General Comments on Aerodynamics at Mercedes Benz

Aerodynamics at Mercedes-Benz: the added value

• Diverse advantages in everyday driving: increased range, more comfort and safety
• Long tradition: aerodynamic bests and modern measuring equipment
• Detailed aerodynamic optimisation: the new CLA with EQ Technology

Low air resistance means high efficiency. This makes aerodynamic behaviour crucial, especially for electric vehicles. Reducing the drag coefficient by just 0.01 increases long-distance range by about 2.5 percent. Based on an annual mileage of 15,000 kilometres, corresponding aerodynamic optimisation results in an extra 375 kilometres of distance.

Mercedes-Benz recognised early on that aerodynamics are key to efficiency. Accordingly, the list of models with top aerodynamic performance is long: It initially ranges from the W 125 of 1937^[1] to the 540 K “Streamliner” of 1938 and the C111² from the 1970s to the W124 of 1984, which with a C_d of 0.29 was the first production car to fall below 0.30. More recently, the CLA of 2013 with a C_d of 0.22, the EQS with 0.20, and the current CLA with EQ Technology with a class-leading 0.21 should be mentioned. Another aero champion is the VISION EQXX from 2022. With a C_d value of 0.17, this technology platform offers the wind even less air resistance than an American football. While the focus of the VISION EQXX was on efficiency itself, the AMG GT XX was primarily about ensuring that efficiency at speeds of over 300 km/h. Thanks not least to its C_d value of 0.19 and intelligent aerodynamics, the AMG secured 25 long-distance world records on the Nardò test track in August 2025.  

Previously, and especially in racing, achievable speeds and high cornering speeds, i.e., downforce, were the focus. Today, the main focus is on energy consumption and range while maintaining Mercedes’ famous and much-loved driving characteristics. But not only in terms of air resistance, but also in the other aerodynamic disciplines of aeroacoustics, keeping the vehicle clean, and open-top driving comfort, Mercedes‑Benz models have been at the forefront for many decades. Further information on the aerodynamic sub-areas can be found here.

This is also due to the high level of development effort that the brand with the star puts into this area: The “Large Wind Tunnel” in Untertürkheim was the world's first of its kind for automobile development. The first documented measurement took place there over 80 years ago on February 5, 1943. The “Large Wind Tunnel” is still in use. In 2013, Mercedes‑Benz once again took the lead in aerodynamic testing with the aeroacoustic wind tunnel at the Sindelfingen Development Centre. Further information on the measuring equipment can be found here.

Small details, big impact: aerodynamic optimization of the CLA

As great as the added value is in everyday driving, the aerodynamic optimizations of the vehicles are just as extensive, as shown below using the current example of the all-new electric CLA. With a C_d value from 0.21, this all-electric model is one of the best in its class. Within the series, the spread is also very small. This is partly due to the wide range of aerodynamically optimised wheels. These include, for the first time, a bicolour full cover for light-alloy wheels. Compared to a conventional wheel, it performs up to 15 C_d points better; compared to an already optimised aluminium aero rim, the advantage is still up to two C_dpoints. In addition, the aerodynamicists have optimised the wheel spoilers in front of the front and rear axles in detail across all inch sizes, thus minimising the influence of the wheels and tyres on air resistance.

In the area around the radiator grille and headlights, the joints were optimally placed and partially sealed. The underbody concept of the EQS and EQE has been further developed. The very smooth underbody is almost completely closed and the spring control arms and tie rods are also covered. The rear wheel cover is fixed to the body shell, so it has no joints to the surrounding components and therefore does not move with the axle when it compresses, for example. In order to avoid any aerodynamic compromises, Mercedes‑Benz even installs two diffuser variants on the rear of the all-electric CLA: for models without and with a trailer hitch.

^[1] On January 28, 1938, the Mercedes-Benz W 125 record car set a speed world record on public roads with its drag coefficient (Cd value) of 0.17: Rudolf Caracciola reached a speed of 432.7 km/h on the A5 between Darmstadt and Frankfurt.

[2] The record-breaking C111-III had a drag coefficient of 0.183.