Technological, materials advances help Hankook commercial tyres to 10%-plus improvements

Hankook’s AH51 and DH51 tyre performance ‘exceed expectations’, with wet grip, mileage, rolling resistance, fuel efficiency improvements, while SmartLife technology offers up to 250% mileage life from new tyres

Hankook SmartFlex AH51 (Photo: Hankook)

The key performance characteristics of Hankook’s AH51 and DH51 truck tyres are recording double-digit improvements across the board versus their predecessors, the manufacturer states. Advancements in computer processing power, AI, materials science and 3D printed mould technology have helped Hankook produce truck tyres with a stepped change in performance throughout the life of the tyre. The manufacturer says its investment in these combined technologies has resulted in a cooler running tread, a more rigid tread block and “regenerating” tread features – a tread pattern that evolves as it wears – resulting in significant fuel savings, damage resistance, wet grip and higher mileage for premium fleet partners.

Both new tyre patterns are achieving extended longevity. Hankook says the AH51 steer tyre delivers 15 per cent longer mileage, while the drive axle mounted DH51 offers 20 per cent higher mileage, while reducing rolling resistance by 10 per cent, contributing to better fuel economy. Wet performance is 15-17 per cent better than the 31 series product, which in testing in the part worn condition gave a 6.3m shorter stopping distance than the lowest-placed premium competitor’s current generation, Hankook adds. It puts this improvement down to its 3D mould printing, which has enabled the “regenerative” tread pattern of the 51 series products.

Hankook’s SmartLife Solution also increases the life of each new tyre by up to 250 per cent; the AH51 and DH51 are designed specifically to be regrooved and retreaded, allowing for up to four life extensions. These features contribute further to the cost per kilometre of each tyre. Hankook tested the AH51 and DH51 around Europe in 2022, and as a result of its successes is phasing out the preceding 31 Series to allow existing and new fleet partners to benefit from its latest generation of truck tyres.

“As a company, we place a high value on the sustainability of our products, and therefore our newly developed smart treads fulfil our aspirations for ensuring sustainable and future-proof tyres, and of course also in conjunction with significantly increased customer benefits,” says Jon Cottrell, Hankook UK‘s TBR manager. “Intensive testing has shown that, compared to competitors in the premium category, both new SmartFlex products achieve significantly higher performance standards in the lifetime performance chapter, even when the tyre are two-thirds worn, for example in terms of braking distance on wet roads as well as grip and safety in a wide range of road conditions.”

Hankook’s SmartFlex line is particularly suitable for regional and local traffic distribution. Tyres come with Three Peak Mountain Snowflake certification for year-round performance. The SmartFlex AH51 (steer) and DH51 (drive) also benefit from Hankook’s advancements in sustainability and tread technologies bringing further improvements to tyre performance.

Both tyres feature a base compound designed for efficiency. Hankook increased the proportion of low-damping materials, contributing to the reduction of principle viscoelastic power loss throughout the tread. As a result, less energy is lost, and fuel efficiency is improved. The sidewall compounds were also freshly developed for the new SmartFlex generation. Hankook’s developers emphasised significantly increased resistance to crack formation and material fatigue, improving the tyres’ carcasses for increased life and suitability for extended life processes. The new DH51 also incorporates high-performance resins in its notch-tough tread compounds, boosting durability by increasing the molecular weight of the polymers used. This contributes to the tyre’s higher mileage performance.

Hankook’s Innovative Mixing System (IMS) distributes carbon black particles and rubber molecules evenly within the compounds. Combined with extended mixing times at lowered temperatures, Hankook says it has increased the bonding rate between the carbon black and rubber molecules, allowing its SmartFlex tyres to generate less heat during operation.

Hankook SmartFlex DH51 (Photo: Hankook)

The SCCT (Stiffness Control Contour Theory) design technology used in SmartFlex products ensures that the internal pressure distribution is as evenly balanced as possible depending on the application. This results in more stability and less movement in the tyre casing during use, which leads to high durability of the SmartLife carcasses and very good retreadability. For both the belt plies and the carcass itself, the AH51 and DH51 each use special high-strength steel cord materials. Together with the SCCT contour, this results in a consistent contact patch for even wear, as well as improved traction and braking performance.

3D sipes with self-regenerating tread features incorporated into the AH51 and DH51 treads emerge after a degree of wear of between 40 and 70 percent in the tread pattern. The task of these “regenerating” grooves is to lock the tread blocks together in the rolling movement and thus ensure higher overall tread stability and thus resulting in extended mileage over the entire service life. They also make the tyre more robust and less susceptible to external influences, such as poor road surfaces. So-called “hidden grooves” appear from a wear level of around 70 percent and ensure continued high traction and wet grip even in wet conditions until the tread is completely worn out.

The wide tread blocks of the SmartFlex AH51, which can also be used as an all-position tyre, are equipped with additional supports, which Hankook calls a Tread Wear Equalised Stepper (TWES) in the outer grooves. This increases tread stiffness in conjunction with the tyre’s broad tyre shoulder ribs, ensuring even wear across the tread and improving tread life and fuel economy characteristics. The SmartFlex DH51 has a wider contact patch than its predecessor, which increases traction while improving mileage and rolling resistance. Special sipes on the shoulder blocks, which naturally are under stress on drive axle tyres, help to reduce cracking even during peak loads. In addition, they support tread drainage to further increase traction performance.