A convertible is an automobile body style that can convert between an open-air mode and an enclosed one, varying in degree and means by model. Convertibles evolved from the earlier phaeton, an open vehicle without glass side windows that may have had removable panels of fabric or other material for protection from the elements.
Historically, a retractable roof consisted of an articulated frame covered with a folding textile-based fabric similar to that on an open carriage evolved into the most common form. A lesser seen detachable hardtop provided a more weatherproof and secure alternative. As technology improved a retractable hardtop which removes and stows its own rigid roof in its trunk appeared, increasingly becoming the most popular form.
A semi-convertible also known as a cabrio coach has a retractable or removable top which retains fully framed windows on its doors and side glass. A landaulet is a semi-enclosed convertible with a fully enclosed front cabin and an open rear, typically with a folding fabric top and roll-down glass all round.
- 1 Other terms
- 2 Folding textile roof
- 3 Detachable hardtop
- 4 Retractable hardtop
- 5 Galleries
- 6 See also
- 7 References
- 8 External links
In British English: drophead coupé is used instead of "convertible". Other common terms include cabriolet, cabrio, soft top, drop top, rag top, spider, and spyder. Historically, a spider was an open two-seat car with no provision for a top, as with the Porsche 550 Spyder, and thus not a convertible. In time the term has been adopted to describe removable and retractable hardtops.
Folding textile roof
The collapsible textile roof section (of cloth or vinyl) over an articulated folding frame may include linings such as a sound-deadening layer or interior cosmetic headliner (to hide the frame) – or both – and may have electrical or electro-hydraulic mechanisms for raising the roof. The erected top secures to the windshield frame header with manual latches, semi-manual latches, or fully automatic latches. The folded convertible top is called the stack.
Pros and cons
Among the advantages of convertible tops are:
- All-round visibility
- Maximized ventilation
- Ease of entry and exit
- Ability to transport large objects
- Enhanced driving pleasure
Disadvantages of fabric top convertibles include:
- Potentially reduced safety.
- Poor break-in protection.
- Deterioration and shrinkage of the sun-exposed textile fabric over time.
- Problems with trunk floor pan rust-through due to leakage of an improperly maintained top.
- A heavier vehicle and higher curb weight due to additional structure required to restore both torsion and flexure stiffness normally provided by a metal roof and (in some cases) door window frames, and additional weight from motorized mechanisms (where provided). Body-on-frame styles usually included an entire X-brace within the conventional ladder frame.
- A narrower rear seat due to space required by the folded side rails.
- Potential diminished rear visibility due to smaller rear window or UV deterioration of plastic pane
- Potential diminished structural rigidity, requiring significant engineering and modification to counteract the effects of removing a car's roof.
- Potential scuttle shake, where an insufficiently rigid bulkhead between engine and passenger compartment can impact ride or handling.
- Potential reduced aerodynamics compared to an equivalent coupe, especially with the top down.
- Potential increased wind noise, moisture intrusion with the top up
- Potential reduced cargo space.
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 provide a solution.
Side windows non-existent in open cars which may have detachable side screens, are manually or power operated glass side windows as in a saloon or sedan. Rear-windows have evolved similarly, with plastic rear-windows appearing as late as the first generation Porsche Boxster. Contemporary convertibles and retractable hardtops feature heatable glass rear windows to maximize visibility – though rear windows often can compromise visibility by their size, as with the case of the very small rear window and restricted visibility of the Mitsubishi Eclipse Spyder. Plastic windows can degrade, fade, yellow and crack over time, diminishing visibility.
A windblocker or wind deflector minimizes noise and rushing air reaching the occupants. Mazda pioneered a version on the RX7 convertible which featured an integral rigid opaque panel that folded up from behind the front seats. Current convertibles feature windblockers of various designs including detachable fold-up designs (e.g., Toyota Solara), vertically retractable glass (e.g., Audi TT), minimal flaps (e.g., Mazda Miata) – or other integrated wind controlling systems.
