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The new range of truck tyres with Zenvironment technology has been expanded with a product for steering axles. Designed for long hauls, but also suitable for regional use

Mino De Rigo

GIVE MORE mileage with even wear maintained for longer, improve the retreading option and, overall, reduce consumption and running costs. These factors are at the root of any haulier’s requests and Yokohama has revolutionized its approach to them: new product and process technologies that are part of a vision with the fascinating title of Zenvironment. The aim behind the Zen-environment crasis, a metaphor for solutions inspired by sustainable mobility that is a blend of the ideal model and reality, is to lead the entire truck range back to a new project and production ideal by the end of next year. The champion of this technological renewal is the new long-haul tyre for steering axles, 107ZL.
The latest addition to eco-friendly Zenvironment products” – explained Fabio Merli, truck sales director at Yokohama Italia – “boasts a casing construction, tread pattern, compounds and technically-advanced manufacturing processes that will give better fuel economy and save waste and pollution. This is also reflected in reduced costs for users”. Because of the difficult economic situation, hauliers are constrained to choose between the most advantageous medium-term solution and the immediate savings offered by the increasingly numerous budget tyres.

A boost for a depressed market
The figures for the Italian market and its ongoing impoverishment are discouraging. In this context, the acceleration of a premium brand may seem to be paradoxical, but our company operates in a global scenario and its actions today are the competitive key to tomorrow’s recovery” – Fabio Merli explained. In the meantime, positions must be maintained, “but without undermining the value of a highly technological offer: a range with the Zenvironment label that already embraces regional and long-haul summer and winter tyres in various sizes with low rolling resistance and increased longevity, and they are easier to retread”.
At the basis, first and foremost, is a compound mixing process that is carried out at lower temperatures compared to the traditional method, with rubber amalgamation carried out by special rollers during a subsequent stage. The separation of these two stages also prevents the premature hardening action of the carbon black, which takes away the energy required for spreading the molecules; this prevents the breakage (and subsequent concentration) of the long chains of polymers to the advantage a more even distribution of the rubber mixture and the additives in the compound. The result is a stronger, more flexible product that will increase tread durability and the useful life of the casing.

Zenvironment and technological trump cards
Another technological trump card is the computer simulation of casing profile expansion caused by the heat generated during use. The anti-age recipe involves the use of profiles that take into consideration the stresses to which the inside of the tyre is subjected before its shape is stabilized, which usually takes place between 40,000 and 50,000 km, so that the tread contact patch (assuming that tyre pressures are correct) is always even. An equally important role is played by the new, lighter, less permeable internal liner that was designed to prevent tyre oxidation and the resulting deterioration.
They are developments” – Merli added – “that are common to the entire Zenvironment family and are part of a wider strategic programme called Grand Design 100: the aims that have been set for 2017, the company’s centenary year, include the establishment of the brand on the global market, the increase in production capacity to 2.5 million truck tyres, offer expansion and diversification (also in the retread segment), and ethical and environmental commitment”. The special characteristic of the new 107ZL appears to be versatility, primarily, due not only to the compounds but also to the tread solutions adopted. “In point of fact, the product was created for long hauls, but it performs equally well when used regionally. Much more so than its predecessor, the RY637, because it provides additional opportunities for hauliers who must adapt more than ever before to the requests of contractors”.

Operation longevity and savings
In the first place, over 6,000 sipes on the edge of the tread ribs (respectively, six in the 315/70 R22.5 size and five, separated by four longitudinal grooves, in the 295/80 R22.5 and 315/80 R22.5 sizes): small grooves at the tread edge reduce contact pressure and contribute to better heat dispersion. This also limits the uneven wear typical of tyres that are subjected to stresses on the same point at the rib edges due to being driven for long periods on straight stretches: heat is retained with the consequent waste of energy (and fuel) and irregular, zigzagging wear.
Another key solution to reducing stepped wear of the tread shoulder are the special lugs that increase the surface exposed to air for better cooling, which also makes it more deformable to optimize the contact patch and stabilize the entire tread. “It is a technical aspect the previous model RY637 also had, but with different geometries: in this case they are shallower to prevent the shoulder mobility that occurs when the tyre is not used correctly (regional) and causes the edge to wear prematurely. A difference that emphasizes the versatility of the new 107ZL”.

Durability tests
Completing the picture is the zigzag section of the external longitudinal grooves that prevent gravel and stones from lodging and the sequence of special lugs at the bottom of the internal channels, which expel small stones when the wheel is rolling and limit possible damage.
The distance tests” – Merli emphasized – “performed on 8 Man tractors with the new 107ZL in the 315/70 R22.5 size were compared with the previous RY637. Thanks to a 27% increase in mileage, they showed greater durability with estimated tread wear  up to the 3mm limit”. Available this month in the three sizes already mentioned, the 107ZL costs about 5% more than the RY637.

106ZS – and the Zenvironment range grows again
The range with Zenvironment technology has another truck tyre on the launch pad: the new 106ZS for steering axles and regional use. The two sizes, 385/55 R22.5 and 385/65 R22.5 which will be on the market by September, feature six wide longitudinal ribs edged, like the shoulders, with sipes to the advantage of resistance to wear. With a robust casing suitable for retreading, the new 106ZS truck tyre is part of the project philosophy that aims at longevity and the guarantee of even tyre wear and low rolling resistance for efficient, less costly driving. Without a doubt, this is the most important aspect for long-haul vehicles: for trucks that travel thousands of miles a week, the savings in running costs achievable with energy-saving tyres that can also be retreaded easily, can really make a big difference.

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