The deceptively difficult art of steering wheel design

Cars did not always have driving wheels. The first automobile—the 1885 Benz Patent-Motorwagen, invented by Karl Benz—used a tiller system: a horizontal bar with a handle mounted on a vertical bar. The lever-like handle was similar in many respects to a boat rudder. Amazingly, it was another nine years before French engineer Alfred Vacheron saw the logic and fitted the first known steering wheel for his 4-horsepower Panhard car for the Paris-Rouen race. Only four years later, in 1898, Panhard manufactured the preferred and infinitely safer steering wheel in all of its cars. We have been using it ever since.

Hans-Peter Wunderlich is Creative Director of Interior Design at Mercedes. He has been designing steering wheels for 35 years. “I started in 1991 for my first experience,” he told me. “The steering wheel is actually the most challenging and difficult element to sculpt, design and develop in the car.” It is so difficult that Wunderlich would use the wheel as a test for potential recruits.

“When we hire a designer, I give him the task, after I see a great collection, to draw me a steering wheel,” he says. “The steering wheel is the guide for me. Should I rent them or not? If a designer can create a perfect steering wheel, even if it’s just scribbles, he or she will be a good designer of the overall interior of the car.”

CAD rendering shows Mercedes and Maybach designs before prototypes.

Courtesy of Mercedes

It was this challenge, in part, that attracted Yves and his team. “Our starting point was trying to understand the fundamental nature of the problem to be solved, and that usually meant rejecting received wisdom,” Yves told me. “A car is an assembly of multiple products, and we are, in many ways, designing furniture. We’re designing complex, sophisticated input methods. One of the challenges was trying to create cohesion. You can’t have something that is cohesive by a set of rules. This was a fascinating new challenge, and one we’ve grappled with over a number of years.”

For both Eve and Wunderlich, science accompanies the art of design. They talk about the complexities of ergonomics, the logic of the switches, and taking into account a “blast element in the centre” (the airbag), which is getting more complicated, says Wunderlich. “Even the edge is an ergonomic science in itself,” he adds, saying his team is working alongside Mercedes’ internal ergonomics department at these stages. “It’s almost 50-50. We get requirements data from engineering and ergonomics.”

Rotate outward

Look closely at the rim of your steering wheel; In cross section, it will not be round. Cut it into segments, and each will likely have a different profile, with the goal of improving grip wherever your hands grip the wheel. Even the padding must be correct. “It shouldn’t be bone-like, but not too fat. You need a good balance,” says Wunderlich. “[It must say] This car is solid, quality, strong, powerful, but not primitive.

“If you hold the wheel at the three and nine o’clock positions, you can carve with your fingers on the back of the rim — so you have a hump, a scallop of the rim,” says Wunderlich. “Then we move to the valley where your fingers can rest. That means your hands can lock in. You have the feeling that you’re holding the car. And that’s very difficult, because in that area you have such a technical structure that has to be maintained – complex electronics and heating elements. We torture the engineers to keep that area very small so that we can sculpt it.”

You tortured Rafael de Simone, Ferrari’s chief engineer and chief development driver. De Simone is sometimes described at the company as “Customer No. 1” because, apparently, no Ferrari leaves the factory until he is satisfied with its performance.