The tyres chosen by Pirelli to race at the University of motorcycling for the third round of the eni FIM World Superbike Championship
The new 17 inch Pirelli Diablo Superbike tyres in SC1 and SC2 compound are called on to tackle the weekend on the Dutch track of Assen after excellent results already achieved in the first two rounds of the season
The new intermediate Diablo Wet tyre, also due to the new “Flag to Flag” rule, could play a fundamental role in the event of unpredictable weather conditions
Pirelli is ready to take on the third round of the eni FIM World Superbike Championship which will be held this weekend at the Dutch circuit of Assen, also known as the University of motorcycling because of its characteristics. In particular, the new 17 inch Pirelli Diablo Superbike tyres will be available for both the front and rear in standard SC1 and SC2 compound as well as with alternative development solutions.
In the event of varying weather conditions with rain showers, the Assen round could also see the début of the new intermediate tyre designed by Pirelli, the Diablo Wet.
In fact, Diablo Wet could be the solution that the teams and riders bank on if the races start in wet conditions due to recent or dwindling rain and finish on a completely dry track, but also if the conditions are reversed, with riders starting on a dry track and the weather shifting to rain showers during the race.
The new “Flag to Flag” rule introduced this year which allows the riders to make a pit stop to change the tyres in order to avoid stopping the race in the event of rain, while on one hand allows the race to continue, on the other it means that riders will lose a lot of time to stop and change tyres. In some cases the Diablo Wet could prove to be an essential part of strategy because it would allow the riders to avoid stopping and losing precious minutes.
The TT Circuit Assen was designed specifically for motorcycles. It has always been considered one of the most difficult in the championship, even earning the nickname “University of motorcycling” due to its extremely fast average speeds. Despite the recent modifications which have partially changed its fame, the circuit still puts bike, rider and tyres to a hard test. The circuit was built in 1925 and for 30 years hosted road races through the towns around Assen. At the time the track was about 28 km long. The modern circuit was not built until 1955, no longer open to daily traffic, and the total length was reduced to 7,705 m. The most recent significant change was made in 2006, entirely eliminating the first part of the circuit, a very fast and particular section for a modern track, which reduced the length by almost 1,500 metres. In its place new stands were built, higher capacity than the previous ones, overlooking the new group of first slow turns. Today, after the many changes made over the years, the track is 4,552 metres long with the longest straight stretch measuring 970 metres, 11 left hand turns and 6 right-handers.
TT Circuit Assen from a tyre point of view:
The Assen track is very interesting because the tyres, although not very stressed from a thermal point of view, must be capable of providing the rider with great precision and a lot of directional stability. During the springtime, which is when the Dutch round is schedules, the Assen circuit is generally subjected to weather conditions which are often unpredictable as well as rather cold temperatures.
The first right hand turn deserves particular attention, which is very long, taking about 15 seconds to get through it. The rear and front tyres must be perfectly balanced in order to maintain a perfect line at an average speed that exceeds 100 kph. The most important point, however, is the following left hairpin, which has a curvature radius of less than 20 metres. The rider is forced to change the lean angle of the bike at a speed of 70 degrees per second, so from a leaning position of about 40° on the cold left side of the tyres, he has to brake hard, come out of the turn at maximum speed (guaranteed by the front tyre) and then accelerate almost from a standstill taking maximum advantage of the grip provided by the rear tyre. This sudden change from an extremely long turn to a high and constant speed to a sudden hairpin in the opposite direction, characterised by a braking section from a leaned position, is very demanding on both tyre and rider.
After this there is an extremely fast flip-flop. The rider has to navigate the double turn at a high speed of about 150 kph, first to the left, and then about 110 kph on the left-hander, but above all he has to move quickly from a maximum left hand lean to maximum right hand lean, changing angle at an astonishing speed of about 90° per second. The rear and front tyres must reach an extremely demanding balance in order to allow the rider to get through the chicane as quickly as possible.
After this the rider takes on a situation which is reversed with respect to the first turn. First there is a tight turn to the left with a curvature radius of about 50 metres, followed by a wide right-hander where the bike maintains a 50° lean angle for about 8 seconds. The rear tyre must guarantee the best possible acceleration coming out of the turn, allowing the rider to speed up from 90 to 150 kph as quickly as possible. In fact, the riders who are able to open up the throttle first will gain a decisive advantage.
The Assen allure lies in this series of long and constant speed turns, slow U-shaped turns with braking and sudden acceleration, quick chicanes and long turns with strong acceleration coming out with the bike still leaned over.
Made up of a very high bituminous percentage, the asphalt at Assen represents a strong correlation between how aggressive the track is and the air temperature. This means that with low temperatures the rear solutions can suffer from problems with tearing (by now well known as cold tearing), particularly in the event of soft solutions (and therefore less resistant) and when the track is poorly rubberised, typically during the Friday sessions.