Contemporary convertible design may include such features as electrically heated glass rear window (for improved visibility), seat belt pre-tensioners, boron steel reinforced A-pillars, front and side airbags, safety cage construction – a horseshoe like structure around the passenger compartment – and roll over protection structures or (ROPS) with pyrotechnically charged roll hoops hidden behind the rear seats that deploy under roll-over conditions whether the roof is retracted or not.
The Volvo C70 retractable hardtop includes a door-mounted side impact protection inflatable curtain which inflates upward from the interior belt-line – vs. downward like the typical curtain airbag. The curtain has an extra stiff construction with double rows of slats that are slightly offset from each other. This allows them to remain upright and offer effective head protection even an open window. The curtain also deflates slowly to provide protection should the car roll over.
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 was an open two-seater possibly with a frame that required actual assembly (i.e., not retracting) and separately installable soft side "window" panels – offering little protection from inclement weather and often requiring time-consuming apparently complicated installation. Examples range from the very first cars to the vintage Porsche Speedster introduced in 1955, and the Jaguar XK120 Roadster unveiled in 1948 right up to the most recent Porsche Spyders. For most in the U.S., a contemporary roadster is a two-seater convertible such as the Jaguar F-Type, BMW Z8, Aston Martin V8 Vantage, and Dodge Viper.
Landau & Rigid Door: Citroën's 1948 Citroën 2CV featured a sunroof that rolled back on itself, and extended to the rear bumper in place of a separate boot/trunk lid. This was for loading versatility that pre-dated hatchbacks. Later models had a boot/trunk lid or an optional hatchback, and an internally opening sunroof, with a secured 'half-open' position. It had rigid body sides framing two doors on each side – followed in concept by such cars as the 1950 Nash Rambler Convertible Coupe.
- a hatchback with a multi-layer insulated top.
- a full-length "landau" sedan, operable partially or to the back window or any stage in between, with a buffet-minimizing wind deflector over the windshield.
- a semi-convertible, with the roof open to the back window, the roof assembly folds into a well in the trunk floor.
- a full convertible, whereby roof side rails are unlatched and removed.
- a roadster pick-up, where the back seats fold to a pickup-like bed with a drop-down tailgate.
The Four-Door: Buick advertised a Series 60 "Convertible Phaeton" body style in the 1934 Model Year, which was actually a four-Door convertible,  1938-39 Roadmaster, and 1940-41 Super. Oldsmobile in the 98 Series 1941-47, and Cadillac in 1939 Series 61, and 1940-41 Series 62 models. The Lincoln Continental was available as a 4-door convertible in model years 1961 to 1967. The only current production 4-door convertible is the Jeep Wrangler Unlimited.
Peugeot presented the a concept four-door retractable hardtop convertible, the Peugeot 407 Macarena in 2006. Produced by French coachbuilding specialist Heuliez, the Macarena's top can be folded in 60 seconds, with a steel reinforcing beam behind the front seats incorporating LCD screens for the rear passengers into the crossmember.
Drophead Coupe, Coupé Cabriolet or Coupé Cabrio: A type of convertible with only two doors, and thereby recalling the cabriolet carriage. With its Mazda RX7 convertible, Mazda introduced a two-seater convertible with a removable rigid section over the passengers, removable independently of power operated textile section behind with heatable glass rear window. During the 1980s, Jaguar produced an XJ-SC with two removable panels over the front seats and a partial fold-down convertible section in the back. It retained the rear side windows of the coupe and had fixed cant rails above these and the door glass. This allowed an almost full convertible with roll-over safety. Going back in Jaguar history, during the 1950s the XK 120 Drophead Coupe (DHC) and later variants, provided open-air motoring with quite civilized fully lined insulated tops with the weather-protection of the hardtop models.
Until the 1910 introduction by Cadillac of the United States' first closed-body car, the open or convertible car was the primary body style. U.S. automakers manufactured a broad range of models during the 1950s and 1960s – from economical compact-sized models such as the Rambler American and the Studebaker Lark, to the more expensive models such as the Packard Caribbean, Oldsmobile 98, and Imperial by Chrysler.
