Magazine for the professional tire industry
Issue link: https://mtd.epubxp.com/i/148910
Tall, thin tires The BMW i3 Concept Coupe has tires size 155/60R20 up front and 175/55R20 in the rear. OEMs as they explore technologies to improve safety and to meet the new 2016 and beyond CAFE and CO2 emission regulations." "If I had to guess — and this is based on what we hear from our OE customers — I don't see it in the next fve or six years for sure," says Pirelli's Carpino. "It's both technical and cosmetic at this point, more for the appearance of the vehicle." Carpino says Pirelli has heard from at least one of its OEM customers that for style, a popular look is to see the wheel well fully flled by its tire. Tat, at least today, requires a tire that is similar dimensionally to tires that are currently common. "For a while, it will just be more in the concept and electric and hybrid vehicles." Even if they did become more popular, manufacturing them would not require a major change in the existing infrastructure. Tire engineers told us that in The Pirelli Cinturato addition to new molds, manufacturing P1 Special Edition plants would only require some equipconcept tire was designed for Audi. It ment adjustments to produce the tires has 21-inch rims. en masse. What are the drawbacks? Tere are disadvantages to using taller, thinner tires on cars. "Te main disadvantage for the tall and narrow concept is the building space in the car, where ofen the wheel house must be changed," says Strübel. "Tat is more likely to happen in cases of the new architecture of electric and hybrid vehicles, where the car planning is starting from the beginning." Tere are no issues with traction when they are used on electric cars and hybrids, says Bridgestone's Hara. "Highperformance cars like today's Corvete are not in the scope of applications." 32 Hara says he does not anticipate any wear issues with tall, thin tires, either. "One of the challenges, but not necessarily disadvantages, of tall and narrow tires is that the overall diameter of the tire is larger," says Michelin's Knowles. "Vehicle weight and packaging are key factors that determine the tire dimension needed on a vehicle." Knowles says that in order to maintain the tire load capacity required for current vehicles, the overall diameter of a narrow tire must be slightly larger, thus the term "tall and narrow." "To take full advantage of the performance beneft of tall and narrow tires, vehicle manufacturers must adapt their designs to accommodate the larger diameter tires," he explains. Continental's Strübel says the outer diameter of the tire is an important consideration in the beginning of the concept phase of a new car and must, therefore, be discussed early in the vehicle's development. A longer lead time is necessary for this new size concept. "For electric vehicles, the rolling resistance of a tire is even more important than for combustion engines due to the limitation of the batery capacity," says Strübel. He adds, however, that a European OEM "is developing a vehicle with a combustion engine with such a tire size for market entrance soon." "We anticipate that these tires will be equipped on a widevariety of environmentally friendly vehicles," says Bridgestone's Hara. "Tese tires are ideal for EVs (electric vehicles) and HEVs (hybrid electric vehicles), as the lower rolling resistance is a signifcant beneft. However, we do not feel that their use should be limited to these EVs or HEVs." "Tat's going to be more for the OE to drive the market," says Pirelli's Navarro. "If a premium OEM partner comes to us and says we'd like your support in doing this, we believe in it and as a company that prides itself on innovation and research, we're going to go through with it. "Until you get the OE to agree to bolt that up as part of their strategy for their cars, I don't think it's anything we can impose on them." ■ MTD August 2013