Metzeler’s newest sport-touring tire, the Roadtec Z8 Interact, joins its Racetec K3 track tire and Sportec M5, completing the Interact family. Metzeler’s patented, zero-degree steel belt technology manipulates two variables to tune the characteristics of the tire and its ability to generate or shed heat to specific needs.
It’s sort of like a guitar string. Adjusting the tension applied to the steel cords wound onto the circumference of the tire’s carcass can vary a tire’s stiffness and level of grip. Combine this belt-winding tension with a varying number of winds per inch, and Metzeler is able to control the amount of tire flex, the size of the contact patch, and the amount of heat a tire generates.
The Roadtec Z8 features a three-zone design, with a firm center for durability. The sides of the Z8 are softer for more heat and better grip to put down an 8 percent larger footprint when leaned over. Metzeler claims the compound allows for faster warm-up on cool days while maintaining a higher level of performance in high-heat situations. The tread is designed for enhanced wet-weather performance, and the tire’s rounder profile increases stability and improves handling.
The tires gave admirable grip on all the bikes on which I tried them: Sprint GT, Z1000, Shiver, and a CBR600RR. The Z8s exhibited confidence-inspiring manners, quick steering, and mid-corner stability — and they warm up quickly on chilly, drizzly mornings. Although the roads were never soaked, road conditions often transitioned from wet to dry. The Z8s stuck well, and if they did slip, traction was regained without drama.
Metzeler’s Z8 Interact tires are available now in 120/70ZR-17″ front and 180/55ZR-17″ and 190/50ZR-17″ rear. A special version of the 180/55″ and 190/55″ rears is produced for sport-touring bikes with an unloaded weight over 530 pounds. —Evans Brasfield
Hard Data: Metzeler, Z8 Interact, Front, from $173; rear, from $208, www.MetzelerMoto.com
Story as printed in the January/February issue of RoadBike.