Sustainable Steering: Lexus' New Bamboo Steering Wheel

The human hand is an extraordinary tool. It can transmit as much brute force as the body can generate, carry out miraculously intricate feats of dexterity and precision, communicate just about every human emotion—and cool your face on a hot day. Hands control the direction and destiny of a car. In the new Lexus GS 450h, the vital connection between human and machine is kept pure by a bamboo steering wheel, fine-tuned by engineers and traditional artisans to be functional and beautiful to both hand and eye. The wheel's very particular shape was developed by Lexus "Meister" Shuichi Ozaki, as GS Chief Engineer Yoshihiko Kanamori explains. "After attaching pressure-sensitive material to his hands in order to measure stress points on the wheel, Ozaki could see which points of the wheel were being held most strongly, and sand down those sections.

Now, wherever you grip it, there's no stress for your hands.”
"When you're comfortable at the wheel, you don't feel tired even after a long drive," agrees the Lexus Meister. "I designed this wheel to give the driver a sense of security."
After a long and exhaustive development, Ozaki eventually pronounced himself satisfied with the shape. With typical Lexus thoroughness, he then revisited every other steering wheel parameter in search of further improvements. That resulted in a repositioning of the wheel towards the rear of the vehicle, an adjustment of telescopic range by 11 percent, and a two percent change in its angle.
"That last one might seem pretty minor," he says, "but you wouldn't believe the difference it makes." Even the stitching has been recessed so that it doesn't interfere with grip comfort.

But it's the bold, world-first use of bamboo that really grabs the attention. In fact, the choice is a perfectly logical combination of science and sensibility. Bamboo is dense and stable. It's also highly sustainable: some varieties can grow by 100 centimeters a day. Lexus-grade bamboo takes between three and four years to mature, still more than 10 times quicker than the 40 to 50 years taken by conventional woods.
Manufacturing the wheel is a challenging and very human-intensive process. Automotive wood specialists Miroku Techno Wood are based in Nankoku, in the Kochi prefecture of southern Japan.

They hand-pick bamboo trees for longitudinal splitting on a radial-blade cutter. These split sections are whittled down to form thin fillets.
After stress-processing and drying to achieve the exact moisture content, a stack of fillets is placed on a jig, laminated together using a high-frequency adhesion machine, and bent into a half-lifebelt shape. Four of these rough half-circle laminates are wrapped around either side of the top and bottom sections of the steering wheel "skeleton," where they're hand-planed, worked, and sanded into smooth tubular forms.
Final polishing to achieve Ozaki's ideal cross-sectional shape is done by hand. It's a highly skilled operation, tackled only by craftspeople with the right level of experience. The final gloss stage delivers a gentle texture, perfect driver feel, and a well-deserved "thank you" for your hands.

 

Courtesy Lexus-Global.com magazine