Pirelli used both P6 and P7 brand names back in the 1970s and 1980s, so the new tires are, in effect, a revival of past products. The latest models, though, are a lot different from the old ones due to technological progress on various fronts. Basically, the P7 is a higher performance version of the P6, thanks to differences in tread design and compound. Imagine, for example, that you'd use a P6 on a basic Volkswagen Golf hatchback and a P7 on a high-performance Golf GTI model. Both tires have deep, longitudinal grooves for better performance in wet weather.
Few motorists realize that the only reason tires have treads is to displace water.
If we drove all the time on dry surfaces, we could happily use something like racing slicks with no tread at all. I tried several cars, including models from Mercedes-Benz, Volvo and BMW, on a race track drenched with water from a spraying system and was amazed at how well the new tires handled the slippery conditions. Obviously, those four deep grooves were doing their job. I also pushed the tires to their limits on a dry track using various Alfa Romeo, BMW and VW automobiles and although they screamed in protest pretty well all around the tight circuit, they were tough to break loose. Another challenge tiremakers face is coming up with an efficient tread design that gets the water displacement job done effectively, yet doesn't generate a lot of road noise.