2013 World Superbike Tire Analysis
Pirelli is ready to take to the track for the first round of the eni FIM World Superbike Championship season with the new 17 inch Diablo Superbike tires for dry, Diablo Wet for intermediate and Diablo Rain for wet.
Pirelli has been present at the factory derivative races since the Championship’s inception in the late 1980s, but with the season which is about to start, this will be 10 consecutive years of presence for the Milanese manufacturer as sole tire supplier for all the classes that are part of the World Superbike Championship.
This is a unique achievement that earns the brand with the long “P” the record for the longest running control tire supplier, and consequently the most successful, in the history of motorcycle sports on an international level.
The first round of 2013 also marks an era-making milestone in the history of two-wheel racing because of the switch from 16.5″ tires to the new 17″ tires. Over the winter and during the season last year, Pirelli engineers worked tirelessly, completely redesigning the new tires which now have new profiles and sides, as well as a larger tread contact surface.
These tires ensure a reduction in movement and improved stability and handling in turns, as well as the ability to maintain performance throughout the race. The compound range was also redesigned from scratch based on the new structure of the 17 inch tires and now the new blends are softer, more versatile and higher performance.
As usual, the first round of the eni FIM World Superbike Championship season will take place at the spectacular Phillip Island circuit, located in Victoria 150 kilometres south of Melbourne. It is to be held from the 22nd to the 24th of February but all the teams will already be on the track Monday the 18th and Tuesday the 19th for the official season launch tests.
Actually some teams already conducted some pre-testing sessions on Thursday the 14th and Friday the 15th but Pirelli did not participate in order to remain neutral and not favour anyone since these were private tests which did not involve all the teams. Precisely to prevent the teams who participated in the pre-tests from having any advantage over those who did not take part, Pirelli decided to provide them only with standard tires in the range.
On the other hand, the entire line of tyres scheduled for Phillip Island will obviously be available for the entire weekend during the official tests where all the teams will participate, complete with development solutions designed specifically for the Australian track .
The Phillip Island track, built in 1956, has an exciting layout with a series of fast and long turns broken up by only two fast little turns where we usually see a lot of overtaking. The only straight line of any significant length is a downhill stretch in front of pit lane that reaches some of the highest top speeds of any circuit on the calendar. Photographers from all over the world love the various sections by the sea which are quite characteristic and breathtaking.
During the month of December 2012 the track underwent an extensive “facelift” which involved the first resurfacing of the track in 14 years. In fact, the previous layer of asphalt dated back to 1998. The job required 5 thousand tons of asphalt poured in two days to renew the 4448 meters of track and make the Australian circuit the smoothest and one of the fastest in the world. This makeover operation will no doubt play a key role this year in terms of the tyres which will have to take on new asphalt (which therefore inflicts more wear) which has never before been raced on.
Phillip Island from a tire point of view:
Phillip Island has always been one of the most demanding tracks on the Superbike calendar for tires, which are subjected to strong and constant thermal-mechanical stress, especially on the left side. In fact, compared to the Monza track, where the tire only has thermal work to do and only the central part is subjected to stress because of the long straight stretches that overheat the tyre, at Phillip Island overheating occurs in an area of the tire, but it is at maximum lean angle at the same time and that generates forces stemming from various origins with torsion and very strong oblique work.
So the particular characteristic of the Phillip Island track is that it simultaneously generates a mechanical stress and a thermal stress to which the tires are constantly subjected.
A peculiarity of the Philip Island track is the famous left hand turn, the longest parabolic of any other turn on the circuits in the eni FIM World Superbike Championship. Besides being the longest, this turn also has a medium-side radius which allows the riders to navigate it at full throttle, with a fixed lean angle for a long period of time.
In these conditions the tire is forced to work for quite a while with mechanical stress focused on a small strip of tread and, precisely in that area of continuous use, there is a rapid temperature increase.
A rise in local temperature like this causes a loss of grip on the asphalt which, in turn, due to the rubbing of the tread against the road surface, causes a further increase in temperature due to friction and a large amount of material is removed.
Therefore there is an exponential and uncontrolled rise in temperature capable of generating a thermal breakdown of the compound (commonly known as blistering). This can be limited only by the rider’s skill and a meticulous fine tuning of the electronics, but this is complex because it would need to be calibrated for each individual turn.
This phenomenon occurs on any asphalt, no matter what type. It can certainly determine how quickly the heating occurs, but the end result is unpredictable in any case. For example, if very smooth asphalt like that seen in past years can increase the chance of losing traction, forcing the riders to constantly struggle to regain grip, asphalt with good grip (like we will probably see this year) limits sliding, but on the other hand it will be much more aggressive and at the same amount of slide it will have a much higher abrasion and heating tenor.
The track also has various fast turns which have an intense impact on the front. Until now wear on the front had never been an issue because of the completely smooth asphalt, but now, with the new surface (certainly much rougher than before) this aspect could play a determining role.
