E-Class Cabrio completes Merc drop-top range
BY BYRON MATHIOUDAKIS | 3rd Jul 2017
Following in the footsteps of the larger S-Class and smaller C-Class models, the four-seater E-Class Cabriolet is scheduled to be launched in Australia in September.
The new model is also the first full-sized four-seater ragtop since the demise of the old E-Class 20 years ago, replaced by the outgoing E-Class that was actually built on the more compact previous-generation C-Class platform.
The result of this change, according to Mercedes-Benz head of vehicle testing for E-Class Peter Kolb, clears up any confusion of what an E-Class Cabriolet should be while offering buyers of premium convertibles the widest choice available anywhere in the world.
“The previous E-Class Cabriolet was more a ‘C’ base … but our marketing philosophy is now to have a convertible in each of the classes,” he told GoAuto at the launch of the new model in Italy late last month.
“We wanted (to provide) a clearer picture of our philosophy (this time around).”Based on the Modular Rear-drive Architecture (MRA) that began development in 2009 and was unveiled with the current C-Class in late-2013, the newcomer has grown in length by 123mm, width by 74mm and wheelbase by 113mm, while the front and rear tracks have been pulled out by a considerable 67mm (to 1605mm) and 68mm (to 1609mm) respectively.
The result is a substantially more spacious cabin.
The initial discussions on where Mercedes-Benz was heading with its three-pronged four-seater convertible plans commenced in 2010. The S-Class was the first to market in 2015 (and the first ragtop to wear the flagship moniker since 1971), followed by the C-Class convertible last year and now the E-Class.
The emphasis was to position the middle convertible with more luxury than its C-Class sibling and more sportiness than the S-Class version, according to Mr Kolb.
“The C-Class and E-Class convertibles were developed side-by-side but stagnated with the smaller one to come out first, and the E-Class was to have more of a luxury focus,” he said.
Also prompting the E-Class’ growth to full-sized status is to fill the clear space between the medium four-seater convertibles such as the Audi A5 Cabriolet and the upper-echelon drop-tops like the Maserati GranCabrio and Bentley Continental GT. If nothing else, German car-makers love filling a niche.
“The new E-Class Cabriolet has a unique positioning in the market now,” Mr Kolb explained. “Rivals are either smaller like the BMW 4 Series Convertible or much more expensive.” As a consequence, models from Maserati, Bentley and others were seen as important goals for the A213 to strive towards, though ultimately none served as benchmarks, as the S-Class was considered to be best in the business for quality, refinement and technology. For rolling road noise, rear-seat acoustics and mechanical noise the new Cabrio is at the top of its game, according to Mr Kolb.
“We looked at all (of the luxury brands) for reference, but targets were internally driven,” he said.
Fitted with an array of different layer materials, the soft-top is designed to cope with temperatures ranging from minus 40 degrees Celsius to plus 80 degrees Celsius, while the roof is rated at around 20,000 operation cycles – four times more than a convertible averages in its entire lifetime.
Cold weather testing was conducted in Germany and Sweden while for hot weather assessment Spain and Arizona in the United States was chosen. While Mercedes states publicly that the roof can be raised or lowered on the move to 50km/h, it can actually operate at speeds up to 60km/h.
Although the sedan’s platform (including its advanced four-link front and five-link rear suspension system offering optional air suspension) served as the base of which the Cabriolet was sprung off, plenty of additional engineering upgrades were necessary for the drop-top to meet Daimler’s standards of best-possible acoustic comfort and driving dynamics.
To cut noise, vibration and harshness (NVH) properties, the front part of the floorpan was beefed up, while an innovative rear subframe is fitted around the rear seat area, allowing for the introduction of a split/fold rear backrest for the first time in an E-Class soft-top for added cargo convenience.
Additionally, a fresh rollover-protection system has been devised in the form of a pair of cartridges integrated in the space behind the backseat tops that aren’t visible unless deployed.
Besides doing away with the old rear-headrest-type offered elsewhere that compromised the style as well as seat comfort due to their upright nature, they are said to work more effectively in combination with the reinforced windscreen pillars during an inversion.
These plus a host of other measures mean body flexing resistance is also among the best of any four-seater convertible. Compared to the old E-Class, torsional stiffness rises 38 per cent. Interestingly, this bodes well for future performance variants.
“The E-Class Cabrio’s platform is certainly strong enough for AMG,” Mr Kolb hinted, which could materialise in the form of an AMG 53 version.
Achieving lightness to offset the extra bracing, too, was paramount, prompting a combination of weight-saving die-cast aluminium (including in the front mudguards, bonnet and bootlid) and sheet metal applications for the bodyshell.
All up, the E-Class Cabriolet is about 150kg heavier than the Coupe, but only around 50kg of that is as a result of structural stiffness enhancing the rest is due to the rear-subframe cradle, soft-top and its motors, rollover mechanism and other convertible-specific add-ons.
“Most of that extra weight is in the rear section,” Mr Kolb revealed. “As there is no more B-pillar and roof compared to the Coupe, the Cabriolet needs to be reinforced.”Finally, there was never any consideration of a folding hardtop like that of the BMW 4 Series, and not just because of the higher centre of gravity and styling compromises such a design necessitates.
“Our research shows that buyers want other people to see that this is specifically a soft-top,” Mr Kolb said.
