Forget about conventional sunroofs. Full-glass sliding roofs to give that light and airy feel and retractable hardtops that fold down in seconds are reaching 'must have' status.  Matthew Beecham reports on how the roof system market is shaping-up.

Roof systems are fast becoming part of a car's identity.  For example, the most eye-catching design feature on the Citroen C3 Pluriel is the multi-function roof system, which allows the car to be a cabriolet, spider, saloon and pickup.

Citroen is not alone in roof innovations. Panoramic sunroofs stretching the length and breadth of a vehicle are becoming increasingly popular on both sides of the Atlantic.  In the US, an increasing number of cars with panoramic glass roofs are being offered, notably the Pontiac G6 GT with its four-panel glass sunroof (the same model Oprah Winfrey gave to 276 members of her audience in a media stunt in September 2004.) The popularity of large and expensive sunroof systems on US vehicles is soaring.  They are available as options on everything from a Mini to a Cadillac SRX. This burgeoning new market offers suppliers a great opportunity to develop model-differentiating and value-added products, which translate into higher profits for them and OEMs.

Inalfa Roof Systems' consumer research confirms demand for light and airy cabins.  Eddy van der Vorst, Business Development Director for Inalfa Roof Systems, said: "A clinic conducted in cooperation with a customer and a research institute told us that the main benefits consumers see in their sunroofs are sky view and a brighter compartment. Consumers are starting to realize that air-conditioning is for cooling and a sunroof is for light and fresh air."  He also points out some challenges of panoramic sunroofs in terms of design and manufacture.  "A glass roof becoming larger and larger has a rising impact on the body structure. This impact plays an increasing role in sunroof design. Another aspect is the rising weight. Ways to reduce weight of the roof module is thus the other challenge."

One of the main reasons for this growth in the roof systems market is due to the popularity of sport utility vehicles (SUVs). As drivers traded in their passenger cars for SUVs, they brought along their demand for sunroofs. "I think the general observation is that bigger equals better," said Jeff Steiner, Executive Vice President and Chief Marketing Officer for American Specialty Cars Inc.  "The challenge is weight: you are putting more weight on the roof, which for SUVs and high centre of gravity vehicles is not a good thing.  The second thing in a lot of cases is the overall sun loading of a car.  If you have a huge glass panelled roof, that presents a problem from a heat-loading standpoint.  We are also seeing more combinations of fixed glass and moving glass roofs because it is a feature that you need to experience.  Once you experience a vehicle with a lot of glass or an open-air vehicle and you can manage some of the heat loads, you find that that is a very desirable feature that a consumer wants for their next vehicle." Formerly known as the American Sunroof Company, American Specialty Cars has kept its initials but re-invented itself over the past two years as a specialist body engineering company for low volume production vehicles.

All roof manufacturers predict massive growth in large sunroofs worldwide.  Brett Healy, vice president of Business Development planning for Webasto Roof Systems explained how the company is aiming to grow in the North American sunroof market.   He said:  "The first step is to sell more of what you have.  That is working for us.  At an industry level, approximately 25% of new vehicles come equipped with sunroofs.  We are above that in the projects we sell actually closer to 30%. We see that increasing by about 2% per year.  Our mission is 50/50 2010.  That means 50% fitment rate with a 50% market share for sunroof systems in North America by 2010.  Will we hit that? I'm not sure but it is tracking very positive. The second step is that our customers are starting to look at roof systems in three categories.  The first category is a traditional sunroof in which our customers are beginning to respond to our recommendations to commonise, i.e.  use the same sunroof on many vehicles.  That way we can give them better prices because of leverage.  Quality goes up, too.  We are now seeing that consistently across multiple customers.  Secondly, we see the growth of panorama roofs in North America. And then there is a new niche which falls in between a traditional sunroof and a full panorama roof system.  We call it a bottom load big roof.  It typically has moving glass in the forward passenger area and fixed or moving glass in the rear passenger area.  It is a unit which installs from underneath which is more traditional to a normal sunroof.  We believe this will be the fastest area for growth.  Over the next two car cycles, we see the majority of applications being traditional sunroofs, although the share of these bottom load big roof and panoramic systems is increasing very fast."

The quality of soft-top designs have also improved significantly over the last decade.  Better quality materials have brought benefits in acoustics and cabin temperatures, enabling us to drive rag tops comfort all year round.  They can even be driven through a car wash without any problems.  "The technical soft-top trend is similar to the retractable hardtop but more sensitive to apply," said Rolf-Peter Baule, head of Karmann's roof systems business. "The soft-top is more complex because of elastic behaviour of the textile components in combination with a high complex kinematics. This development needs a full competent supplier, which Karmann is. The latest evolution of materials for the exterior and headliner improved the noise level significantly as well as the surface feel. The individuality request of the changing market is also part of the development focus. Different colour and material combinations could be applied in combination with illuminated headliner/integrated light systems or spoiler systems in order to improve down force. The application of an exterior fabric in leather has been shown at the Geneva motor show this year, for instance."

The trend toward more convertibles and open-top vehicles has also created more opportunities for suppliers.  "We expect global demand for convertible will double over the next ten years," said Dr Christian P Eick, Marketing & Public Affairs Manager for Wilhelm Karmann GmbH.  "There are a number of reasons for that.  First, we see the retractable hardtop as additional demand.  In other words, we do not see a trade-off between soft-tops and retractable hardtops. Second, we are seeing convertibles becoming a 'must' in OEM's product line-up. There are still a number of brands that do not yet have convertibles in their product line.  We expect to see that change over the next decade.  By 2007, we expect to have more retractable hard tops than soft-tops in the world because the introduction of retractable hard tops in the compact segment. On the other hand, we expect to see a solid proportion of certain luxury models with soft-tops. VW has just disclosed that Karmann will develop partly the body and deliver the roof system for the Bentley Convertible.  This is also a soft-top.  Overall, however, we predict that the market for soft-tops will remain stable while the proportion of retractable hard tops will reach more than 50% by 2015, up from 35% today."

The French specialist in body-in-white and niche vehicles Heuliez also believes that the retractable hard top market is set to blossom. "When the Mercedes SLK appeared on the market seven years ago, the consensus was that the retractable hardtops technology would soon replace the conventional soft-tops and will be exclusively dedicated to exclusive car segments," said Bernard Girard, Director of Heuliez Deutschland and Business Development. "But opinions have changed.  Most people would now agree that retractable hardtops can be largely integrated in almost all car segments and that it will not only be considered as the replacement of the soft-top"

Heuliez believes that innovation and creativity in the field of retractable hardtops should not focus on complexity but much more in simplicity, manufacturability and reliability. Girard added:  "We have demonstrated this with the Opel Tigra TwinTop, developed and produced at Heuliez. The innovations of this car are not in the roof kinematics but in the packaging of the roof into the car and in its modular plug and play assembly concept.  We believe that there is great potential for integrating very simple roof systems into very innovative packaging.  This will be the best way to develop the market."

Expert Analysis

Global market review of automotive roof systems - forecasts to 2011 3rd edition

In this third edition report, we extend the analysis to provide market volume and value forecasts by product segment for conventional-size sunroofs in Western Europe, North America and Japan, from 2000 through 2011. We also take a closer look at the size of the convertible market in Europe and North America, the reasons for growth including an exclusive interview with ASC.

To find out more about this report, download your sample or to order your copy, please follow this link.