Magazine for the professional tire industry
Issue link: https://mtd.epubxp.com/i/148910
Tall, thin tires going to be in that tire to generate heat and rolling resistance," says Steve Carpino, vice president, R&D;, North America for Pirelli Tire North America. What is a tall, thin tire? "A tall and narrow tire is very diferent in terms of global shape from current tires," says Jim Knowles, senior product category manager, Michelin North America Inc. "In general, they have a reduced tire width and an increased overall rim diameter compared to current tires." "It's a higher pressure, skinnier tire," says Pirelli's Carpino. Continental's tire engineers had to start with a new approach to the Conti.eContact while still ensuring that the tire excelled at wet braking. Wide circumferential grooves, optimized tread depth, a fat contour and smooth offshoulder design result in an effcient and durable tire for the electric vehicle market. "Even if it has the same diameter or is taller, there are just certain match-related efects that will generate less heat and rolling resistance." Carpino says that one of the challenges in designing tall, thin tires is maintaining load-carrying capacity. "Say you have a Ford Fusion that has a 225/55R17 tire today. If you try to replace that tire with a tall, skinny tire, it still has to be able to carry the same load as that conventional tire. You can get that load-carrying capacity by keeping the same air volume. Air is what carries the load in a pneumatic 'I think the trend toward lighter vehicle weight is growing. Te vehicles equipped with large and narrow tires are the next generation in this process.' Hank Hara, Bridgestone Americas tire. You need to have a certain volume of air to infate, to carry that same load. You can get that by going to a taller sidewall and a narrower tire." Carpino says that one of the biggest benefts of tall and thin is beter fuel economy if they are designed to ofer comparatively lower rolling resistance. Depending on the tread patern and compound, a skinny tire also will perform beter in aquaplaning conditions. Unlike in the days of the Ford Model T, tall, thin tires today are generally designed to replace a specifc shorter, wider tire. "Te size range for tall, thin tires depends on what your starting point is," says Carpino. "If 255/40R19 is where you're starting, then you go up to something like 235/55R17. It's going skinnier, but it's not going any taller." As far as speed ratings go, Carpino says the kinds of vehicles that would be riding on these tires generally are not the unlimited speed range vehicles. "I would expect they would still have to be in the H and V category at the higher end, and probably you could get away with S and T on some of the lower-level vehicles. On most vehicles today, if you're talking car tires, H and V are not uncommon at all. If you're doing this on conventional vehicles, you'd have to maintain that kind of performance." Te tall and thin driving force "Everyone's looking for (energy) efciency right now, and taller and skinnier is a way to be more efcient," says Rafael Navarro, vice president of communications, media relations and motorsports, Pirelli Tire North America. "You can infer that that is what spiked the curiosity. I don't know that it's a trend. I don't know if it's anything that's going to take the tire industry by storm." While it still remains uncertain whether or not tall and thin Europe, noise reduction and tall, thin tires Part of the movement toward tall, thin tires is being driven by the European Union, where regulations on exterior noise are in effect. The EU says that a tire's exterior noise grading is expressed in decibels, with one, two or three sound waves for the label. One black wave indicates the best noise level performance. It means that the noise output level of the tire is at least 3dB below the future legal limit. Two black waves indicate sound levels that are in the moderate range. Three black waves indicate the weakest performance in terms of tire noise output. It represents a noise output level between the current maximum and the new lower limit that will be introduced in Regulation 661, coming into force by 2016. 28 The European Union requires tires to display the European Commission's exterior noise grading. Two black waves means the noise output is moderate. Quik-Link: 800-687-1557 ext. 19111