Convertible

1959 Cadillac Eldorado Biarritz

1967 Alvis TF 21 drophead coupé

A convertible or cabriolet (/ˌkæbrioʊˈleɪ/) is a passenger car that can be driven with or without a roof in place. The methods of retracting and storing the roof vary between models. A convertible allows an open-air driving experience, with the ability to provide a roof when required. Potential drawbacks of convertibles are reduced structural rigidity (requiring significant engineering and modification to counteract the effects of removing a car's roof)^[1] and cargo space.^[2]

Convertible roofs are made of folding material. Other types of demountable roofs include retractable hardtops (often constructed from metal or plastic) and detachable hardtops (where a metal or plastic roof is manually removed and often stored in the trunk).

Terminology[edit]

Other terms for convertibles include cabriolet, cabrio, drop top, open two-seater, open top, soft top, spider, and spyder. Consistency is rare about the current use of cabriolet in preference to convertible.^[3] The term cabriolet originated from "a light, two-wheeled, one-horse carriage with a folding top, capable of seating two persons", however the term is also used to describe other convertibles these days.^[4]

In the United Kingdom open cars with wind-up windows on their two doors and full weather protection were drophead coupés. Four-door open cars with wind-up windows and full weather protection were all-weather tourers.^[5]

History[edit]

1897 Daimler Grafton Phaeton

1929 Ford Model A cabriolet

Most of the early automobiles were open-air vehicles without any roof or sides.^[6][7][8][9] As car engines became more powerful by the end of the 19th century, folding textile or leather roofs (as had been used on victoria or landau carriages) began to appear on cars.^[10][11] Examples of early cars with roofs include the phaeton (a two-seat car with a temporary roof), the brougham or a coupé de ville (having an enclosed passenger compartment at the rear, while the driver sat in front either in the open) or the landaulet (where the driver has a fixed roof and the passenger compartment has a folding roof). Less expensive cars, such as the runabouts, sporting roadsters or sturdy touring cars, remained either completely open air or were fitted with a rudimentary folding top and detachable side curtains.

In the 1920s, when steel bodies began to be mass-produced, closed cars became available to the average buyer and fully open cars began their disappearance from the mainstream market.^[12] By the mid 1930s, the remaining small number of convertibles sold were high priced luxury models.^[11]

In 1939, Plymouth introduced the first mechanically operated convertible roof.^[13]

Demand for convertibles increased as a result of American soldiers in France and the United Kingdom during World War 2 experiencing the small roadster cars which were not available in the United States at the time.^[12] These roadsters included the MG Midget and Triumph Roadster. United States automakers manufactured a broad range of models during the 1950s and 1960s – from economical compact-sized models such as the Rambler American^[14] and the Studebaker Lark, to the more expensive models such as the Packard Caribbean, Oldsmobile 98, and Imperial by Chrysler.

During the 1970s, popularity of convertibles was severely reduced by the increased travel speeds on roads (resulting in more wind and noise for occupants) and proposed vehicle crash safety standards in the United States.^[12][15] Automobile air conditioning systems and sunroofs were also becoming popular, reducing the demand for convertibles.

In 1989, Mazda released the first generation Mazda MX-5 (called "Miata" in North America), which has become the best selling convertible with over 1 million cars sold.^[16]

Also in 1989, Toyota released the Toyota Soarer Aerocabin, which uses an electrically operated retractable hardtop roof.^[17] Only 500 were produced,^[18] however the retractable hardtop design has become increasingly popular in the 21st century.

Currently, models dedicated to the convertible body style include the Mazda MX-5, Porsche Boxster, Audi TT and Opel Cascada. Many other models also include a convertible body style in the model range.

