Why F1 cars keep getting heavier | F1 technology

The minimum weight for Formula One cars is set to jump from 642kg to 690kg in 2014 - well up from the original 1961 limit of 450kg. Why do F1 cars keep getting heavier?

Source: http://feedproxy.google.com/~r/f1fanatic/~3/swrbPlhIfr4/

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