Sport-Touring Motorcycle Tires
In recent years, as sport-touring motorcycles have increased in both power and weight, Metzeler realized that a need existed for a specialist tire to cope with the ever-increasing demands. The result is several patented technologies for their new Interact version of the highly acclaimed Roadtec Z6. Metzeler certainly has the technical expertise to create a dual (actually, up to seven!) compound tire. However, its engineers felt that the "step effect"-the change in the tire’s behavior-as the tire transitions from one compound to the next, would be too exaggerated on a heavily laden sport-touring machine. The effect would be especially pronounced as the tire wears.
Metzeler uses a single steel cable drawn continuously around the outer circumference of the tire; it is the only manufacturer not to use several individually joined cables. By loosening the cable’s tension at the shoulders, flex is increased; the more the rubber can flex, the more heat (and, therefore, grip) it can generate. By varying the gap between each cable loop, and carefully tuning the tension, the Metzeler engineers were able to create a tire that is hard-wearing on the crown and, paradoxically, progressively softer and grippier toward the shoulders. Metzeler also developed a new high-silica rubber compound designed to work in extreme temperatures, wet or dry-very useful for the touring rider. The end result is a long-lasting, sticky tire that acts like a multi-compound, without any step effect. Further, because the way the carcass is wrapped, the tire’s characteristics and performance remain constant to the end of its life.Fitted to my personal Triumph Sprint ST, the new Roadtec Z6 Interact tires made the bike noticeably smoother and more stable in a straight line, and yet it turned quickly and precisely into corners. The Metzelers were predictable and had phenomenal grip-the engineers have clearly gotten it right. If they wear in the way Metzeler claims, the company will certainly have a winner on its hands.