Each individual steel belt is tuned like a guitar string. Low-tension zones increase the c
Like desperate housewives scrutinizing each other’s Starbucks orders, motorcyclists can be critical of each other’s tire choices. Slapping high-mileage touring tires on a Suzuki GSX-R or high-grip race rubber on a BMW F800R is a bit like ordering a Venti Latte with whole dairy instead of soy milk. Noses will wrinkle. Metzeler, however, sees nothing wrong with either scenario. The motorcycle-exclusive tire manufacturer operates under the outrageous assumption that what really matters when choosing the correct tire is how you use your bike. With the new Roadtec Z8 sport-touring tires joining the excellent Sportec M5 and Racetec K3 offerings, Metzeler now offers premium Interact sport radials for the full spectrum of sport riding.
This past April, we traveled to Cartagena, Spain, for Metzeler’s “Interact Challenge,” where we sampled all three types on a wide variety of sport-oriented motorcycles. Rather than multiple tread compounds, Interact technology uses a single compound and instead manipulates carcass stiffness via belt tension to enhance grip. The result, Metzeler claims, is more consistent and predictable performance without the abrupt transitions of a dual-compound tire.
We began at the Circuito Cartagena aboard a Sportec M5-equipped GSX-R600. These tires use five tension zones: a high-tension center for durability, low-tension shoulders for cornering grip and high-tension edges for precise steering. We immediately noted improved rear grip compared to the stock Bridgestone BT-016s, likely related to Metzeler’s 55-percent silica compound and track-derived resin blend. The stiffer M5s also carved the bowl-like Turn 12 with extreme precision, though the “increased” feedback bordered on roughness at the very edges of the tires.
While they stuck like glue under the lighter, less-powerful 600, the Sportec M5s gave the BMW S1000RR’s traction control a real workout—explaining why the stickier Racetec K3s are OEM fitment on that massively powerful superbike. The K3s feature a low-tension center for maximum acceleration and braking traction and high-tension sides for maximum stability under cornering load, with a softer, track-specific compound trading longevity for outright grip. The K3s gripped like gorilla glue on a Suzuki GSX-R1000, and the aggressive front profile turned the slow-steering Gixxer into an apex predator.
The Interact’s PiI symbol-inspired tread design has been scrutinized just as closely as th
If the Sportec M5s were overstressed on a hot racetrack under a mega-powerful literbike, they were at home on Triumph’s Speed Triple during the afternoon street ride, delivering easy, neutral steering and enough traction to wheelie out of tight corners. But the new Roadtec Z8s were the biggest surprise. A durable, high-tension center and traction-enhancing low-tension shoulders conspire here with a high-silica “nano-particle” compound engineered to perform equally well on hot days or in cold, wet conditions. We noted little difference in street performance compared to the M5s, with quick turning, exceptional rough-road stability and plenty of rear grip—at least on a mid-powered Yamaha FZ8. If the Z8s indeed wear longer than the M5s, these could be the sport tire value of the year.
So go ahead: Drink that milk fat. Take that BMW to the ractrack, or tour on a GSX-R. Just pick the proper tire first. Metzeler’s Interact lineup has whatever you need.
METZELER INTERACT TIRES
PRICE: Roadtec Z8 $165.95-$250.95, Sportec M5 $171.95-$291.95, Racetec K3 $221.95-$394.95
VERDICT 4 out of 5 stars
Now sport riders of every stripe can enjoy the benefits of Metzeler’s Interact technology.