Monday, August 31, 2009

Choosing Tyres in F1 Races

Teams can invest small fortunes (actually, make that very large fortunes) in developing race car technology, and drivers can be as brilliant as they like, but when it comes down to it, a car’s tyres are what actually keeps it moving on the track. So, as you might expect, development has crept into tyre design too! The teams are given a choice of two compounds of dry weather tyres from their supplier. The compound refers to the constituent mix of rubber and chemicals of the tyre. The compound choice will usually be between:
  • One that is more consistent and tougher-wearing
  • One that is made from a grippier chemical/rubber mix and therefore usually faster at its peak A team will prefer to be able to use the softer, initially grippier tyre but sometimes they are prevented from doing so if they cannot attune the car sufficiently so that the tyre’s wear rate is kept in check. In this case they will be forced to choose the harder compound.
The compound choice refers only to the dry weather tyres. The tyre company will supply wet weather tyres but there is no choice of compound for the teams to make.
The teams have to choose their dry weather compound before going out to qualify. They are stuck with that choice for the rest of the weekend, so a bit of forward planning is important. What compound they choose depends on the following:
  • The practice laps: The practices give the teams some indication of the wear rates and lap time capability of each tyre, enabling them to trade off one quality against the other in their calculations.
  • Info from the tyre manufacturers: The tyre manufacturers advise the teams after studying the practice data. This will include looking at the tyres’ lap time drop off, the difference in performance at its peak and just before the pit stop. At some circuits, there is virtually no drop-off –meaning that the tyre is still at a peak performance level when the fuel stop is made. At others, notably circuits like Suzuka in Japan that have lots of long duration turns, it is a significant factor.
  • The pit stop strategy: The choice of tyre compound is also linked to the pit stop strategy. If you go for a one-stop strategy, the extra fuel weight may destroy the softer, more delicate compound and force you to opt for the harder, slower, choice.
  • The driver’s skill: Much depends upon the sensitivity and control of the driver. If he can “nurse” the car through the early stages when the car’s weight is high, he may be able to make even the softer tyre “live” and therefore get the benefit of its extra grip as the fuel load comes down. You hardly ever know before the race what tyre and pit stop strategy a driver has chosen, as obviously this is information that could be used to advantage by his rivals and is therefore kept close to the team’s chest. You can always try asking if you get close enough, but they might lie.

Ross Brawn – strategy master

Recognised as the greatest pit lane strategist in Formula One, Ross Brawn helped Michael Schumacher to all five of his World Championships, first at Benetton and subsequently at Ferrari.
A gifted designer in his own right, Brawn’s greatest period of success began when he took up the role of Technical Director and left the design chief role at Benetton to Rory Byrne. Brawn became more of an overseer and organiser, albeit one with the technical insight to work hand-in-hand with Byrne. This came just at the time that Formula One re-introduced refuelling –which had previously been banned – thus opening out new avenues of competitive advantage. Brawn exploited this brilliantly, frequently making rival teams look inept with his dazzlingly quick mind.
He was aided in his operations by the searing speed of Schumacher and when the latter left Benetton for Ferrari, it took only another year before Brawn and Byrne followed him there. The three have been the architects of Ferrari’s renaissance, and in 2000 Schumacher became the first Ferrari driver in 21 years to lift the world crown.

Deciding F1 Strategy

The two principal tools of pre-determined strategy are tyre choice and pit stop timing. Deciding whether to use hard or soft tyres and whether to stop once (meaning your race will comprise two stints) or twice (meaning three stints) and at what intervals are influenced by a two really important considerations:
  • Where you are in the field: Over the past few seasons Grand Prix grids have tended to be split into three sections: the top three teams, the midfield, and the lower orders. Barring freak circumstances there’s no way a midfield or tail-end team is going to threaten for victory, no matter how brilliant their strategy. “The competition” is usually a reference to the cars in your own group. A team that has qualified in the middle of the midfield looks at what strategy could get it to the front of the midfield by the end of the race, rather than trying to take on Ferrari, Williams, or McLaren for victory. Strategies are usually decided from that perspective. Is that negative thinking on their part? No, just realism.
  • How fast your pit stops are: For reasons of pit lane safety, highly pressurised refuelling – whereby fuel flows into the tanks at a very fast rate under pressure – is limited. The refuelling equipment fills the tanks at the rate of 12 litres per second. Barring problems, refuelling – and not tyre changing, which can be accomplished in around three seconds – is what determines the length of a pit stop. The tyre guys could even have a cigarette while waiting for the refuellers. . . no, on second thought. . .