Downforce, tyres, turn 13 and the show...Toyota Senior General Manager Chassis Pascal Vasselon talks of the demands of the US Grand Prix at Indianapolis. Indy is the only place with banking. What does that mean for car set-up?
"It has a lot of consequences. Indy is so
special that it led to the amazing tyre story last year that I am sure everyone would prefer to forget. That highlighted just how specific Indy is. It's a circuit which leads to almost impossible compromises for two aspects – tyres and aerodynamics. For the banking you would like to have a Monza low-downforce configuration because you are at full throttle for 22-23 seconds. And then, as soon as you enter the infield you would like to be in Monaco high-downforce trim. You have to arrive at a compromise according to the other elements of the package."
Such as tyres?
"For tyres it's tricky as well because on the one hand you have the very high rear tyre wear. When the cars go onto the banking you have the compression and also the asphalt is very rough. So the high wear means that we can't go very soft on compound. But then, when you enter the infield, it's very slow and you need a lot of grip, especially because you are tempted to run low downforce. These two elements are really conflicting."
Can you explain why you can run dry tyres on a damp track at Indy?
"The wet race situation is again special because of the banking.
You can take the long corner onto the straight flat-out because cars are not tyre grip limited thanks to the banking. Indianapolis is a place where you can sometimes use an intermediate when it rains and a dry tyre when it's damp, simply because you warm up the compound with the banking. You are flat out and you generate heat without being at the limit of the tyre. And then you have that heat which translates into grip for the infield. So it's a place where we always use one step more towards the dry."
Can you explain the trade-off between tyre performance in Turn 13 and on the straight?
"To make the tyre life easier we adjust the camber precisely and you have an operating window you must stay within. You cannot have too much camber because the straight is very long and you can overheat the inside shoulder of the tyre. But you cannot have too little camber either because, if you remember last year, the tyre issue was on the outside shoulder. The banking loads up the outside shoulder a lot. So you have a narrow window and you have to balance the outside shoulder against overheating the inside shoulder on the straight, which happens at Monza. It is quite a tricky compromise."
Will the tyre companies be more conservative this time?
"Both tyre companies have taken the issue very seriously. What happened last year was quite unexpected because it was not the first race there. I think both tyre companies will be able to avoid further problems."
Why is it so difficult for tyre companies to simulate Indy conditions?
"The banking is very special because it's not a straight line. To prepare a Monza tyre, for example, is relatively easy because you can simulate on test rigs simple straight line conditions. But at Indy you have a combination of high speed, high load and some lateral load, and this is tricky to reproduce on a test rig. It's not extremely severe either in a straight-line or cornering, it's the combination that adds up to challenging circumstances."
Was the '05 problem down to having to do the whole race on one set of tyres?
"Yes and no. That influenced tyre design but the tyre issues were happening before 10 laps, so we cannot say that it was related to the regulation."
What are your personal thoughts on Indianapolis?
"It's good if you go to a steakhouse. Big steaks! But seriously, it is such a famous place. You have F1, Le Mans and Indianapolis. It has a lot of history and legend. I remember the first time I went, in 2000, the crowd was unbelievable. And I remember the very first car that went out, a Jordan. People had been talking and shouting and then suddenly it all stopped when they heard the sound of the V10. It was so strange for them. They were used to V8s at low revs and this was a very different sound. That always sticks in my memory. It is a great place and the stadium atmosphere is fantastic and something we don't have in Europe. Still, my feeling is that for the American people there are not enough crashes in F1. It's not like NASCAR!"
Last year apart, does F1 put on a good enough show for the Americans?
"It is different for them and probably a bit more engineering led. Drivers are massively important but there is also a lot of emphasis on strategy and so forth. In the US races give more scope for pure racing spectacle on the track and less room for behind the scene technology. If a car is dominating too much you have a pace car and so it's organised so that you don't build up big differences between cars and drivers. So possibly for US fans we have a bit too much emphasis on engineering which if you get it right builds a gap to the others and that s it till the end of the race."
What happened last year as you tried to leave the circuit?
"Nothing. I was in Cologne, still on gardening leave before joining Toyota from Michelin! It was the last race I did not attend. I can understand the fans' disappointment and I hope we put on an exciting spectacle for them this time."
Source Toyota
