Pirelli wants to reduce marbles in 2014

Problem that went relatively unnoticed in 2013, due to the multiplication of controversies around the wear and durability of Pirelli P-Zero tires, the large presence of rubber marbles – called marbles in English – which escape from the tires off-line is a concern for both the drivers and the Italian manufacturer.

Indeed, these pieces of rubber make any maneuver that forces a driver to go off the normal trajectory delicate, both in braking and in maintaining tire grip and the sensation of vibration that prevents pushing the car to its maximum under good conditions once these pieces stick to the wheels. A situation that Pirelli takes very seriously: « The drivers have made comments about this and we can understand it. It’s something we are trying to address, » explained Paul Hembery, director of motorsport at Pirelli, to our British colleagues at Autosport.

« Once in the season, there’s really not much you can do about it. » A loaded statement at a time when the absence of private tests does not allow the tire supplier to correct the intrinsic flaws of its product. This state of affairs has led to many problems encountered during the season, such as tire inconsistency or their premature delamination.

The issue of the marbles seems nonetheless confined to the softer compounds: « We know it’s clearly related to the casing; it’s simply the tire degradation in certain cases, certainly the super softs and, to a lesser extent, the softs don’t have the strength we are looking for. You can see some races where we have almost no marbles when using hard and medium tires, or some less abrasive surfaces. So we are working to try to improve that. The general desire of the drivers is “reduce the marbles ».

The work of Pirelli is primarily focused on understanding the phenomenon: « For now, we are doing a lot of work to measure and understand where the differences are between the different compounds; we wanted to try to improve things like the resistance to compound detachment, which has a direct impact on the marbles. » Especially since in 2014, there will be no shortage of difficulties: « With the increase in wheelspin, there is a chance of creating even more marbles than we have today, so we need to improve the mechanical strength of the compounds. »

Research that is therefore not without risks if an imbalance occurs: « If you go too far, you end up with more sliding because you have no grip. Finding the balance will be challenging because we do not know the real impact of the aero when we start driving. There is also the risk that there will be significant differences between teams. »