Tire giant Metzeler may be able to help sport and sport-touring riders keep their pocket books in their pockets a little longer with the introduction of the company’s new sport-touring tire, the Roadtec Z6 Interact.
Like a number of tire makers, Metzeler has taken notice of the increase in performance of today’s sport and sport-touring machines. BMW, as an example, is claiming 175 hp and 103 ft-lbs from its new K1300S, with the K1300GT not far off that mark at a claimed 160 hp and 99 ft-lbs. Adding complexity to making a tire for such powerhouses is the fact that these types of motorcycles typically handle as well as they go fast. The Interact is Metzeler’s answer.
Interact is the next evolution of the successful Z6. In this latest iteration, Metzeler has bucked the current multi-compound trend in favor of using a single compound that “interacts” with a unique new tire carcass.
Metzeler’s patented 0-degree steel belt radial structure received a neat twist, literally, in the design of this latest tire. Briefly, the outer layer of steel “threads” in a tire’s structure – the portion of the tire beneath the rubber that contacts the road surface – is said to be a 0-degree belt construction when the steel threads run, or more correctly are wound, in the same direction as the tire's rotation. A primary benefit of such construction is said to be a high level of stability at high speeds. Metzeler’s patent in this process is that the winding is a single steel thread wrapped continuously to form the belt.
What makes the Interact’s steel belt different is the steel thread itself. The thread is more like a twisted cable, similar to a guitar string, rather than being a solid wire. With this construction the ability to control thread tension in specific areas of the tire is possible, therefore controlling temperatures of the tire compound in those areas.
They are approximately 120 steel threads that make up the steel belt. The number and spacing of threads allows for a progressive reduction of the winding from center to edge, with more thread in the high tension center and less thread in the lower tension/higher grip edge. Metzeler staff explained that this progressive winding method helps contribute to consistent feel and performance when transitioning into a lean or turn.
A do-it-all tire?
The perfect multi-tasking street tire would be one that retains high mileage without sacrificing grip or ride comfort. By placing more steel windings closer together in the tread center more tension is created meaning less flex in this area. Less flex means less friction, less friction means less heat, ideally meaning less wear. Conversely, in the shoulder area, more space between the steel windings means more give or flex, and as we just noted above, more friction means more heat. More heat means softer rubber which usually means better grip, in this case right where it’s needed.
Complementing this new carcass is a new, high silica content compound containing a 35-percent higher silica ratio than the previous Roadtec Z6. Claimed improvements here are better wet and dry grip, as well as consistent wear through the tire’s life.
The claimed end result of the technology in the new Interact is a single-compound tire that functions similar to a multi-compound tire while at the same time avoiding what Metzeler calls the “step effect.” The tire company defines the step effect as the different rates of wear between the different (softer on the shoulder, harder in the center) compounds on multi-compound tires, claiming the Interact’s single-compound will wear and perform more consistently from center to edge.
Mmmm… Tire taste test
Though the Interact was launched in Europe a few months ago, the new tire made its official U.S. debut last week. American journos were invited out to always-sunny Palm Springs, CA, for a taste test of the new Interact.
A variety of roads were sewn into our route: city surface streets; smoothly paved, wide-open and flat country roads; undulating, tight radius canyon corners with plenty of rough pavement. My volunteer steed for this tire sampling was a 2009 Ducati Multistrada 1100S. Though it’s impossible to fully assess a tire’s character in a single day, my sense was that the Interact operates just as advertised.
The buns came up to temp quickly, allowing as much lean angle as I dared – I did go all the way to the rear tire’s edge, in case you’re wondering. However, the two traits I was most impressed by were overall handling and ride comfort. Tipping into a turn from full upright to boot toe-scraping angles was one fluid motion, with no detectable transitions in the tire’s profile. That quality means a predictable ride, and a predictable ride equals confidence.
A 150-mile journey from Palm Springs meant plenty of superslab droning for me. This is an excellent environment in which to get a sense of how a tire impacts a bike’s stability, and if it can isolate the rider and bike from road imperfections without numbing feel. I’m happy to report that the Interact scores high marks in both areas. The tires soaked up as much cracked and jagged pavement I could throw their way at more than 80 mph, without protest.
So what’s the correlation between our current economy and the new Interact? Seems mighty Metzeler was able to bring this all-new tire tech to market with a nominal 2-percent price increase over the previous Roadtec Z6. Prices vary widely between vendors, so do your homework and comparison shop. Furthermore, Metzeler claims the Interact will meet the same mileage as the old Z6 but continue to perform at optimum levels all the way to the end, thereby adding value to the new Interact.
Metzeler for President!
Sizes currently available are: 120/70-17 fronts; 160/70-17, 170/70-17, 180/55-17 and 190/50-17 rears. Metzeler says a wider selection will be available by this summer.