The HTR Z5 is Sumitomo's Ultra High-Performance Summer tire, crafted for drivers of sports cars, sporty coupes, and performance sedans who demand sharp handling and dependable traction in warm, dry, and wet conditions. However, like all Ultra High-Performance Summer tires, the HTR Z5 is not designed for use, storage, or servicing in near- or below-freezing temperatures, nor is it suitable for snow or ice.
This tire features an advanced summer-specific compound formed into an asymmetric, five-rib tread design. The continuous center rib enhances stability and steering precision, while robust shoulder blocks boost cornering grip. Notches in the intermediate and center ribs, combined with the compound, provide wet-road traction, while four wide circumferential grooves and lateral shoulder grooves work to channel water away from the tread to reduce hydroplaning risk.
Internally, the HTR Z5 is constructed with a two-ply polyester casing reinforced by two high-strength steel belts. A full-width nylon cap ply increases high-speed durability, and a high-modulus bead insert fortifies the sidewall for improved handling performance.
Important Note: Tires exposed to temperatures at or below 20°F (-7°C) must be gradually warmed to at least 40°F (5°C) for a minimum of 24 hours before any flexing activities, such as adjusting air pressure, mounting on wheels, or supporting vehicle weight.
Flexing Ultra High-Performance Summer tires in cold conditions can lead to permanent rubber compound cracking. Such cracking is not covered under warranty, as it results from improper storage or use. Tires with compound cracking must be replaced.