Air-filled (pneumatic) tires give our vehicles comfortable, cushiony rides. (Thanks tires, we appreciate that.) Looking at it from another perspective, pneumatic tires are containers of pressurized gas that are being subjected to constant abuse, and when something happens to them, it can result in a situation that falls somewhere between a minor annoyance and a deadly catastrophe. We’ve ridden on these things for about 130 years now, and while they’ve improved substantially since John Dunlop invented them to keep his kid from getting headaches while riding his bike, it seems that we can still do better. Hankook is trying to make better happen with a consumer-oriented airless tire.
Instead of pressurized air as a shock absorber that can also support the weight of the vehicle, airless tires (also called non-pneumatic tires, or NPTs) use deformable solid materials (usually rubber) to achieve the same effects. Here’s a concept video from a couple of years back:
There are already airless tires in production: Michelin sells the Tweel for agricultural vehicles, and Polaris has been offering an ATV with NPTs since late 2013. What’s new is Hankook’s announcement that it has been aggressivley testing its NPT for applications that require more than low-speed ruggedness. Among them is the passenger vehicle. The series of “rigorous tests” that the company is putting its tires through are meant to prove their durability, hardness (efficiency), stability, ability to take high-speed turns (slalom), and ability to maintain their integrity at high speeds (up to 130 kilometers per hour). Hankook says that “the impressive results in all five categories demonstrated that the NPTs could match conventional tires in terms of performance.”
That’s all good stuff, but what’s especially promising is that Hankook has been able to vastly improve the efficiency of its manfacturing process, reducing the number of steps to four from eight. The NPTs are recyclable, too. None of this is any guarantee that Hankook will be releasing a consumer product any time soon; it’s going to take a lot of safety testing before this new type of tire is allowed on the road. But durability and performance testing and a focus on manufacturability likely means that these tires are (finally) treading beyond the prototype stage.
Evan Ackerman is a senior editor at IEEE Spectrum. Since 2007, he has written over 6,000 articles on robotics and technology. He has a degree in Martian geology and is excellent at playing bagpipes.