Discover more about the topics and technologies to be discussed at this year's conference, via a series of exclusive interviews with a selection of our expert speakers
Frédéric Biesse, tire performance analysis expert at Michelin, introduces the tire giant’s quest to learn more about the behaviour of worn tires – particularly in wet conditions. As it turns out, worn tires from different manufacturers vary greatly in performance, but predicting worn tire performance and communicating it to consumers and law makers can be a dark art.
Tell us about your approach to testing wet performance of worn tires and what you have learned from it.
The first thing to mention is that the testing of worn tires is a relatively new idea in the tire community, but several tire manufacturers have recently started doing it. Michelin believes that for consumer safety, we should test the performance of worn tires. After all, by the law of averages, all cars on our roads have half-worn tires. The evolution of tire performance with wear is well known, with dry grip improving by 5-10% and rolling resistance improving by up to 20%. In other words, a worn tire has a shorter braking distance on dry roads and consumes less fuel, but wet braking performance suffers. It takes longer to stop on wet roads, so this is our focus.
Our approach had two main goals. First, we wanted to test tires when worn to the legal limit (1.6mm), analyse the results and understand the mechanisms at play – including hydroplaning. Second, we wanted to fully understand wet road conditions, rainfall levels, resulting water depth on roads, how this influences driver behaviour and speed. We therefore also looked at accidentology studies about wet conditions.