehicle settings.

Use the Cunningham's original literature or trusted marque guidance to establish the vehicle target pressure, then make sure the tire chosen is suitable for that use within its published rating. Do not transfer a pressure figure from one 700-20 product to another just because the sidewall size looks the same. Matching the pressure plan to the actual tire on the car is the safer and more accurate approach.

Before a longer drive in a 1929 Cunningham, inspect each tire for cracking, cuts, bulges, loose or damaged valve stems, uneven wear, and any sign of tread or casing distress. Confirm cold inflation pressure, look over the spare, and make sure the wheel-and-tire combination on the car is the same setup you intend to tour on. A heavy pre-war automobile asks a great deal from its tires, so tire condition deserves a careful look every time.

That tire inspection should be part of a broader road-readiness routine that also includes brakes, steering, cooling, and basic fluid checks. On a car from 1929, the safest long drive is the one prepared conservatively rather than optimistically. Catching a weak sidewall, an aging spare, or a pressure issue in the garage is far easier than dealing with it on the shoulder of the road.