Therefore all the softer versions could be risky for this time of year and this is why high performance over a few laps is usually foregone in order to guarantee the best protection against tearing for the long run in view of the races. In fact, the cold tearing effect, once it begins, prevents the tyre from functioning properly, drastically damaging its level of grip and handling.
Therefore the rear solutions available will go from the SC1, with less protection available but higher performance, to SC2, greater protection available (required only for critical situations). The two prototype solutions (R1688 and R829) available for Superbike are also included in this range.
On the other hand, where the front tyres are concerned there are no particularly critical issues. Generally, since Assen is quite a ridden track without any violent braking sections, the front tyre choice tends more toward the higher performance SC1. In fact, the new front Diablo Superbike S41 falls within the SC1 area in order to increase the riders’ options.
TT Circuit Assen from a technical point of view:
“Although the Dutch track has been a bit altered in recent years, losing a few of the fast chicanes, it is still a track with very aggressive asphalt but with good water drainage, capable of drying off quickly in the event of rain, because it is in an area which is traditionally exposed to the wind” said Giorgio Barbier, Pirelli Moto Racing Director “Even more than Phillip Island, Assen is an extremely varied track where dry sections can sometimes alternate with damp or wet sections, so it is a track where the right tyre choice made by the teams could prove to be essential for a win. In the event of damp conditions or light rain, the new intermediate tyre could be very useful both to allow riders to avoid losing time for tyre changes and because, if there are alternating dry and wet areas on the track the pure rain tyre may not provide optimum performance.”
Pirelli solutions for the Superbike and Supersport classes:
For the Superbike and Supersport class es Pirelli will be providing various solutions for the riders to choose from, all in SC1 and SC2 compound both from the front and rear, including development solutions as an alternative to the standard tyres. Pirelli will take a total of 4848 tyres to Assen and each Superbike rider will have 34 front and 40 rear available, while the Supersport riders will have 25 front and 29 rear tyres available, taking the regulations into consideration which state that Superbike riders may use a maximum of 9 front and 13 rear tyres up to warm-up, whereas Supersport riders have a maximum of 9 front and 11 rear.
For the Superbike class Pirelli will take three slick solutions for dry on the front and four 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 solutions (4 available for the front and for the rear) as well as wet solutions (8 for both the front and the rear).
On the front the slicks that Pirelli has chosen are the same ones which were used on the Spanish Motorland Aragón circuit in the last round. There will be an SC1 solution (R426) in a soft blend and the SC2 standard solution (R982) in medium blend, joined by the S41 development solution in a soft blend as an alternative to the standard SC1 (R426) intended to reduce cold tearing and to provide greater mechanical stability, a good compromise between the SC2 for solidity and the SC1 in terms of grip.
On the other hand, the rear selection will include a range of four options. These will include the standard SC1 (R828) in medium compound which were already seen at Phillip Island and which were used by all the riders on the starting grid at Motorland Aragón, as well as the standard SC2 (R832) in hard blend, capable of providing greater resistance even in the event of low temperatures. In addition to the standard SC1 and SC2 solutions, the R829 will be present, a development solution that met the track for the first time at Motorland Aragón and which, in terms of compound hardness, fall halfway between the standard SC1 and SC2, as well as the R1688, a new SC1 compound development solution capable of ensuring better grip than the R829 and more sturdiness than the R828.
As for Supersport, for dry on the front the riders will be able to choose from the two standard solutions, the SC1 soft compound (P1177) and the SC2 medium (R1031), already used at Motorland Aragón.
On the rear the riders will have the standard SC1 medium compound (R303) and the R1610 which has a blend designed for grip similar to the SC1 but with cold tearing resistance typical of an SC2. On the other hand, this will be the début round for the standard SC2, the R1136, a valid option in case of very low temperatures.
The 2012 Pirelli statistics for TT Circuit Assen:
• Total number of tyres Pirelli brought: 4806
• Number of solutions (dry, intermediate, wet and qualifier only for rear) for the Superbike class: 5 front and 7 rear
• Number of solutions for the Supersport class (dry, intermediate and wet): 4 front and 6 rear
Number of tyres available for each Superbike rider: 29 front and 39 rear
• Number of tyres available for each Supersport rider: 29 front and 30 rear
• Superbike Best Lap Awards won by Sylvain Guintoli (Team Effenbert Liberty Racing) in 1’57.793 (Race 1, 9th lap) and Carlos Checa (Althea Racing) in 1’38.092 (Race 2, 16th lap)
• Supersport Best Lap Awards won by: Lorenzo Lanzi (Prorace) in 1’59.828 (17th lap)
• Temperature in Race 1: air 9° C, wet asphalt 7° C
• Temperature in Race 2: air 14° C, wet asphalt 12° C
• Maximum race speed reached by Pirelli tyres: 286,8 km/h, Marco Melandri (BMW Motorrad Motorsport) in Race 2 on the 7th lap