How is a motorcycle tyre tested? When feel becomes method

Today we are talking about tyres, an element of fundamental importance, the point of contact between the motorbike and the ground, to which we entrust the pleasure of riding, safety and performance. In recent years it has been the subject of incredible development, thanks to a process that starts in the R&D department and is completed with the definitive real-world test: riding. At the end of the process, the person — the tester — is fundamental to the development and fine-tuning of a tyre.

What does the work of a tester consist of? What are the checks that must be carried out? What requirements must they possess? Let us start from here.

The first important thing, which can open the door to this remarkable profession, is that you do not need to be a world champion. However, a good basic motorcycling background, curiosity, consistency and a great passion are a must.

The most important quality of a tester is riding sensitivity. There are those who possess it as an innate talent, and those who must build it through experience, test after test. In both cases, time and humility are always required, because the characteristics to be analysed are complex, and not always easy to understand. Sometimes it is necessary to revisit a judgement, call it into question and start again from scratch. It is not a defeat; it is part of the method. This is why consistency is required.

A tester must have the disposition of a researcher. They must be curious, want to understand and delve into the details. They must always ask themselves: why does this happen? How much margin is there? How can it be improved? They must not stop at the superficial sensation, but must seek the cause of a behaviour, and for this it is necessary to engage in dialogue with colleagues in R&D. It is necessary to work from the project, study its application in the field, that is, in riding, and if necessary start again from scratch.

It often happens that specific aspects need to be investigated in greater depth, requiring a series of further checks, and for this a great deal of passion is needed. And a solid basic grounding.

At Pirelli, the training of testers, both for two wheels and four wheels, is defined by the performance evaluation manual. It starts from the definition of the parameters of a tyre that will need to be assessed. Now let us go into the technical detail by looking at the main ones. We might ask ourselves: would I be capable of evaluating them?

• Feel of tyre contact with the ground. It is an essential attribute, because it enables the rider to perceive the work of the tyre on its contact patch and to assess grip. In addition to this, it transmits the micro-movements of the tread, the minimal adaptations to the asphalt, elements that are indispensable for riding in harmony with the motorbike, as a guarantee of safety and riding pleasure.

• Predictability of behaviour. The tyre must return information about behaviour in a predictable manner, never causing anxiety, so that the rider can understand what is happening at that moment and has time to react to correct the motorbike's responses and avoid the problem.

• Agility. In summary, it is the speed and ease with which the motorbike changes direction. It is an interesting parameter, because it must be chosen: a highly agile tyre can make the motorbike extremely quick in tight sections, but more nervous at speed; a less agile tyre can make the motorbike heavier to ride but, on the other hand, give a feeling of great support and stability. The right balance must be found, and the choice depends on the project and the company philosophy.

• Warm-up time. It is the speed with which a tyre reaches the correct operating temperature, the state that guarantees the maximum quality of its characteristics, grip, feeling, precision and predictability. It is a fundamental characteristic for a road rider, who generally sets off on a cold tyre and wants immediate confidence, covers few kilometres, uses the motorbike in variable weather conditions and often at a relaxed pace.

• Balanced response front and rear. It is the balance of behaviour between the front and rear tyre: the front end and rear end must communicate in a synchronised manner (the two tyres "speak the same language"). The harmony, balance and consistency of reactions must be assessed. The objective is to arrive at a pairing that allows the motorbike to move as a single body, for everything to happen with fluidity, for the line to come naturally and for there to be no sudden reactions.

After the theory, the most intense phase begins: working alongside a senior tester. It is long and complex; indeed, one works together for a couple of years. You ride on track, on the road, you compare assessments and constantly verify the alignment between what the trainee states and the instructor's impressions. It is a delicate process, the result of continuous dialogue.

"The apprenticeship is a period I recall with great emotion," recounts Vincenzo Bonaccorsi, head of testing and technical relations at Pirelli. "You live with a certain amount of anxiety because you always feel under scrutiny. You are there waiting for the senior test rider to come back into the pits and when he arrives you hang on his every word, listening in silence to the verdict. You immediately understand whether you have hit the mark or not, there is no need to go into great detail, two words are enough.

The difference between a smile and a headache. Sometimes I would come home tired, sometimes disappointed. But it was a good kind of tiredness. The kind that toughens you. The kind that teaches you to trust your feelings, and also to verify them. And it is the part that shaped me the most."

This overview gives an idea of how interesting and complex the tester's job is. Do you think you are the right person for it? Then start to "feel" your motorbike, listen to it in every situation you face every day, and focus on learning its reactions. This is generally not done — one rides instinctively without thinking about what is happening in the overall rider-machine unit. But it is the first step towards understanding the behaviour of a motorbike.

Then, when changing tyres, analyse all the new elements involved, whether you are changing brand, changing model, or moving from a worn tyre to a new one: you will see how many differences there are!