SEAT Leon SC

The C-segment defines the European market. The Volkswagen Golf still defines the C-segment, and the VW Group dominates the class too – it operates here with four different brands, more than any of its rivals. Although it could be a product planning nightmare trying to ensure that they compete with other manufacturers and not with each other, the strategy seems to work.

The SEAT Leon is one of the group’s C-cars. First launched in 1999, the five-door hatchback shared a platform with the Golf but was styled more like a coupe. It proved quite successful, especially the high-performance Cupra version, which many consumers thought had better handling than the equivalent Golf GTI.

The second-generation Leon appeared in 2005. Like its predecessor it was developed on a common underbody – VW’s PQ35 platform this time – and benefited from a multilink rear suspension in place of the earlier torsion-beam axle. And although still five-door only, the designers pushed the coupe theme a little harder, concealing the rear door handles in the D-pillars.

But by now, the VW Group had come to see that the constraints of platform engineering outweighed its benefits. Sure, there are economies of scale in many areas but sharing floorpans, for example, can compromise weight, packaging and styling when used across several brands and model lines that are all trying to do different things.

Wheelbase debated

Which is why the MQB modular vehicle architecture was developed. Key dimensions and much of the hardware is identical, but there’s more flexibility to change things which really helps to differentiate one model from another. It’s transformed the third-generation Leon, which is the first to offer a three-door body style, known as the SC. But as well as losing two doors, it also loses 35mm from the wheelbase – this would not have been feasible in the past.

“The first scenario was again to build a five-door that looked like a three-door, and we also thought about having a three-door version with the same wheelbase as the five-door,” said Fermin Soneira Santos, SEAT’s director of whole-vehicle engineering and chassis development. “But when we compared the design models we decided that the three-door must have the wow effect and therefore you need a shorter wheelbase. It was a design-driven decision, but weight reduction was also an important, positive effect of that.”

At the start of any programme the management team always produce a long list of the things they most want to improve, agree on the measures that will help them to get there, and then set technical targets for them. It’s a very complex process involving trade-offs that can be very hard to resolve.

On the SC, however, Soneira Santos says that deciding what should go at the top of the list was easy: “Weight – that’s the key thing. Developing a car is always about compromise. Usually, everything you improve has – somewhere – a negative component. There’s only one thing that doesn’t, and that’s weight reduction.” 

Losing two doors and shortening the wheelbase has inherent advantages here, obviously, but achieving the overall target still took a massive effort. The results are pretty impressive: at 1,168kg, the entry-level variant is more than 110kg lighter than its equivalent from the previous-generation Leon range. Tight margins mean that easy wins such as aluminium hoods were not feasible. Instead, savings came from optimising pretty much everything in the vehicle.