How Automakers Had Almost Once Dropped the Drop-Top

2024 Ford Mustang Convertible at 2024 Canadian International AutoShow (Photo Credit: Chris Nagy/Car FYI Canada)

Sometimes in life it’s best to open up. For automobiles, an opportunity to reveal an inner personality is realized with convertibles. Despite the prevalence of air conditioning on almost every modern vehicle, convertibles remain special for delivering occupants the feeling of being one with the world with the rushing breeze when in motion and the warmth of a summer sun. This sensation continues to impress up to this day with cars such as the Mazda MX-5, Ford Mustang convertible, BMW 4 Series Cabriolet and the Mercedes-Benz SL Roadster, it may be disturbing to know how the excitement of open top motoring almost rendered extinct to North American audiences roughly 50 years ago. A perfect storm of circumstances contributed to a near death for the convertible.

The Top Goes Up For Safety

The first half century of the automobile was propelled by unbridled innovation and imagination. However, by the late 1960s, the time of unchecked freedom with automotive design and construction making its way to roadways was over. An alarming rise in fatal car accidents resulted in seat belts becoming mandatory safety equipment on all passenger cars. Although most governments on the globe pursued rules to make new vehicles safer, the United States and its superior auto market at the time had the power to greatly influence how and what kind of cars would be built.

A 1956 Mercury Montclair Convertible (Photo Credit: Chris Nagy/Car FYI Canada)

Proposed in 1969 and issued in 1971, US Federal Motor Vehicle Safety Standard 208 was created by the NHTSA (National Highway Traffic Safety Administration) as a comprehensive measure to reduce injuries and fatalities in vehicle crashes. The pursuit of safety improvements during the 1970s included an initiative to enforce seat belt use as well as improve occupant protection in event of a vehicle rollover. 

Despite the mandate for seat belts to be installed in new vehicles, safety harness usage amongst the motoring population was disturbingly high. The deployment of mandatory automatic seat belt on passenger cars was viewed as a means to overcome the behaviours of the time. When applied to production vehicles, automatic seat belts would appear in two designs. An initial method involved installing the seat belt mechanism on the door while the belt remains latched. Later, a motorized automatic seat belt would also appear on a handful of cars. Mindful that the incorporation of automatic seat belts would have proved difficult with convertibles, rollover standards had the potential of practically dooming the vehicle style. 

Throughout the 1970s, there was a push for the more stringent safety regulations with a strong opposition coming from auto companies. However, the efforts of  NHTSA had also begun to receive growing support from the driving public that demanded safer vehicles willing to sacrifice other attributes such including engine power and other fun-loving automotive features. 

The Other Reason The Convertible Almost Disappeared

The proposed safety regulations were threatening to make production of convertibles unpopular but the sad reality at the time was the customer base at the time was also deciding the fate of open top vehicles prior to any government intervention. When cars with fully enclosed interiors became commonplace by the 1920s, soft, retractable roofs started a transition to the vehicle type becoming a novelty. 

1929 Auburn 8-90 Boattail Speedster on display at 2015 Canadian International AutoShow (Photo Credit: Chris Nagy/Car FYI Canada) 

By the 1950s, convertibles routinely accounted for a small percentage of sales for major automakers. For example, more than 1.9 million examples of Chevrolet’s high-end Bel Air line were produced between 1955 and 1957 with a modest 130,122 examples attributed as convertibles. While a niche body style in the 1950s and early 1960s, convertibles were still attractive to car buyers and auto companies generally charged premium prices for the drop-top model in their product lines. From 1955 to 1959, stock car sanctioning body NASCAR operated the National Convertible division.

By the middle of the 1960s convertible sales took a much deeper dive. In the case of popular Ford Mustang, 73,112 convertibles were built in 1965 but demand dropped below 10,000 by 1970. Although overall Mustang production was lower (190,727 in 1970 compared to 569,451 in 1965), the Mustang convertible accounted for a smaller percentage of yearly sales. With only 9 percent of 1973 Ford Mustangs being retractable soft top examples, there would not be a convertible variant of the redesigned 1974 Mustang. Chevrolet’s pony car fighter, the Camaro, had already ditched the convertible offering in 1970.   

1973 Ford Mustang Mach 1 Convertible (Photo Credit: Chris Nagy/Car FYI Canada)

The first generation Chevrolet Corvette and Ford Thunderbird were famously only offered as convertible roadsters. When the Thunderbird took a new form in 1958, the debut of a hardtop proved overwhelmingly popular. While production issues for the 1958 T-Bird led to hardtop numbers unfairly skewing to 94 percent of the 37,892 vehicles sold for the year, a more plentiful supply of the car in 1959 resulted in 67,456 vehicles produced with just 10,261 examples being convertibles. Continuing lower demand for the convertible variant of the Ford Thunderbird led it the body style being dropped after 1966. The Ford Thunderbird would not after again in convertible form until the model’s brief revival in 2002.

