- May 7, 2012
Techsplanations: Tire Tread Technology
Pirelli and the development of grip and performance on wheels
Pirelli has distinguished itself in the tire market by creating products for its performance and racecars with technology that can then be applied to luxury and general consumer cars. The brand's renewed foray into Formula 1 racing after a 20-year absence has enhanced the emphasis on its tire technology, which hinges on tire tread designs.
In its second straight year of being the sole supplier for Formula 1 with the 63rd FIA World Championship at the Yas Marina circuit in Abu Dhabi, the tires feature squarer profiles, increased grip, and softer, more competitive compounds with consistent degradation.
Pirelli gleans real-time data from tires based on performance, temperature and pressure to optimize engineering and patterns. Tire tread pattern technology is an intricate art that can make all the difference.
What is it?
Tread patterns, quite simply, are the grooves and contours on a tire that give the wheel its grip and traction while allowing for performance capabilities. "Lugs" are the elevated parts of the tire that make contact with the road, and "voids" describe the space between the lugs that sluice the water through to avoid slippage.
Tread patterns can appear in symmetric, asymmetric, and directional tread patterns. Symmetric treads, the pattern most common on wheels (and found in Pirelli's Scorpion ATR tires), have continuous ribs or tread blocks where inboard and outboard sides match. Asymmetric tread patterns, effective in both dry and slick driving, vary the groove pattern along the surface of the tire such that as it turns, the tire can deflect water and grip snow while increasing contact area on dry roads; a balance of two worlds; this pattern is especially common for all-season tires. Directional tires have lateral grooves that form a V-shape across a tire's center as in Pirelli Winter Carving tires. The V-shape formation, much like a snow-plow skiing method, reduces the hydroplaning potential. Typically, tires with deeper grooves are better able to handle wetter conditions.
Indeed, the geometry of the tread blocks have very dedicated and specific functions depending on the size and application of the tire. Their size and sequence contribute not only to the noise and aquaplaning patterns but are also designed to optimize treadwear depending on their intended use-such as off-road applications for (Sc ATR) and high severity handling with P Zero.
How does it work?
Treads maintain grip while focusing on decreasing rolling resistance, the physical force that taxes a vehicle to produce more energy. In fact, the friction between the tire and road surface has a direct influence on fuel consumption, so the optimal tire tread pattern maintains safety and performance for a given road condition while limiting the resistance.
Achieving optimal rolling resistance requires a 360° in-depth analysis of the tire's dynamic performance and materials used. Specifically regarding the tread pattern (as an integral function of the tire profile and groove depth), the targets are to have a very uniform contact pressure distribution and reduced movement within the tire's footprint during use. Any flexing movement results in friction loss and thus absorbs energy. The orientation of the blocks within the footprint is a design tool to help achieve the reduced rolling resistance.
The Pirelli Cinturato offers environmentally friendly performance with innovative compounds, structure, and tread patterns conducive to lower consumptions and carbon dioxide emissions, more durability, and improved safety in all conditions. By cutting rolling resistance, a tire can roll more efficiently without requiring excess power. More angular profiles and softer compounds work to increase performance. The evolution of the Pirelli tires has originated from regulation changes introduced by the FIA regarding blown exhausts. This new measure, which should result in a reduction of aerodynamic downforce acting on each tire, requires a wider and more even contact patch. As such, the tires have a less rounded shoulder on each tire and using softer compounds, which produce better grip and more extreme performance. Tires set to be used in 2012 have a squarer profile in order to improve the wear rate, by preserving the tire shoulder by distributing stresses more evenly and lowering the risk of blistering. Though these tires have technology helpful for winning F1 races, the technology is easily applied to the most powerful sports cars currently on sale, such as Ferrari, Lamborghini, Porsche, Aston Martin and Bentley.
How is the racing technology applied?
Rally activity has always been an outdoor laboratory for off-road and M+S tires-in particular, winter tires-whether studded or not. Circuit racing and more recently the Pirelli F1 development has provided some interesting and useful materials which in part are transmitted directly to ultra high performance tyres such as the P Zero is a perfect example.
Also, another spin off from F1 is from the sophistication of the predictive modeling a simulation technology used, that become routine tools to greatly accelerate UHP tire technology and the application toward street tire development.
Why would I want it?
You'll get more mileage. The tread compound on Pirelli tires has been reinforced with specialized proprietary compounds to extend durability without compromising on grip. Turning on wet surfaces is safer with the right type of tire treads and can shorten the braking distance necessary when coming to a sudden stop. Scorpion Verde, for example, is a high-performance tire from Pirelli that is geared toward eco-conscious capabilities for SUVs and crossovers. Because it is made without highly aromatic oils, it reduces fuel consumption by up to 3.9% in city driving.
Is there a downside?
The initial expense of a high-quality tire could be an initial deterrent to purchase, but factor in the longevity of the tire, and you may be saving in the long run. That's not even factoring in the invaluable of safety and comfort brought about by treads conducive to traction and performance and the potential to save on gas mileage.
What vehicles offer it?
All vehicles offer different types of tire tread technology depending on the type of driving for which they are designed.
Bottom Line: Tire tread technology has an important influence over not only on performance and safety, but also fuel-efficiency carbon footprint reduction.