Pirelli will provide GP2 drivers with a fifth set of tires per weekend from the upcoming Silverstone races onward.
An additional set of prime tires will be permitted for each car on Fridays of race weekends, making a total of three sets of primes and two sets of options for the event, but one set of primes must be returned to Pirelli after practice.
Pirelli's racing manager Mario Isola said the change was designed to help drivers prepare better for qualifying and to encourage more action in free practice.
"By adding an extra set of softer tires to the weekend allocation in GP2, we are giving the drivers more options in terms of strategy and more experience of the tires," he said. "With just one set of the soft tires available to them up to now, the drivers have tended to use these just for qualifying, without the opportunity to test them in free practice first.
"Now they will have the chance to run on them in free practice as well, while saving a new set for qualifying. This will allow them to have more information with which to plan a strategy over the course of the weekend."