Bridgestone and Michelin in Disagreement over Tests
French website autoactu.com has reported details of a conflict between major tyre manufacturers Bridgestone and Michelin over the comparative energy-saving properties of Michelin’s Energy range of tyres. Bridgestone presented the results of an experiment testing Michelin’s promise of reduced fuel consumption when using their Energy tyres. The experiment was carried out at the behest of one of its carrier customers and, as a result, involved head-to-head performance comparisons with Bridgestone’s own conventional tyres. The initial results, said Bridgestone, showed no significant differences in the performance of each tyre. However Michelin were quick to dispute this conclusion, citing 70 tests involving tyres from both organisations, where the Michelin tyre came out on top in terms of fuel consumption and criticising the methodology of the tests, in which the company was not involved.
The test itself consisted of the fitment of new and 50 per cent worn tyres from each company to four identical vehicles. Drivers were then required to make the same 400km per day journey and, after two months, the tyres were swapped for another two months. “After four months,” summarised Bridgestone France Technical Director Olivier Monbet, “it was not possible to demonstrate a difference in terms of consumption between Bridgestone and Michelin.” Monbet, autoactu.com reports, went on to qualify this statement, suggesting that the effects of tyres on fuel consumption could easily be neutralised with other factors, such as driving style, aerodynamics and vehicle maintenance. The results appeared to have drawn into question the idea that tyres with lower rolling resistance could impact meaningfully on fuel consumption.
Serge Dejean, product marketing manager PL Europe Michelin, reacted against the published announcement, stating, “We cannot accept these conclusions.” Dejean reasons that the test methodology “was not valid to achieve an objective outcome”, pointing out that the vehicles fitted with 50 per cent worn tyres consumed more fuel according to the tests, “which is physically impossible.” He also pointed towards the Energy range’s strong performance in over 250 tests since its launch in 1995.
Autoactu.com also explained that the tyre that was subjected to the tests was not the most recent in Michelin’s Energy range, which is named the Energy Saver Green. This tyre, launched with an exclusive fitment on the new Renault Magnum truck, is the third generation in the line, and Michelin have announced that it boasts a reduction in fuel consumption of up to half a litre in comparison with the previous Energy A2.