On the 15th anniversary of one of F1’s most infamous races, Matchday FM asked race engineer Antony Stott what made this race memorable for all the wrong reasons...
June 19th 2005 was one of the most controversial Formula 1 races in modern history.
20 cars lined up on the grid for the formation lap, but then one by one, several cars retired to the pits until only 6 cars remained for the start of the race. But why did this happen? One word - tyres!
In order to understand what happened, first we need to consider a few things:
The race was being held at the Indianapolis Motor Speedway, made up of part oval - part ‘twisty infield’ section.
Back in 2005, there were two tyre manufacturers for teams to choose from; Michelin and Bridgestone. Everyone except Ferrari, Jordan and Minardi chose to run Michelin.
That season also saw a new regulation implemented that stated a driver had to use one set of tyres during qualifying and the race, this removed the possibility of mid-race tyre changes. It was this rule that had already caused problems for Kimi Raikkonen in the German GP, as a badly worn tyre had collapsed, ripping his suspension apart on the last lap.
What Happened?
It all started in FP2 when Ralf Schumacher’s rear left tyre failed on the full throttle banked corner sending him into the wall at 175 MPH, retiring Ralf for the weekend and promoting Ricardo Zonta to the hot seat. He then also suffered tyre failure in that same session. This sent alarm bells ringing throughout Michelin.
They set to work investigating the problem even shipping in a new batch of replacement tyres. However these were a similar spec and suffered the same problem. Michelin could not guarantee their tyres would last more than 10 laps.
Why?
Being an oval track, Indianapolis Motor Speedway had a long full throttle banked right hand turn. This type of corner poses a unique issue for tyre manufacturers when considering the loads applied to the tyre.
As a car travels around a flat corner, let’s say a right, the 'grippy' tarmac of the track resists and pulls the contact patch to the left. This stretches the tyre wall along the outside edge, repeated stretching of the tyre weakens it until the rubber tears and eventually leads to failure.
When travelling around a banked corner, the same forces apply. However the weight of the car is not going straight into the track, but due to the angle of the track, a component of this weight is adding to the force pulling against the tyre. This is why cars travel so much faster through banked corners, this causes more strain on the tyre.
Michelin, like the other manufacturers, knew the challenges the track layout posed. But this wasn’t the sole cause of their tyre woes.
The other contributing factor was the track had recently been re-surfaced and diamond ground smooth, this leaves a series of grooves along the direction of the track.
This means that when turning, the way the track resists tyre movement is more acute, grabbing the rubber with more intensity.
Michelin had failed to anticipate this surface behaviour through both testing and simulation data. Meaning they were massively under-prepared. Bridgestone on the other hand, had ample amounts of data through their American Firestone brand. As it stood only teams running Bridgestone tyres would be able to race.
An effort was made to run the race as planned, with several options suggested.
The FIA suggested that the teams running Michelin tyres just drive slower though turn 13. This was rejected due to the danger of cars running at different speeds at a high speed corner.
Bosses then said the rules would be altered for one race only, allowing teams to change tyres every few laps with penalties. This was rejected as shipping the volume of tyres required in the time frame would be a logistical nightmare.
There was even a suggestion of adding in a temporary chicane on turn 13, with the teams getting to approach it differently, depending on their tyres. But the FIA said no changes to circuits could be made as they would need to be inspected and tested first.
This was pretty much game over for the Michelin teams although the negotiations continued up to the start of the race. Drivers could be heard on the formation lap pleading over the radio to be allowed to race, but they had to withdraw. And so only the three teams running Bridgestone tyres were allowed to race.
Max Mosley was quoted after the race saying:
“They could have used the pit lane on each lap, the pit lane is part of the circuit. This would have avoided turn 13 altogether. It’s difficult to understand why none of them did this”.
But surely having 14 cars going through the pit lane every lap, with some pitting and some not, this would be more dangerous than having a temporary chicane on T13?
The Michelin teams were charged by the FIA for several charges from failing to ensure adequate tyre availability, to damaging the image of the sport. But these were ultimately dropped.
The one set of tyres rule was scrapped at the end of the 2005 season and within a couple of years both the Indianapolis circuit and Michelin were no longer a part of F1. Suggesting that both the FIA and F1 learned their lesson from one of the sports most infamous races.
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