Change your tires! Michelin Airless tires, Bridgestone quieter tires

June 6, 2019 by Steve Hanley

---

The electric vehicle revolution has revolutionized our idea of ​​what a car should be, but the tires on which it rolls have remained essentially the same pneumatic items used for decades. Some tire manufacturers have tried to reduce the rolling resistance of their tires to increase the range of electric cars, but they are still prone to punctures and damage due to road hazards, such as potholes.

Back from the tweel!

At the beginning of the 21st century, Michelin unveiled the Tweel, which combines the wheel and tire in one piece and does not depend on atmospheric pressure to function properly. According to Wikipedia, "the potential benefits of the Tweel include not only the obvious safety and convenience of never having flat tires, but also, in automotive applications, the Tweel airless tire has the potential to be better able to brake – a compromise important performance that is inherent to tires.

"Unlike tires, a Tweel can be designed to have high lateral stiffness while having low vertical stiffness. This can be achieved because, in the Tweel design elements, the vertical and lateral stiffnesses are not inextricably linked and can therefore be optimized independently. As there is no air bladder under the tread, the carvings can, if you wish, incorporate even a water evacuation through holes of the design, this which eliminates or significantly reduces hydroplaning.

"Michelin expects the tread to last two to three times longer than a conventional tire. Since the rubber tread around the outer circumference is replaceable when worn (as opposed to scrapping a worn out tire), the potential impact of a tire Tweel-free air on the environment may be less than that of a conventional tire. "

This last part is significant. Having a replaceable and more durable tread means a lot less waste. The qualities that make conventional tires so durable also make them almost indestructible. Hundreds of billions of them are thrown into dumps around the world, where they are conducive to infectious diseases and pose a threat to surrounding neighborhoods as they catch fire.

Michelin has had some success with the Tweel for low-speed commercial applications such as forklifts, lawn mowers and other electrical equipment, but it has failed to break the passenger car market. Until now. He developed a new version called Uptis, which refers to the unique puncture-resistant tire system, which combines rubber and composites to create a mesh structure between an aluminum hub and the tread.

According to Michelin, the Uptis rolls as comfortably as a normal tire, but has several important benefits that could make it ideal for electric cars and autonomous cars of tomorrow. As it does not depend on the atmospheric pressure, it is not necessary to worry about punctures or road damage, which means that it is not necessary to equip cars with pressure monitors. air, spare tires and jacks.

Weight gain is an essential criterion for EV manufacturers. The structure of the Uptis can be modified to meet the specific needs of each manufacturer: more lateral stiffness for sporty models, more comfort for city driving or reduced rolling resistance for maximum reach.

according to AutoblogGeneral Motors has announced that it will begin testing a fleet of Chevrolet Uptis-equipped vehicles in southern Michigan this year, with a view to making them available as an option on production cars by 2024. Engadget points out that the main advantage of Uptis technology could be autonomous robotics where downtime due to punctures is eliminated. To learn more about Uptis, check out this video from Michelin.

Bridgestone's quieter tires

Electric cars are so much quieter than their gasoline and diesel cousins ​​that drivers hear things they never did before, like the sound of wind and the sound of tires on the road. According to Dale Harrigle, chief engineer of Bridgestone's replacement tire division, it appeared that the air was trapped and compressed by the tread along the sidewalk. When this air is released, it creates many small resonance noises that are in the same frequency range as normal human speech. "It makes communication in vehicles difficult," he says. Wired.

When developing his new Turanza QuietTrack tire, Harrigle told Bridgestone's engineers to circle it with a few thin longitudinal channels and numerous diagonal grooves leading to the tire's shoulder. The orientation of these lateral grooves is crucial. Those located along the shoulder allow the air to escape when it rolls, so that it is not compressed. And the grooves exist in three different widths, measured so as to interfere with the sound pattern of the other. This pattern of interference reduces noise in frequencies similar to human speech.

Finally, Harrigle and his team discovered that by molding a few millimeter serrations in the trough of each channel, they could break the high-frequency sounds generated when the tire interacted with the road. In addition, these serrations improve traction during snow.

QuietTrack tires cost about $ 133 per piece, a fairly normal price for a modern passenger car tire. If you are driving an electric car and want to reduce the noise inside the cab of your car, consider using these new Bridgestone tires when fitting new sneakers. If only CleanTechnica readers are doing it and want to share their opinions on the difference between their new Bridgestone and their old tires, we would be happy to hear from you.

Keywords: autonomous car, Bridgestone QuietTrack tire, electric car, General Motors, Michelin Uptis, road noise, Tweel