New-generation dumptruck tyres from Michelin
First published in the November 2017 issue of Quarry Management
Michelin say the increased payload potential of their new rigid dumptruck (RDT) tyre range is reflected in the product name – Michelin XTRA LOAD. Designed for use on 40–80-tonne payload RDTs, the XTRA LOAD is said to be the first-ever ‘three-star’ 24.00R35 tyre range on the market. Whereas previously most 24.00R35 tyres carried a ‘two-star’ rating, Michelin say the new XTRA LOAD range offers an increase of 9 tonnes in load capacity per machine and can deliver a significant increase in productivity when multiplied by the number of cycles made daily.
The XTRA LOAD tyre is available in two variants, targeted at the two main surfaces experienced by rigid dumptrucks: Michelin XTRA LOAD Grip – for use in soft, loose, muddy ground conditions, as often experienced in mining and quarrying operations on slopes/inclines, where the priority is high grip and traction; and Michelin XTRA LOAD Protect – for use in hard, sharp abrasive conditions on flat, dry surfaces where the priority is protection and damage resistance, such as quarries and construction sites.
Both variants are said to benefit from greater wear life and increased productivity thanks to an 8% improvement in wear resistance and an improved TKPH (tonnes km/h), compared with their predecessors. For the new XTRA LOAD Grip and XTRA LOAD Protect, the TKPH is increased by at least 20.3% and 13.8%, respectively, in the A4 compound, and by at least 11.7% and 41.7% in the B compound, compared with previous Michelin ranges.
Michelin have also recently unveiled a damage-resistant E4 tyre range for articulated dumptrucks (ADTs) with payloads between 25 and 45 tonnes. Known as XTRA DEFEND, the new premium E4 deep-tread tyre has been specially designed to deliver improved robustness to minimize damage and machine downtime, and optimize operating costs.
Initially available in 23.5R25 and 29.5R25 sizes, Michelin say new range will meet the challenges and requirements of an E4 ADT tyre in all applications and conditions. The XTRA DEFEND is designed to perform and improve productivity both in the harsh, aggressive environments of mines and quarries, and in the high-speed/high-cycle activities of construction and public works.
The tyre takes its name from the much-improved robustness and damage resistance, which are the result of 15% thicker sidewalls and the casing’s increased resistance to penetrations, with the Michelin XTRA DEFEND capable of driving over a 172mm spike without sustaining a puncture – 16mm more protection than its premium competitors.
Having improved the robustness and strength of the casing, and with 15% thicker sidewalls, this ‘protective shield’ has allowed the tread depth of the tyre to be increased. The 29.5R25 XTRA DEFEND tread pattern, for example, is 65mm deep – 5mm more than its predecessor, the X-Super Terrain+. Moreover, the overall volume of rubber used in the tread has been increased by 17% compared with the X-Super Terrain+.
According to Michelin, both of these improvements result to a 15% increase in tyre life. Yet despite these improvements to the tyre, Michelin say ADT productivity – maximizing speed and load carried – has not been impacted: the tonnes km/miles per hour (TKPH) of the new tyre is the same as the previous generation, and higher than its competitors.
The Michelin XTRA DEFEND will be available in replacement markets during the fourth quarter of this year, and for OEM specifications from the first quarter of 2018. Next year will also see the introduction of 26.5R25, 750/65R25 and 875/65R29 sizes.
For more information visit: www.michelin.com
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