NURBURGRING, Germany - With the threat of a drivers' strike hovering over the Nurburgring, the International Automobile Federation has moved to make sure there will be no more tyre blowouts.There were five dangerous blasts at the 2013 British GP at Silverstone, after which Pirelli complained that teams were swopping rear tyres left to right and running extreme cambers and pressures. Federation race director Charlie Whiting issued a statement insisting teams must now follow Pirelli's precise recommendations.'BOYCOTT UNDERSTANDABLE'The recommendations include precise pressures and specified camber angles and the rule was applied immediately to be monitored by official scrutineers and stewards.Mercedes boss Ross Brawn said that the drivers' boycott threat was "understandable"; he had even considered pulling Lewis Hamilton and eventual winner Nico Rosberg out of the Silverstone race.Pirelli's Paul Hembery said he was "surprised" by the drivers' position after clarifying the situation in a meeting on Wednesday.Red Bull's Christian Horner, however, said Formula 11 should "respect" the drivers' stance and said: "Who can blame them?" Despite the image-damaging situation, however, Hembery said Pirelli would not let the tyre chaos change its decision to stay in F1 beyond its 2013 contract.Hembery said: "You don't walk away in difficult times. That's the time to work harder and make sure you do a better job."