Competitive showing for Renault in Friday practices

The Renault F1 Team began its Hungarian Grand Prix weekend with a competitive showing in Friday’s free practice sessions, with Fernando Alonso finishing the day second on the timesheets and Giancarlo Fisichella third.

The cool track temperatures combined with the low-grip surface of the little-used Hungaroring circuit meant both drivers struggled for grip, and experienced tyre graining. However, the engineers were able to make progress on stabilising the car balance with a number of set-up changes, and will continue to work in this direction tomorrow to achieve a neutral, driveable in race conditions for what is always one of the most physically-demanding Grands Prix of the season.

Fernando Alonso "It was a good start to the weekend for me. The conditions were very low grip today and that meant the car balance was quite inconsistent, but we managed to do our normal programme, get a feel for the tyre performance and start making some set-up changes. I was having some problems with the rear end to begin with, but we managed to calm it down during the session and we will carry on working in that direction tomorrow. The times seem competitive, so I think we are on the right track."

Giancarlo Fisichella "I had a problem on my first lap when the traction control cut out on the exit of turn 7 and I half-spun. But we fixed it in the garage, and after that started the normal programme. It’s much colder than usual here in Hungary, and that means the conditions are very low grip indeed, coming from the track but also the tyres. The car was quite tricky to drive because of this, but we made some good changes and need to do some more overnight. It is going to be a difficult weekend because of the conditions, but we seem to be in reasonable shape."

FRIDAY FOCUS: TYRE MANAGEMENT IN HUNGARY

Tyre management has been a key theme of the 2006 world championship so far, and the unseasonally cool temperatures experience today and forecast for the rest of the weekend at the Hungaroring, have thrown a further spanner in the works for the teams.

Typically, the race weekend in Hungary is among the hottest of the year, with high temperatures and lots of direct sunshine heating the circuit to temperatures of around 50°C. Accordingly, tyres for the event were tested and selected in the balmy Mediterranean climes of Jerez and Paul Ricard. Today, however, track temperatures barely reached 25°C with significant cloud cover preventing any warming of the track surface. And although sunny spells are forecast on Saturday and Sunday, the temperature of the asphalt is still unlikely to exceed 35°C.

All this means every driver is likely to encounter, and have to manage, the same problem: tyre graining. One cause of this phenomenon can be tyres operating in cooler temperatures than they were designed for; another can be low circuit grip which means the tyres’ adhesion is not optimum. Both could be factors this weekend.

“Tyre selection is a complex process,” explains Renault’s Executive Director of Engineering Pat Symonds. “Fundamentally, tyre choice for an event is centred around selecting the compound. A tyre’s construction tends to be more universally applicable from circuit to circuit, but the compound must be chosen with knowledge of the energy the tyre must handle around an individual track. The total energy is a function of how much work the tyre must do around the lap – how many high-speed corners there are, for example, or traction events. But the temperature of the circuit is also a factor. If we encounter significantly lower temperatures than we had expected, as is the case this weekend, then the compound is forced to operate outside the conditions it was designed for.”

In cooler conditions, with the tyre running outside its operating window, it is unable to generate the correct adhesive properties with the track surface. As a result, graining ensues when the tyre slides: the rubber literally shears off the tyre and rolls up on its surface, usually at the front but sometimes also the rear. Front graining means increased understeer, and gradually disappears as the tyres wear (which ‘cleans up’ the ‘loose’ rubber from the tread); rear graining will leave the drivers fighting oversteer. The same phenomenon occurs on a ‘green’ track for similar reasons: with little rubber on the racing line, the correct adhesive properties cannot be generated and graining follows – as can often be seen on the Friday of a Grand Prix meeting before any significant running has been done.

So the key question may be, what can teams do to cope with the graining this weekend? “It is a problem we are familiar with from winter testing, which is usually conducted in much cooler temperatures,” continues Symonds. “One of the keys is getting the tyres up to operating temperature as quickly as possible, but there are also a number of other tricks you can employ – for example, running with older, worn tyres which are less susceptible to graining than a brand new set. Typically, we would expect problems with graining to reduce as the weekend goes on, but the cool temperatures and likelihood of overnight rain means we may well encounter this phenomenon during Sunday’s Grand Prix. It will be a case of coping with it as well as we can this weekend – and trying to minimise its impact on how we run our race.”