KART BIREL CHAMPIONS
20 YEARS LATER
In 2019, Marijn Kremers brought another world shifter victory to the Birel ART/TM Racing duo with the CRY 30 S10 chassis. A success that had been missing since 2000, when Gianluca Beggio won the Formula C world championship in Mariembourg with the CQ32 chassis (the Birel/TM victories from 2003 to 2005 took place in the World Cup, not in the World Championship). We compared the two karts to analyse the changes and developments that have taken place over the last 20 years.
CQ32 vs CRY30 S10
20 years is a long time in the world of sport, especially sports related to engines, where technological developments are very important. And yet, comparing the Birel ART winner of the FIA Karting World Championship 2019 to the CQ32, winner in 2000, there are also many common aspects. There are also differences due to changes in regulations. Every detail is worth analysing in depth.
Apart from aesthetics, the main difference between the 2019 and 2000 chassis is due to the factor that perhaps most influences the design: the tyres. The CQ32 of Gianluca Beggio mounted Bridgestone tyres fitted with a Kevlar casing and a very high-performance compound that allowed them to race at very low pressures (0.4 bar). To exploit them, the chassis essentially had two goals: to keep the kart glued to the ground and maximize traction.
The Bridgestones of the CRY30 S10 are very distant relatives of those tyres, due to regulations introduced by the federation to prevent the use of polluting materials and cap costs: the characteristics of the current tyres have led to the development of more balanced chassis.
Overall, the shape of a 20 year old chassis is not very different the current one. As for the Birel CQ32 the main difference is in the parabolic profile of the side stringers. These are welded to two other tubes near the tank, contrary to what happens with the CRY30 S10 chassis, whose side stringers consist of a single tube that goes from the C to the rear bumper attachment. Furthermore, the curves of the 2019 chassis have a more angular profile, which has undergone further adjustments in view of the world championship appointment. The diameters of the tubes also change: almost all of them are 32 mm for the CQ32 (with the exception of the two tubes to which the curved longitudinal stringers are welded and which connect the C of the spindles to the horizontal tube in front of the seat); all 30 mm for the CRY30 S10. Usually chassis for gearshift categories use 32 mm tubes, which offer more rigidity and resistance to stress. The use of Ø 30 mm meets the type of tyres used in KZ, aiming to exploit it in the best way.
To produce the CRY30 S10, Birel ART used cutting-edge robotic welding techniques that ensure precision and a uniform result for each body. On the contrary, the welds of the CQ32 were all manuallt realised. The difference in the production method is certainly important, but from a technical point of view the issue is debated: there are still currently manufacturers, includingn important ones, who continue to prefer manual welding carried out by specialised technicians (well assisted by last generation welders) to completely automated welding.
The regulations introduced for tyres have not only changed the performance, design and behaviour of the chassis but also the way in which a manufacturer designs them.
The continuity of races in the present day was absent at the end of the 1990s; in fact, the official teams only prepared the important event (World and/or European) by carrying out test sessions with the tyre manufacturers starting a couple of months beforehand. Being free to choose, the teams tried various tyres, even of various brands (Vega, Bridgestone and Dunlop), until they found the one considered the best for the track and the period of the year in which a race was scheduled. Drivers of the same team could race with different tyres and customisation was really extreme. If it was believed that the combination of tyres and chassis could still be improved, there would be further adjustments to the dimensions of the body.
The current regulations have totally changed things, imposing the same tyre for all and approvals for tyres with a duration of 3 years. In the rpesent day there is a need to be competitive in all conditions and for quite a few more races a year, so it is right to use the word development when talking about the design of a kart: the teams continuously collect data; the engineers evolve projects in small steps, trying to make the chassis effective for all driving styles; testers are on the track more than twice a week throughout the season.
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