Roof types[edit]

Textile[edit]

1967 AMC Ambassador convertible with its fabric top folded

A "soft top" is made form a flexible textile material. Common materials for soft tops are:

• Early convertibles used cotton canvas woven so tightly it is waterproof. However, automakers had problems in securing raw materials to fulfill orders after World War II, including canvas in various shades for convertible tops and limiting their manufacture.^[19]
• A cloth-based material has become more common in recent years.^[20]

Other materials are also used in the convertible top. By 1955, the most popular materials were latex and butyl rubber fabrics that each accounted for around 35% of the convertible top weight, with others included vinyl (12%), jute (8%), and rayon and acrylic fibers (Orlon), amounting to about 1% each in the compositions.^[21] Polyvinyl chloride (PVC) material was used for many convertible tops. The material consists of two layers: a top layer made of PVC, which has a specific structure depending on the vehicle model, and a lower layer made of fabric (usually cotton).

The collapsible textile roof section over an articulated folding frame may include linings such as a sound-deadening layer and/or an interior cosmetic lining, to hide the frame.

The folded convertible top is called the stack.

Detachable hardtop[edit]

A 1959 Daimler SP250 with detachable hardtop

Rigid removable hardtops, many of which store in a car's trunk, have been around at least since the 1950s.^[22][23] These normally provide superior weatherproofing, soundproofing, and durability compared to fabric-based tops, some with integrated rear-window defrosters and windscreens.

Examples include the Ford Thunderbird (1st-generation and 11th-generation), Mercedes SL (2nd-generation and 3rd-generation), Porsche Boxster, Jeep Wrangler, and Mazda MX-5.

Detachable hardtop with "porthole" side windows on a 1957 Ford Thunderbird

During the 1950s and 1960s, detachable hardtops were offered for various convertible sports cars and roadsters, including the 1955–1957 Ford Thunderbird and Chevrolet Corvette, as well as the 1963–1971 Mercedes-Benz W113 series of two-seaters. Because the convertible top mechanism is itself expensive, the hardtop was customarily offered as an additional, extra-cost option. On early Thunderbirds (and Corvettes through 1967), buyers could choose between a detachable hardtop and a folding canvas top at no additional cost, but paid extra for both.

The metal-framed "Carson top" was a popular addition for the 1930s Ford convertibles or roadsters because it turned these models into an almost instant hardtop.^[24] The design mimicked a convertible top, but lacking the bulky folding mechanisms enabled the removable hardtop to have a much lower and more rakish profile.^[25]

Improvements in canvas tops have rendered the detachable hardtop less common in recent years, in part because the top cannot be stored in the vehicle when not in use, requiring a garage or other storage facility. Some open cars continue to offer it as an option. For example, Mazda MX-5s has an accessory hardtop, which is compulsory for some auto racing series.

Retractable hardtop[edit]

A Volvo C70 with retractable hardtop

A retractable hardtop — also known as "coupé convertible" or "coupé cabriolet" — is a car with an automatically operated, self-storing hardtop (as opposed to the textile-based roof used by traditional convertibles).

The benefits of improved climate control and security are traded off against increased mechanical complexity, cost, weight and often reduced luggage capacity.

Other design features[edit]

MG TD open two-seater with tonneau cover over passenger seat and luggage space

Tonneau cover[edit]

Folding textile convertible tops often fail to completely hide their internal mechanism or can expose their vulnerable underside to sun exposure and fading. A tonneau cover provides a solution.

Rear window[edit]

Rear windows are often part of the roof assembly. Traditionally, the rear window in a soft-top was made from plastic, however more recently some convertibles have used glass for the rear window.^[26]

Windblocker[edit]

A windblocker or wind deflector minimizes noise and rushing air reaching the occupants.^[27] According to the engineer responsible for the 2008 Chrysler Sebring, its windblocker reduces wind noise by approximately 11 to 12 dB.^[28]

Several convertibles are available with a heating duct to the neck area of the seat, which is often called an "Air Scarf". Examples of cars with an Air Scarf are the Mercedes-Benz SLK-Class, Mercedes-Benz SL-Class and Audi A5/S5.

