Metzeler Roadtec Interact Z8 Tire Review
Using belt tension to fine-tune tire performance
According to Metzeler, the German tire company can manipulate the performance of its motorcycle tires by adjusting the tension of the tire’s steel cords. Metzeler calls the process Interact technology, first seen two years ago in the Z6 Interact sport-touring tire (reviewed here), and has imparted the new-for-2011 Roadtec Z8 tire with this technique.
Between the carcass and external compound of a Z8 tire resides more than 120 steel cords. Like a string instrument, each cord can be tuned to produce a different effect. In the case of the Z8, the result is better grip and tire longevity rather than tonality.
The Roadtec Z8 boasts three tension zones: the center and two sides. To deliver the highest mileage possible, the tension of the cords in the center zone is high. For maximizing grip, the tension of the cords in the two side zones is reduced. It’s said to offer the benefits of a dual-compound tire while using just a single compound.
“The compound interacts with the tension of the wire,” explains Metzeler’s senior test rider, Alessandro Abate. “The higher the tension the less the tire’s compound will move. The lower the tension the more flexible that part of the tire will be.”
To simulate real-world conditions, Abate, a former Italian national roadracer, travels to Metzeler’s purpose-built tracks located in various regions around the globe. In the course of developing the Roadtec Z8, it’s Abate’s job to ride pre-production tires with a variety of cord tensions and decipher which is the best combination of tensions.
“Depending on the tension of the cord a tire can feel over-inflated or under-inflated,” says Abate. He also provides feedback on a tire’s carcass strength, durability and, of course, grip.
Compared to the Z6 Interact, the Z8’s new design is said to offer much better handling, with improvements also to levels of traction in both wet and dry conditions.
Metzeler gave us a chance to try out the new Roadtec Z8s on a variety of motorcycles during a damp, cool day. Since the Z8s are classified as sport-touring tires, it seemed appropriate to choose bikes befitting of the title, so miles were accumulated on a BMW K1600GTL, a Kawasaki ZX-14 and a Ducati Multistrada 1200. (Roadtec Z8s are original-equipment fitment for BMW's K1600s and feature stiffer sidewalls and a second ply to better handle the bike’s weight. All other Z8s are of the same construction.)
Sportiest of the big touring rigs, the Z8-shod Beemer ground pegs while strafing the tight corners in the coastal mountains above Malibu, California. It was my first time aboard the new K and I couldn’t get enough of the performance, and especially the sound of the new inline, six-cylinder engine, and I commenced riding it more like a sportbike than its intended purpose. Never once did the Z8s allow the big bike to step outta line or give me worry as I worked the tourer through the twisties.
“I was shocked at the nimble characteristics of the K1600 when I rode on them a few months ago,” says Duke about the Beemer’s press launch. “Part of it is due to the bike’s relatively light weight and sorted chassis geometry, but the well-mannered Z8s also deserve credit. I also rode the GT version of the K1600, and the tires hung in past the point of scraping its higher footpegs.”
Next up was the sportier and more brutish ZX-14. With this bike it was easy to overpower the grip of the rear Z8, but the few times it did light-up, the feeling was never one of losing control. Even on the damp, overcast side of the mountains the Z8s maintained composure while I descended in elevation to ocean-level aboard the big ZX.
As one of my personally favorite bikes, I was looking forward to riding the Ducati Multistrada on the final portion of the trip. This was the tightest, most aggressive riding of the day, and my appreciation and familiarity with the performance of the versatile Ducati allowed me to really push both the bike and the tires. After this hard-charging leg of the trip was over, I was really impressed by the grip of these so-called sport-touring tires.
The performance and grip of the new Roadtec Z8s is quite impressive, especially for sport-touring rubber. Our day on the Z8s didn’t reveal much about the tire’s durability, but Metzeler says to expect slightly better mileage than the good-wearing Z6.
For sporty riders looking for tires with tenacious grip and extended endurance, Metzeler appears to have delivered an excellent combo in the Z8.
The Roadtec Z8s are available in eight typical 17-inch-diameter sizes. Front sizes are 120/60-17 and 120/70-17, while rears range from 150mm to 190mm wide, including the recently popular 190/55-17.
|Metzeler Roadtec Interact Z8 Pricing|
|Front Tires||$174 - $179|
|Rear Tires||$209 - $270|