2011 rule changes - fixed weight distribution 03 February 2011
To coincide with the introduction of Pirelli tyres, the FIA have imposed a mandatory weight distribution range for 2011. The standardised distribution of 45.5-46.7 percent front, 53.3-54.5 rear will ensure one team alone doesn't strike lucky and stumble upon the perfect set-up for the as-yet-unknown Pirelli rubber (thus potentially prompting others into costly wheelbase changes). During the qualifying session a car on dry tyres can't weigh less than 342kg at the back and 291kg at the front.
FIA Technical Regulation
4.2 - For 2011 only, the weight applied on the front and rear wheels must not be less than 291kg and 342kg respectively at all times during the qualifying practice session. If, when required for checking, a car is not already fitted with dry-weather tyres, it will be weighed on a set of dry-weather tyres selected by the FIA technical delegate.