Proposed major safety standards suggested during the mid-1970s for the 1980 model year included a 50-mile-per-hour (80 km/h) crash to the front, at 25 mph (40 km/h) on the sides, as well as a rollover at 30 miles per hour (48 km/h), a test that open top convertibles would unlikely be able to pass. Although the requirements were reduced, sales of convertible body styles were falling during the early-1970s. Automobile air conditioning systems were also becoming popular. In 1976, Cadillac marketed the Eldorado as "the last of the American Convertibles". During this period of low convertible production, T-tops became an alternative for a few models.
In the 1980s convertibles such as the Chrysler LeBaron and Saab 900 revived the body style in the United States – followed by models such as the Mazda Miata, Porsche Boxster, Audi TT, and later retractable hardtop models.
Rigid removable hardtops, many of which store in a car's trunk, have been around at least since the 1950s. These offer generally superior weatherproofing, soundproofing, and durability to fabric-based tops, some with integrated rear window defrosters and windscreens. Examples include the first and eleventh generation Ford Thunderbird, second and third generation Mercedes SL, Porsche Boxster, Jeep Wrangler, and Mazda MX-5. Many of the rigidity concerns of a standard convertible are present, even with the roof attached. However, weatherproofing, climate control, and cabin security are improved.
American Ben P. Ellerbeck created the first practical retractable hardtop prototype in 1922 — a manually operated system on a Hudson coupe that never went into production. The first French version was the Georges Paulin designed 1934 Peugeot 601 Éclipse
Advances in electronics, hydraulics, and weatherproofing materials have made the modern retractable hardtop increasingly popular. Pros and cons include ease, enclosed car quality climate control with the top up, improved crash resistance, and passenger compartment storage security on the plus side and increased mechanical complexity and expense and, more often than not, reduced luggage capacity on the minus.
A 2006 New York Times article suggested the retractable hardtop may herald the demise of the textile-roofed convertible, and a 2007 Wall Street Journal article suggested "more and more convertibles are eschewing soft cloth tops in favor of sophisticated folding metal roofs, making them practical in all climates, year-round."
Retractable hardtops can vary in material (steel, plastic or aluminum), can vary from two to five in the number of rigid sections and often rely on complex dual-hinged trunk (British: boot) lids that enable the trunk lid to both receive the retracting top from the front and also receive parcels or luggage from the rear – along with complex trunk divider mechanisms to prevent loading of luggage that would conflict with the operation of the hardtop.
Open car and roadster
Semi-convertible Nash Rambler Convertible "Landau" Coupe c. 1950
Jaguar XK c. 2008, with heatable glass rear window and fully automatic cloth top with integral top-concealing rigid tonneau
Mercedes SL c. 1963, perhaps the most popular detachable hardtop
Lincoln Continental c. 1966, 4-door with integral automatically operating, self-storing tonneau
Jaguar E-type c. 1970, with vinyl foldable tonneau installed and snap-secured
Cadillac Eldorado 1972, with detachable, two-part, fully rigid "parade boot" tonneau cover
Citroen 2CV c. 1975, with roll-back roof and rigid doors
Rolls Royce Corniche c. 1986, a high-end prestige marque with a manually installed tonneau cover
Volkswagen New Beetle c. 2003, with raised textile (cloth) convertible top featuring interior headliner, an acoustic insulation layer, and heatable glass rear window
A Fiat 500 (2007) semi-convertible
1966 Rolls-Royce Phantom V landaulet
Mercedes-Benz 300d landaulet in operation
- Garrett, Jerry (8 October 2006). "2007 Volkswagen Eos: In Praise of a Convertible Goddess". The New York Times. Retrieved 6 March 2011.To neutralize the loss of torsional rigidity inherent in any convertible, VW engineers cleverly took the basket-handle roll bar of the VW Cabrio, inverted it and placed it under the rear seat pedestal. A beefed-up windshield frame of hot-stamped ultra-high-strength steel is connected directly to the floorpan’s reinforced frame rails. Steel tubing provides more stiffness behind the doors for an extra layer of safety. Partly as a consequence, rear seat passengers have about 10 inches less shoulder room than in the smaller Rabbit.
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