Goodyear adds a plus, subtracts rolling resistance
You need to look carefully to spot the ‘+’ sitting alongside the familiar Marathon name, yet the addition of this symbol is said to represent a sizable decrease in rolling resistance and thus reduced vehicle operating costs. Goodyear has introduced its latest generation commercial vehicle tyre range, the Marathon +, and says rolling resistance in its new LHD II+ and LHS II+ drive and steer tyres is seven per cent lower than in their predecessors.
Every reduction helps; Goodyear comments that in some cases fuel costs represent 34.9 per cent of total vehicle operating costs, while tyre expenses add a further 2.4 per cent. This is, it says, ample incentive to focus on technology that cuts consumption – so long as it doesn’t result in a compromise in mileage and wet grip qualities. To achieve the said seven per cent improvement in rolling resistance over the predecessor LHD II and LHS II, Goodyear used a tread compound enhancement it calls Silefex. This newly introduced substance was developed in the Goodyear Innovation Center Luxembourg and is described as containing “an optimised blend of silica fillers and premium natural rubber.”
Thanks to the use of Silefex, Goodyear calculates that replacing a combination of Marathon LHS II, LHD II and LHT II with LHS II +, LHD II + and LHT II could represent a one per cent reduction in fuel consumption. So for a truck and trailer with a fuel consumption of 32 l/100km, a fuel price of £1.20 per litre and an annual mileage of 120,000 km or 74,500 miles, the saving would be £500 per vehicle, per year and a 1,000 kilogram reduction in CO2 emissions.
Favourable feedback from TÜV Süd
In August and September 2011 the technical services company TÜV Süd compared the Goodyear Marathon LHS II + / LHD II / LHT II with three main competitors. Goodyear hasn’t disclosed which competitor products were used in the TÜV comparison but the sizes tested were 315/70R22.5 for the steer and drive axle fitments and 385/65R22.5 on the trailer axles. A key objective of the test was to determine the comparative rolling resistance of the tyres, and rolling resistance ratio calculations were based on a load distribution of 17 per cent for the steer axle, 25 per cent for the drive axle and 58 per cent for the trailer axle. Goodyear reports that rolling resistance for the LHS II+ steer tyre was found to be between three and 19 per cent better than the competition while the Marathon LHD II + was in one case equal to the competition and in the other cases up to 16 per cent better. The Marathon LHT II trailer tyre was between 12 per cent and 28 per cent better than the competitors.
The TÜV Süd Automotive report (76246886-1) from the comparative test also covered wet grip; the wet grip index was measured with steer tyres on the front axle and drive tyres on the drive axle and a loading of 6,600 kilograms on the steer axle and 11,200 kilograms on the drive axle. Goodyear relates that the results show the Goodyear combination stopped shorter than the competitors’ tyres in all cases – in once instance 0.9 metres shorter. The average performance of the Goodyear combination braking on wet asphalt was said to be two per cent better than the competitor tyres.
Testing the Marathon +
Goodyear says it worked closely with Mercedes-Benz Trucks while developing the Marathon + range and the vehicle manufacturer conducted numerous tyre tests, including those for tread wear and wet grip. The Marathon LHS II + and Marathon LHD II + were also sent out on field trials with several fleets over a period of 18 months and were employed in commercial long haul operations using Mercedes-Benz Actros 1844 and 1841 models.
An initial line-up of four LHS II+ and one LHD II+ sizes has been launched and further additions to the range will be made in the first and third quarters of 2012. The Marathon LHT II is available in three sizes. Goodyear says it is currently introducing the Marathon + range to all major OEMs to highlight the benefits that it offers as an original equipment tyre.