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05/09/2011
Ground to be gained

Michelin XDR2 for rigid dumpers

Mines and quarries are ground to be gained by the French company's new tyres accredited with lower TCO compared to their predecessors and, in addition to increased safety, less impact on the environment, as demanded by its comprehensive range renewal strategy
 

Mino de Rigo

The sizes of the new product range from 27.00R49 to 63 inches (53/80 and 59/80) and, as they gradually become available, also 33.00R51, 37.00R57 and 40.00R57.

 

Already capable of putting the crisis behind it, the quarry and mining sectors represent for the world market of earthmoving tyres just as many strongly developing segments characterized by two-figure growth and with emerging countries driving the group. The first sector is very active in Italy, but the second is less significant: together, they are the new target of the Michelin XDR2, a tyre for rigid dumpers working in mines or quarries on particularly difficult terrain and, above all, an important new addition to the renewal strategy for the entire product range. Giovanni Petrillo, head of marketing for earthmoving and industrial transport at Michelin Italia, explained: "The goal is to be present on the market with three types of tyres for rigid dumpers: the first typical quarry tyre where traction is a priority is X-Traction and its range has been expanded with new sizes; the second is for quarries and building sites where loads have to be moved faster, X-Quarry S ("S" stands for speed), and the third is the new XDR2" developed specifically for surface mines but also suitable for other applications where working conditions are very difficult. "Italy does not have the greatest vocation for mining, but Michelin does not exclude any market".

 

C2 lengthens casing life
The sizes of the new product range from 27.00R49 to 63 inches (53/80 and 59/80) and, as they gradually become available, also 33.00R51, 37.00R57 and 40.00R57. "The directions taken for the development of the XDR2 correspond to the main declared aims for the sector: operator safety, containment of total cost of ownership (TCO), and less impact on the environment. They are all aspects for which the new tyre has taken decisive steps ahead compared to its predecessor XDR". In order to lower TCO, the men at Michelin worked on various features: firstly, they created casing architecture based on C2 technology, which has been successfully used in the new sizes of the X-Traction, because the tyre doesn't get so hot so its useful life is lengthened. "Even though rigid dumpers work at relatively low speeds of between 10 and 30 km/h in quarries" - Petrillo pointed out - "the bulk of the vehicles and their cargoes makes the tyres heat up considerably, so they tend to deteriorate faster. By using C2 technology, we saw that for the same size, capacity and compound, the XDR2 heated up a lot less than the previous model". With the same purpose, sculptured cooling vents guarantee a more consistent passage of air that helps to keep running temperatures low. "Thanks to the full-depth blocks and a central lug that is 13% larger wider, the contact area has been increased to the advantage of safety and stability.

 

More resistant to cuts and tears
In addition, the tread pattern is self-cleaning and, compared to the previous tyre, it is less likely to retain stones or other material that can eventually damage the tyre". The other key factor that Michelin ascribes to the reduction of TCO is tread thickness, 20% more than the XDR and therefore with a proportionately longer life. And an important contribution is also made by resistance to cuts and rough ground: "To prevent accidental damage and ripping that would lead to early replacement" - the Michelin Italia manager stated - "we worked mainly on the sidewalls and the layer of rubber between the undertread and the protective plies: this layer has been thickened on one side in order to stand up to contact with rocks, nails and other sharp objects: on the other side, the shape of the sidewalls is fuller and more continuous", thereby doubling the thickness and increasing cut and impact resistance. The plies have been strengthened with steel, "which, on the basis of size, makes them up to 60% stronger; moreover, a new rubber moulding process has been used around the steel so that the cavities are isolated individually and any oxidation of one that has been exposed by damage will not spread to the one next to it". As to the compounds, the engineers' choice was influenced by the French company's decision to multiply the options by segmenting the product according to usage requirements.

 

Different compounds for the same product
"We can offer the market the same XDR2 sculpture in the 27.00R49 size" - Petrillo emphasized - "and in three distinct versions, each one with a different compound. So users can choose the product that best meets their applications, with the support of our specialists in the field regarding traction capability, average driving speed, and resistance to aggression". The performance of the variations of the same tyre ranges from maximum resistance to damage, combined with lower driving speeds, to precisely opposite situations with a balance halfway between the two. "The relevant permitted speeds are 18, 22 and 26 km/h, differences that may seem negligible, but they meet very different applications in daily use". Michelin claims progress also in terms of eco-compatibility and accredits the new tyre with less weight: "Even with longer life and superior strength" - Petrillo maintains - "we use less raw materials, it reduces fuel consumption, at the end of its life, there is less product to dispose of. And because the XDR2 lasts longer, fewer tyres are needed to carry out the same job; tyres than can also be retreaded, which further lengthens the useful life of the casing with obvious benefits for the environment".

 

• Earthmoving, a fast-changing range 

 

Complete renewal in just a couple of years for Michelin's quarry range. About 18 months ago it began to change all the models with the homologation of a new generation, starting with the loader tyre XHA L3 which is replaced with the new XHA 2 series, a clear step ahead in performance compared to the previous series. As far as dumpers are concerned, the renewal began with the launch of the X-Quarry S tyres, followed by the presentation of the X-Traction tread pattern for rigid and articulated dumpers to the advantage of the latter, the renewal of the XDR range with the new XDR2, which boast, amongst other things, the possibility of housing electronic sensors controlled by the Michelin Earthmover Management System (MEMS): based on GPS, it constantly monitors the activities of individual vehicles and can be used to plan their work schedules as a function of the data revealed. It is a kind of rangefinder that optimizes vehicle use for maximum productivity without exceeding the tyre's critical stress threshold. By next year, the renewal of Michelin's earthmoving tyres will be completed with the L5 and L4 series, the XLD D2 and XLD D1, respectively, which will offer greater load capacity and a complete change of rating from one to two stars. 

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