Quote Originally Posted by wedge
Michelin - there was a minimum width for the grooves but the grooves in the Michelins could be significantly narrowed in race conditions and therefore a wider contact patch at the fronts. There was no measurement post race which then Ferrari pushed for.
I don't believe that was the case, IIRC the Michelins deformed more under lateral loading and therefore part of the outside shoulder of the tyre would come into contact with the ground, increasing the contact patch but also increasing the width of the 'tread' in excess of that allowed. The Bridgestones had stiffer sidewalls that did not deform in such a way and were therefore disadvantaged as their contact patches would remain constant whatever the lateral loading. Michelin's defence was that if the outside shoulder came into contact with the ground then part of the inside of the tyre would lift off it so the width of the tread at any one time would be under the limit allowed. The FIA did not agree.