The Deceptively Tricky Art of Designing a Steering Wheel

Cars didn’t always have steering wheels. The very first car—the 1885 Benz Patent-Motorwagen, invented by Karl Benz—used a tiller system: a horizontal bar with a handle mounted to a vertical bar. The lever-like handle was similar in many respects to a boat’s rudder. Amazingly, it would be another nine years before French engineer Alfred Vacheron saw sense and fitted the first known steering wheel to his 4-horsepower Panhard for the Paris-Rouen race. Just four years later, in 1898, Panhard made the infinitely preferable and safer steering wheel standard on all its cars. And we’ve been using them ever since.

Hans-Peter Wunderlich is Mercedes’ creative director of interior design. He has been designing steering wheels for 35 years. “I started in 1991 on my first,” he tells me. “A steering wheel is really the most challenging and difficult element to sculpture, to design, to develop in the car.” It is so difficult that Wunderlich has used the wheel as a test on potential recruits.

“When we hire a designer, I have given them the task, after I see a nice portfolio, to draw me a steering wheel,” he says. “The steering wheel is, for me, the proof. Should I hire them or not? If a designer is able to create a perfect steering wheel, even just as a scribble, then they will be a good designer for the total interior of a car.”

CAD design renders of Mercedes and Maybach designs before prototyping.

Courtesy of Mercedes

It was this challenge, in part, that attracted Ive and his team. “Our starting point was trying to understand the essential nature of the problem to be solved, and that normally means dismissing received wisdom,” Ive tells me. “A car is the aggregation of multiple products, and, in many ways, we’re designing furniture. We’re designing complex and sophisticated input methods. One of the challenges was to try to create cohesion. You don’t get something to be cohesive by a set of rules. That was a wonderful new challenge, and one wrestled with over a number of years.”

For both Ive and Wunderlich, science accompanies the art of design. They talk of the intricacies of the ergonomics, the logic of the switches, factoring in an “exploding element in the center” (the airbag), which is getting more and more complicated, says Wunderlich. “Even the rim is an ergonomic science in itself,” he adds, saying that his team works hand in glove with Mercedes’ in-house ergonomics department on these stages. “It’s almost 50-50. We get requirements data from engineering and ergonomics.”

Spinning Out

Look closely at your steering wheel rim; in cross-section, it won’t be round. Cut it into segments, and each will likely have a different profile, aiming to optimize grip wherever your hands grasp the wheel. Even the padding has to be just right. “It mustn’t be like bone but also not too fat. You need a nice balance,” Wunderlich says. “[It must say] this car is solid, it’s quality, it’s strong, it’s powerful, but it’s not crude.”

“If you hold the wheel on the three and nine o’clock positions, you can carve in with your fingers on the rear of the rim—so you have the hump, the scallop of the rim,” Wunderlich says. “And then we carve into a valley where your fingers could rest. That means your hands can close. You have the feeling you’re holding the car. This is so challenging, because in that area you have such a technical structure to maintain—complex electronics and heating elements. We torture the engineers to keep that area so small so we can sculpt it out.”

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