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While not so popular on the new car market any more, folding hard tops offer bargain topless thrills, yet Rob Marshall finds that they can also cause severe headaches.
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Fashion is a fickle mistress; what goes around comes around. In motorcar terms, a new feature can be usurped by an improved version of the technology that it was supposed to replace. The folding metal roof, or the coupé/cabriolet, is a good example of this irony.
Perhaps because of our changeable weather, convertibles are very popular among UK motorists, with drivers desiring to soak up the rays, no matter how briefly. Leaving a removable hard top at home in our suddenly changeable weather is the main reason why folding canvas roofs became the default option for open-top motoring. Yet, questionable security, compromised bodyshell rigidity and increased interior noise remained notable downsides. The fabric also does not last forever and used car buyers tended to get jittery, if viewing a car with a tatty, or inoperative roof.
Enter the coupé/cabriolet
While folding metal roofs had appeared many decades before on niche cars, their popularity rocketed during the early 2000s. Improvements in technology, electro-hydraulics, electronic control units (ECUs) plus manufacturing and design meant that a roof could split into several sections and fold away into the boot at the press of a button. These roofs in operation put on an impressive show, although the technically-aware motorist will be aware of potentially big repair bills should any part of the complex mechanism fail.
While folding metal roofs address the fabric type’s disadvantages, their complexity, high cost and compromised luggage compartments put off many used buyers. Furthermore, the increased weight that contributes to higher fuel consumption and CO2 emissions put off car manufacturers as well, many of whom reverted to fabric roofs.
Simple in principle... complex in practice
According to Charlie Berry, proprietor of HoodTech in Chester, a renowned specialist in both fabric and metal folding roofs, coupé-cabriolets share operating principles with the more complex fabric roof designs. They work using electrohydraulics. A mineral fluid is contained within a reservoir, pressurised by an electric pump. The fluid is forced into a valve block, containing solenoid valves that open and close, diverting the fluid to where and when it is needed. The fluid travels through flexible plastic pipes to hydraulic rams that operate the mechanical mechanisms.
