MotoMatters.com | Kropotkin Thinks

In what is almost becoming a tradition, the resurfacing of the Phillip Island circuit is causing problems for tire manufacturers. This time, it is the World Superbike paddock who are in trouble, as the new surface is causing temperature issues for Pirelli, forcing the both WorldSBK races to be shortened from 22 to 20 laps, and the introduction of compulsory pit stops in both the WorldSBK and WorldSSP classes.

Riders in both classes have been given a three-lap window in which to change tires. In the WorldSBK class, tires must be swapped between laps 9 and 11, while the WorldSSP class will have to change tires between laps 8 and 10.

The decision recalls the 2013 MotoGP race at Phillip Island, where Bridgestone discovered that blisters were developing in its rear slicks when the grand prix paddock visited the circuit for the first time since resurfacing. Compulsory pit stops were also introduce for that race, though the phrasing left sufficient ambiguity for the Repsol Honda team of Marc Marquez to think they could stay out a lap longer than the could, eventually leading to the disqualification of Marquez.

The instructions from Pirelli are clearer this time around, riders must come in on one of the named laps to change tires. In 2013, Bridgestone's instructions were that tires could only do a maximum of 10 laps. Marc Marquez and Bryan Staring interpreted that to mean they could do 10 full laps and come in again on lap 11. Race Direction disqualified them for exceeding the maximum number of laps.

Resurfacing at Phillip Island is always a particular problem because of the nature of the circuit. It is already one of the fastest tracks on the calendar, which places some of the heaviest demands on the tires. The bikes spend a lot of time going very fast on the left side of the tire, putting a lot of heat into the rubber. Add in the extra grip of a new surface and the heat generated can exceed the tires' capacity to deal with it.

There is as yet no word on whether Michelin will test at the circuit ahead of the Australian round of MotoGP in October. But the data collected by Pirelli from the WorldSBK round will be extremely useful to help them prepare the Moto2 and Moto3 races there.

The press release from Pirelli explaining the decision appears below:

Pirelli: the new asphalt at Phillip Island is record-breaking but extremely abrasive

Based on the evidence that emerged over the two days of testing, and to protect the safety of the riders, Dorna, FIM, Race Direction and Pirelli have agreed to carry out races with mandatory pit stops

Over the two days of testing carried out at the Australian circuit of Phillip Island, which will host the first round of the 2024 FIM Superbike World Championship over the weekend, several riders significantly improved on the lap records in both classes: Toprak Razgatlioglu (ROKiT BMW Motorrad WorldSBK Team) was the fastest in WorldSBK, setting an absolute best time of 1'28.511 at the end of FP2 on Tuesday afternoon, while in WorldSSP it was Yari Montella (Barni Spark Racing Team) who set a best time of 1'31.881 during FP2 on Monday.

The new asphalt provides much more grip than the previous surface and has played a key role in obtaining these results. On the other hand, it has proven to be extremely aggressive on the tyres, bringing the tread compound to operating temperatures never recorded before and significantly accentuating tyre degradation.

While Monday's WorldSSP sessions took place in relatively cool conditions, with air temperatures of 19 degrees and track temperatures between 23 and 30 degrees, on Tuesday the WorldSBK riders ran in slightly higher temperatures, while the asphalt was close to 50 degrees and this further highlighted wear problems over long runs.

For this reason, following a discussion between Dorna, FIM, Race Direction and Pirelli, it was decided that the races of both classes will take place with a mandatory pit stop to allow for a tyre change.

GIORGIO BARBIER - Motorcycle Racing Director

The safety of the riders must always be the priority

“We know this track very well, nevertheless every year it’s a whole other story because at Phillip Island the variables that can influence tyre behaviour are many and often unpredictable. This year the most critical element is represented by the new asphalt which has almost completely reset the references we had. I remind everyone that the tyres for this race were shipped from Europe at the end of November while the resurfacing of the circuit was completed only a few weeks ago. Therefore, in the absence of data on which to base ourselves, we thought it appropriate to rely on the racing solutions used successfully in the last two seasons. We have seen in the tests that the asphalt offers a lot of grip, to the advantage of the flying lap time, but on the other hand it is very aggressive with the tyres, especially at high temperatures, causing unusual peaks in tread compound temperature on the left side with consequent tyre degradation: we detected up to 160 degrees Celsius in pit lane which we estimate could reach operative peaks of more than 200 degrees. Considering this evidence, in agreement with Dorna, FIM and Race Direction, we have decided that for the races of both classes it will be mandatory to make a pit stop to change tyres. It was a difficult decision to take, also because, as always happens in these cases, some teams would have wanted to try racing over the full distance. However, Pirelli believes that the safety of the riders must be the absolute priority in such circumstances.”

KEEP AN EYE ON

• Tyre allocation: riders of both classes have at their disposal standard SC1 and SC2 tyres for the front and standard SC1 for the rear. In addition, WorldSBK riders can use two tyres in SC0 compound at the rear only for qualifying. In consideration of the new race format with pit stops, with respect to the standard allocation the use of two more sets of tyres is allowed.
• Race distance: WorldSBK Race 1 and Race 2 have been reduced from 22 to 20 laps while the Superpole Race is confirmed over a 10-lap race distance. The WorldSSP races will take place as originally scheduled over 18 laps.
• Pit-stop window: in both classes the riders will have a three-lap window in which to change tyres, with a fixed time in the pit lane. In WorldSBK the window will be between laps 9 and 11 while in WorldSSP between laps 8 and 10. It is mandatory for all riders to change the rear tyre while they will be able to decide whether or not to replace the front tyre also based on the tyres each rider has remaining.
• Weather: lower asphalt temperatures, below 30 degrees Celsius, can positively influence tyre degradation. On the contrary, higher temperatures, in line with those recorded in tests on Tuesday, would have a negative impact on the tyre life. Another typical factor at Phillip Island is the wind: if it were particularly strong it would disturb the riders' trajectories, making them slide more and increasing tyre wear.