TTI speaks to Dalia Broggi, scientific project manager at the European Commission, ahead of her presentation ‘Are your tires compliant when worn? Testing the new regulatory requirements’ at Tire Technology Expo 2024 (March 19, 20 & 21) in Hannover, Germany.
What is your presentation about?
A new amendment to UNECE Regulation 117 introduces requirements for wet grip of worn tyres to assess tire performances at the end of their life. For type approval, artificially worn tires are generated by mechanically removing tread material (i.e. buffing). To assess how well a buffed tire replicates a naturally worn tire, we tested four tire models comparing new, naturally and artificially worn samples of each model. We carried out the regulatory test and other representative dynamic maneuvers.
What are the implications of the new regulatory requirements on tire design and development?
The purpose of new regulatory requirements is to ensure that tire performance is also assessed at the end of a tire’s life in its worn state and to promote the idea that tires should meet the requirements throughout their life and not be replaced prematurely. Therefore, tire design should focus even further in delivering better performance not only on new tires but also on worn ones, particularly on wet braking. This may require additional studies on a tire’s wear and aging mechanism and increased physical testing of worn tires during the development phase.
Why is it important to assess tire performances at the end of its life?
Tire performances may change drastically as they wear. It is therefore important to assess tire behaviour not only when they are new …