BMW has chosen the Michelin Pilot Sport 4S* (PS4S*) as a 21-inch summer tyre fitment for its new high-performance X3 M and X4 M models.
The new BMW X3 M and X4 M Competition models, which are fitted with the 21-inch light alloy wheels, will be equipped with Michelin PS4S* 255/40ZR21 102Y front and 265/40ZR21 105Y rear ultra-high-performance tyres. These feature a number of Michelin technologies, including multi-compound tread patterns and an aramid-reinforced casing design. The tyres are star-marked (*) to signify that they are homologated BMW fitments.
These tyres are, the company says, the result of almost three-years of co-development between BMW M and Michelin. During this development phase around 800 prototype tyres and 1,400 pre-production tyres were produced and tested at the Nurburgring in Germany, and Miramas and Ladoux test tracks in France.
The front tyres feature Michelin’s tri-compound technology and the rears are bi-compound. Originally developed for endurance race tyres, multi-compound technology uses different rubber compounds on different parts of the tread to fine tune the performance. For example, the outer shoulder is designed to provide exceptional grip and wear resistance during cornering, intermediate ribs are optimised for steering and handling, and the inner shoulder is designed to break through water and provide grip on wet roads.
When developing the tyres, BMW M’s engineers asked Michelin to concentrate on dry performance, high grip levels, good track endurance and good balance on wet surfaces, all while maintaining the BMW M signature sporting feel at the steering wheel. The fact that the front and rear tyre sizes are similar meant Michelin had to engineer the different characteristics with only the tread pattern and the compounds to ensure the design brief was met.