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All-Round Talent

Text
Sabrina Kolb

Photos
Ulrike Myrzik

Hi-Tech on Wheels

For many drivers, large, sporty-looking wheels are an absolute must. But these are more than just desirable design objects; they are also packed with innovative technology. Here are five distinctive examples from the Audi lineup.

1
Hybrid Wheel – Audi A5

The 5-spoke Y-design alloy wheel is a distinctive visual signature on many Audi models. For the latest generation of the Audi A5, this has now been taken to the next technological level as a hybrid wheel. The rim section of the two-piece wheel is made using an extrusion process. The solid base material is first pressed into shape. This creates a tube that is then rolled into its final form. The next step is to pre-cast the aluminum spoke section that is visible to the outside. This is subsequently shaped using a combination of pressing and forging. The rim and spoke sections are then laid on top of one another and bonded together under pressure and temperature using a process known as friction stir welding (FSW). This production process saves more than three kilograms. The wheel’s enormous weight benefit, however, has absolutely no negative impact on the design. The technology at play is hidden. Different designs and colors can be applied to the same wheel section. Offered exclusively by Audi, the Hybrid Wheel is available initially in galvano grey metallic. With a slight variation, the “double-bow” design also features on the Audi A7.

2
Active Aero Wheel – Audi R8 e-tron

The Active Aero Wheel on the Audi R8 e-tron is a major piece of road-going innovation – its moving polymer composite elements adapt the aerodynamics of the wheel to the road speed. At a standstill and at speeds of up to 60 km/h, these additional elements between the spokes are open, thus allowing improved airflow to the brakes. They close at higher speeds, reducing drag and lowering fuel consumption. The wheel is based on a classic five-spoke rim – the epitome of sporty design for many car fans. The shape is first rough forged then milled into its final form. This is followed by four further process steps: After a coat of black paintwork, the areas between the spokes are machined and treated with a protective layer. The spokes are then turned to a high gloss finish, with no need for subsequent grinding or polishing. The subsequent layer of lacquer fully protects this fine surface finish. The polymer composite elements give the Active Aero Wheel of the R8 e-tron the look of a turbine. Each of the blades closes flush with the outer surface of the wheel. Because the rear part of each blade opens inward and the front part outward, Audi now has, for the first time, left-hand and right-hand wheels.

3
Forged Wheel – Audi RS 4

The wheels of the RS cars accentuate the powerful dynamics of Audi’s sporty top models – powerful performance combined with subtle understatement and a high level of everyday usability. The flared wheel arches of many Audi RS models create room for large wheel diameters and wide tire formats. This makes the spokes deeper and the wheel looks more vibrant, dynamic and emotional. Depth and geometry also lend a sporty character to the otherwise elegant-looking ten-spoke design. The exclusive forged wheel offers optimized aerodynamics and a distinct weight advantage compared with conventional cast wheels. The blank is initially pre-formed, before the design is then forged and the rim well rolled and machined in a process of up to seven stages. A procedure known as stress relieving is carried out to eliminate the internal stresses that develop during cooling, and prevents the wheel from distorting during further processing. The final step is applying the paint coat. The wheel pictured here also serves as an example for further Audi models and is available as an option for the Audi A3, Audi A4 and Audi A5.

4
Cast Wheel – Audi A1

The cast aluminum wheel is an Audi Original accessory. In terms of its design, this allows for greater freedom in setting individual accents, the aim being an even sportier, more angular effect than on the standard wheel. This also allows the character of the car to be adapted precisely to customer desires – right through to the range of available colors. A high level of precision and stability are among the benefits of the well-proven aluminum casting technology. After being cast in its final form, the wheel is then machine polished and painted. The high-gloss segments are arranged in a manner that breaks the typical circle to create a new impression of a wheel through variations in angle and depth. Different colors underscore this effect. The wheel pictured here is tailor-made for the Audi A1, giving it a sassier, sportier look.

5
Aluminum Technology Wheel – Audi A8

The ten spokes of the new Aluminum Technology Wheel appear to cling directly to the tire. The outer ring of the rim is virtually indiscernible. The technology remains unobtrusive, yet the effect is bursting with energy – it screams movement and dynamism, even at a standstill. The new technology divides function and design. A forged ten-spoke aluminum wheel forms the base structure, topped by a cover made from injection-molded polymer. The two parts are permanently bonded using polyurethane foam, with cavities between the design and the skeleton filled with foam. This is highly beneficial to the safety and stability of the wheel. Minor incidents, such as scraping along a curbstone, present no technical issues as only the cover and not the structure is affected. The weight benefit is also enormous. The new wheel saves 4.4 kilograms over a comparable forged wheel in a conventional design – a technological milestone.

Andreas Valencia Pollex Audi Wheel Designer
Although all wheels are round, there is still plenty of room left for creativity. The constant stream of new cars will always be accompanied by new wheels. The symbiosis of design and the latest technology consistently pushes back the boundaries of feasibility. That’s the appeal of my job.

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Audi Design Wheels
Every Audi model has its own wheels. Only on rare occasions are particularly popular designs used on several models. For the designers, this means they have to develop around ten new wheels per model. The development time and testing takes up to two years per design before it enters series production and can be built onto the car. It is crucial to ensure that the design of the wheel suits the car. The proportions of the wheel have a major impact on the overall impression conveyed by the vehicle.