Interesting with the Chevrolet Corvette, the convertible remained popular even with the first appearance of the hardtop Corvette Sting Ray in 1963. With exception to the 1963 model year, the convertible outsold the hardtop model of the second generation Chevrolet Corvette through its run up to 1967. Popularity for the convertible remained in the debut of the third generation Corvette representing 65.2 percent of the 28,566 sports car’s 1968 production run, this number dropped with the hardtop gaining dominance starting in 1969. By 1975, the percentage of soft top Corvettes totalled roughly 12 percent of the year’s production. Chevrolet discontinued the Corvette convertible in 1975. 

One of 14,436 examples of the 1967 Chevrolet Corvette Sting Ray Convertible (Chris Nagy/Car FYI Canada) 

The expectations of new safety regulations appeared to hasten the lost love for the convertible. In 1976, Cadillac made noise when the final examples of the Eldorado Convertible for that year were touted as what would be the last American-built convertible. Only a handful of foreign vehicles such as the Triumph TR6, the MG B as well as the Mercedes-Benz SL line remained for sale as traditional convertibles. While the proposed safety regulations would have affected cars sold in the United States, the potential of the new safety measures would influence the design and development of vehicles of international automakers. Eyeing a market too lucrative to be ignored, Triumph initially elected to not even develop a drop-top version of the TR7.

Drop-top Alternatives 

Even though the full convertible treatment was uncommon through the mid to late-1970s, automakers selling cars in the United States recognized there was still demand for open-air motoring. In addition to traditional sunroofs, several vehicles adopted innovative solutions for providing a convertible-like riding experience while remaining mindful of possible rollover standards. 

Made popular by Porsche, one convertible alternative solution was an assembly incorporating a removable roof section mainly situated over the front row passenger area. Known as a Targa top with Porsche, the design was adopted by other automakers during the 1970s and 1980s. Common in North America, the T-top roof design emerged featuring two removable panels above the driver and passenger. Discontinuing the convertible following the 1975 model year, the Chevrolet Corvette added a glass T-top roof option in 1978. The feature sold on just 972 examples of the sports car in 1978 but would be found on nearly 3/4s of Corvettes in 1981.

1979 Pontiac Firebird Trans Am equipped with T-top roof (Photo Credit: Chris Nagy/Car FYI Canada)

While passenger cars based on convertibles had disappeared, it was possible to buy a removable hard or soft top in truck form. Technical exceptions applied to trucks allowed convertible styling with the Jeep CJ, International Scout and Ford Bronco to remain in production in North America through the 1970s. 

Return of the Ragtop

As the 1970s progressed, safety wasn’t the only focus automakers and the car driving public. This time coincided with an aggressive push for cleaner emissions, the oil crisis as well as overall cost of living increases that proved crippling for auto sales. Economic conditions and aggressive lobbying by automotive sector entities resulted in limitations in the deployment of safety measures promoted through US Federal Motor Vehicle Safety Standard 208. The mandatory safety requirements for automatic seat belts were frequently delayed into the 1980s with the attempt to improve occupant protection in a collision showing a reasonable concept that was poorly executed in the real world. Partly due to unpopular and sometimes even dangerous appearance of automatic seat belts, the push for better frontal crash survivability saw standard airbags being favoured. 

In addition to automatic seat belts falling out of favour, the future of convertibles was aided by the rollover compliance option using a roof crush resistance test involving an angle load test placed on the front left corner of a vehicle near the top of the windshield.

Fiat 124 Sport Spider (Photo Credit: Chris Nagy/Car FYI Canada)

While the convertible body style option was spared, automakers were still hesitant for building one. Sunroofs and removable panel roofs continued to appear instead of full drop-tops. Entering the 1980s, selection of convertible cars in North America was sourced from foreign brands. American branded convertibles would eventually return less than a decade after the vehicle type almost went extinct. In 1982, Buick offered a drop-top version of the Riviera and Chrysler debuted the LeBaron convertible option based on the company’s new K-car platform. The Ford Mustang convertible returned in 1983 (Continuing to be offered to present day more than 30 years later). For 1984, Cadillac revived the Eldorado convertible with its announcement celebrated by many but also earning the ire of collectors who purchased the 1976 convertible believing it to be the final one that would be built by the luxury car brand. 

A major renaissance for the convertible occurred in later in the 1980s when Mazda generated a sensation with their modern MX-5 Miata roadster. Through the 1990s and early 2000s the Porsche Boxster, Mercedes-Benz SLK, BMW Z3 as well as the Honda S2000 showed open-air motoring in a super exciting manner.

First Generation Mazda MX-5 Miata (Photo Credit: Chris Nagy/Car FYI Canada) 

Convertibles remain a special niche in the automotive market in 2024 shining while the weather shines. However, the selection of the body style has been threatened by the auto industry’s recent favouring of crossover vehicles instead of proper cars. Although the Jeep Wrangler and the new Ford Bronco have worshipped convertible ideals, the Nissan Murano Cabriolet and Range Rover Evoque Convertible were not major successes. 

Perhaps future summers with drop-tops may return to glory as some auto companies appear to, at least, open to a new car-based designs. Concept cars including the Genesis X Convertible, Polestar 6 electric as well as newly-released Cadillac Sollei serves to bring hope for open-air driving moving forward.