Though the riders competing in the 2015 MotoGP championship have all departed, the factories stayed on at Sepang for another day of testing. For the fourth day of the first Sepang MotoGP test was designated as a test day for Michelin, who are due to take over as official tire supplier from 2016.
The legal complications of the change from Bridgestone to Michelin mean that the tire test is shrouded in confidentiality, rather than secrecy. This test features only the test riders, all of whom have been barred from talking to the press about the tires. Times were not recorded, and definitely not released, though a handful of hardy journalists stood at trackside with handheld stopwatches (or smartphones) and tried to time riders that way. The secrecy is understandable: Michelin are at a very early stage of their development, and Bridgestone are paying Dorna a hefty sum to be official tire supplier, and want to reap the marketing benefits that should bring.
Yet there were things to be learned from the Michelin test at Sepang today. Unofficial timing from people at the track suggests that riders were lapping somewhere between 1 and 2 seconds slower than they were on Bridgestones. Hiroshi Aoyama was the best benchmark, having ridden throughout the previous three days on a Bridgestone-shod Honda RC213V factory bike. His pace suggest that he is a little over a second a lap slower on the Michelins than on the Bridgestones. Given the newness of the project, and how much data and development Bridgestone have, Michelin appear to have done a pretty good job.
More worrying were the number of crashes at the test. Riders on Hondas, Yamahas and Suzukis all went down hard at Turn 5, the fast left hander at the back of the circuit. Michelin had told the teams to take it easy through that corner, but the riders still went down. The problem appears to have been the front tire in that section, which was wanting to tuck through the corner.
The purpose of the test is to narrow down the selection of tires to bring to the next test at Sepang, when the official riders will get their chance to try the tires. Michelin manager Piero Taramasso told a group of reporters that they had brought seven different front tires and five different rear tires, with the objective of whittling that down to three fronts and three rears for the factory riders to use at the second Sepang test. The feedback from the factory riders will then help define the direction which Michelin will follow for their further development. The basic construction of the tires - casing, compounds, profiles - will be finalized in July. For 2016, Michelin hope to bring three different compounds front and rear for each rider to use at each Grand Prix.