Obviously Pirelli engineers have worked toward preventing these problems by designing development solutions which will be able to handle the critical issues on the Phillip Island circuit.
Phillip Island from a technical point of view:
“The Phillip Island circuit has always been one of the most spectacular and exciting ones on the calendar, but at the same time it is also one of the most difficult and demanding for any tyre manufacturer who has to race here, precisely because of the particular layout of the track that stresses the tires especially on the left side” said Giorgio Barbier, Pirelli Moto Racing Director “Furthermore, specifically in our case, the period when the races are held coincides with the Australian summer, so temperatures are higher and this definitely makes an already difficult track even more trying on tyres which are forced to work at extremely high temperatures.
Besides that, this year a further unknown is added to the equation: the new asphalt that no one, including Pirelli, has been able to test yet. If, on one hand, because it is new asphalt it will ensure a surface that can provide excellent grip, on the other hand it will be harder and more aggressive on the tyres.
Due to the fast entrances into turns, particularly in the first part of the track, in addition to the stress on the rear tyres, this year the front tyres will be put to the test as well. Like every year, Pirelli obviously had to ship the tires to Australia well in advance, even before the resurfacing work was finished, so in order to avoid the thermal-dynamic problems typical of this track, we designed development solutions with different structures and compounds (although they are all the same size) which guarantee that the riders will be able to finish the races. For Pirelli the Australian track will be a challenge because the new 17 inch tyres will make their début and this definitely makes the Australian round a very important weekend”.
Pirelli solutions for the Superbike and Supersport classes:
Since Phillip Island is a unique circuit for the reasons stated above, in order to take on the particular characteristics of the Australian track and place the riders in the best possible racing conditions, Pirelli has designed various development solutions which come alongside or completely replace those in the range and which can be widely used throughout the other European rounds on the calendar as well. At Phillip Island, since this is a round outside of Europe, only the Superbike and Supersport riders will participate, for a total of 56 riders and 3580 tires brought by Pirelli.
For the Superbike class, which has 21 riders on the starting grid (19 permanent and 2 wild cards), Pirelli will provide four slick solutions for dry on the front and as many for the rear. These are joined by the rear qualifier that riders will be able to use in the three Superpole sessions on Saturday and the intermediate and wet solutions available for both the front and the rear.
The slicks chosen by Pirelli on the front are an SC1 solution in a soft compound range and three SC2 solutions in medium compound, one of which is in the standard range and two more sturdy models which were custom designed to handle the new Australian asphalt.
For the rear Pirelli will provide the riders with a choice of four development solutions: two SC1 medium compound and two SC2 hard compound.
Of the two SC2 solutions, one (the R1300) is a solution midway between the SC1 tyres and the SC2 R1301. It provides better wear resistance than the SC1 solutions and more grip than the other SC2. All of the rear solutions were developed using particular internal materials with the goal of keeping operating temperatures low in order to prevent overheating in the extreme areas of the left side tread.
In fact, overheating on the left side which can cause blistering is not a simple fix using a harder compound like one might think, but rather it is resolved by cooling the tyre from the inside with the use of specific structural materials. At the same time a blend which is too soft like the SC0 would wear too quickly on the new Australian asphalt which is particularly abrasive, and this is why it was not brought to this round.
As for Supersport, which will have 35 riders lined up on the grid (33 permanent and 2 wild cards), the basic philosophy Pirelli adopted was the same as that used for the Superbike selections. The riders will be able to choose from two dry solutions, one in a soft SC1 compound and the other in a medium SC2 compound for the front and three solutions for the rear – one medium SC1 and two SC2 solutions in a harder blend, one of which (the R1287) is midway between the SC1 and the harder SC2 and it can guarantee better mechanical resistance than the SC1 and better grip than the sturdier SC2.
The 2011 Pirelli statistics for Phillip Island:
- Total number of tires Pirelli brought: 3874
- Number of solutions (dry, intermediate and wet) for the Superbike class: 5 front and 6 rear
- Number of solutions for the Supersport class (dry, intermediate and wet): 5 front and 5 rear
- Number of tires available for each Superbike rider: 33 front and 34 rear
- Number of tires available for each Supersport rider: 31 front and 29 rear
- Superbike Best Lap Awards won by: Max Biaggi (Aprilia Racing Team) in 1′ 31.785 (Race 1, 4th lap) and Carlos Checa (Althea Racing) in 1’ 32.846 (Race 2, 6th lap)
- Supersport Best Lap Awards won by: Fabien Foret (Kawasaki Intermoto Step) in 1’ 35.274 (2nd lap)
- Temperature in Race 1: air 31° C, asphalt 42° C
- Temperature in Race 2: air 34° C, asphalt 54° C
- Maximum race speed reached by Pirelli tires: 324.6 km/h, Max Biaggi in Race 1, 5th lap