Misplaced Bar Code Cause of Wurz Crash

Wurz was lucky to escape injury when he crashed at more than 180mph on the exit of the Virage de la Verrerie on the final day of the test. Initial suspicion as to the cause of the accident focused on a tyre failure, and Michelin duly flew the suspect rear tyres to their Clermont-Ferrand base for investigation over the weekend.

Initial analysis of the tyres by Michelin ruled out a problem with the design or construction of the tyres, which was of a type that had already been evaluated extensively.

Michelin's motorsport director Pierre Dupasquier told Autosport-Atlas: "That construction has been used before at Paul Ricard, we did not test any new construction and it is the same tyre that we used in Barcelona - so we had absolutely no suspicion about the tyre integrity."

Further investigation of the tyres did reveal, however, that the tyre failure was most likely caused by it having been fitted the wrong way around on the wheel rim. With Formula One tyres specifically designed for one direction of rotation, the wrongly fitted tyre was unable to cope with the kind of stresses tyres are normally put through and, with teams focusing on high-speed running that day, duly failed after being put through the quick first chicane at the track

Autosport-Atlas has learned that the fitting error had come about because a Michelin tyre fitter had got confused about which way to put the tyre on the wheel, due to the presence of an incorrectly placed bar code.

Michelin had been working in co-operation with the FIA on the placement of an extra bar code for the tyres, which was supposed to be fitted alongside the usual Michelin bar code and Michelin reference number - which are always on the outside edge of the tyre.

But one of the new FIA bar codes had been placed incorrectly by Michelin on the inside edge of the tyre, alongside the Michelin test number reference. After this was mistaken for Michelin's usual bar code, a fitter incorrectly believed that this was the outside edge of the tyre - therefore fitting the tyre the wrong way.

Dupasquier confirmed that the company believed that the bar code error set off the chain of events that ultimately led to the tyre failure.

"The fitters did not pay attention to the fact that there were two bar codes and mounted the tyres in a non-appropriate way," he explained. "We know that could have led to minimising the capacity of the tyre, particularly in terms of load and need, and that could be one important reason for the break-up."

After discovering the problem, Michelin have already changed their fitting process to ensure there can be no repeat of the tyres being fitted the wrong way.

"You bet we have," said Dupasquier. "Everything is in place and everything has been done on all existing tyres and the tyres we are producing now."