Safety[edit]

Modern safety features specifically for convertibles include:

• rollover protection structures (ROPS) with pyrotechnically charged roll hoops hidden behind the rear seats that deploy under rollover conditions
• heated rear window (for improved visibility)
• boron steel-reinforced A-pillars
• safety cage construction – a horseshoe-like structure around the passenger compartment 
• door-mounted side-impact airbag which inflates upward (instead of downward like the typical curtain airbag) to provide head protection even with an open window^[29]

Variations[edit]

Convertibles have offered numerous iterations that fall between the first mechanically simple but attention-demanding fabric tops to highly complex modern retractable hardtops:

Roadster: A roadster (also called spider or spyder) is an open two-seat car with emphasis on sporting appearance or character. Initially an American term for a two-seat car with no weather protection, usage has spread internationally and has evolved to include two-seat convertibles.

Cabrio coach: A cabrio coach (also called semi-convertible) has a retractable textile roof, similar to a traditional convertible. The difference is that a convertible often has the B-pillar, C-pillar and other bodywork removed, however the cabrio-coach retains all bodywork to the top of the door frames and just replaces the roof skin with a retractable fabric panel.

An advantage of a cabrio coach is that retaining more of the car's original structure means that structural rigidity is higher (or the vehicle weight is lower) than traditional cabriolets.^[30] An example of the cabrio coach is the 2003-10 C3 Pluriel,^[30] which has a roof with five possible configurations.^[31][32]

Fixed-profile: In contrast to convertibles where the entire bodywork above the beltline (doors, roof, side pillars, side bodywork) is replaced with a folding or retractable roof, the fixed profile convertible retain portions of fixed bodywork including the doors, side pillars, and side elements of the roof — while a center fabric portion slides back and accordions at the rear. As an example, Citroën's 1948 Citroën 2CV featured rigid bodysides and two doors on each side, along with a sunroof that rolled back on itself and extended to the rear bumper in place of a separate boot/trunk lid. Other fixed-profile convertibles include the 1950 Nash Rambler Landau Convertible Coupe, the Nissan Figaro (1991), the Jaguar XJ-SC (1983) and the 1957 Fiat 500 and its 2007 Fiat 500 successor. The 1984 Heuliez-designed Citroen Visa Decapotable used elements of a fixed-profile convertible.

Four-door: Most convertibles have two doors, however several four-door convertibles have been produced. Examples include the 1934 Buick Series 60 "Convertible Phaeton",^[33] 1938-39 Buick Roadmaster, 1940–41 Buick Super, 1941-1947 Oldsmobile 98 1941-47, 1939 Cadillac Series 61, 1940-41 Cadillac Series 62 and 1961-67 Lincoln Continental.^[34] Current production four-door convertibles include the Jeep Wrangler Unlimited.^[35][36]

Peugeot presented a concept four-door retractable hardtop convertible, the Peugeot 407 Macarena in 2006.^[37] Produced by French coachbuilding specialist Heuliez, the Macarena's top can be folded in 60 seconds,^[37] with a steel reinforcing beam behind the front seats incorporating LCD screens for the rear passengers into the crossmember.^[37]

Off-road: Several off-road vehicles have been produced with removable soft tops.^[38] Examples include the Jeep Wrangler, Suzuki Vitara, Suzuki Jimny,^[39] Ford Bronco, Land Rover Defender, Mercedes-Benz G-Class^[40] and early models of the Toyota Land Cruiser and Land Rover Defender. Typically, the soft tops attach to the roll cage or to the installation points on the vehicle's body.

Landaulet: A landaulet (also known as landaulette) is where the rear passengers are covered by a convertible top.^[41][42][43] Often the driver is separated from the rear passengers with a partition,^[42] as per a limousine.

In the second half of the 20th century, landaulets were used by public figures (such as heads of state) in formal processions. They are now rarely used, for fear of terrorist attack.

Gallery[edit]

Open car and roadster[edit]

Convertibles[edit]

Retractable hardtop[edit]

See also[edit]

Wikimedia Commons has media related to convertibles.

References[edit]

Further reading[edit]