Pirelli's new range of tyres for the 2014 Formula 1 season is more conservative, at least according to reports from its private testing in Bahrain.A three-day, Pirelli-organised test in Bahrain saw Red Bull, Ferrari, Mercedes and Toro Rosso get to grips with the new range albeit with their 2013 cars.The testing of the 2014 tyres, which will have to handle the higher torque of the new turbo engines, is taking place behind closed doors. Lap times and details are not being disclosed.INCREASED LAP TIMESItaly's Autosprint said: "The general indication is that the tyres are slower. Even with the same (2013) cars, the lap times are expected to rise because the tyre supplier is taking a more prudent approach."Pirelli had a tumultuous 2013 season, characterised by the tyre-exploding British Grand Prix and constant complaints about questionable durability and quality.Autosprint said F1's official tyre supplier has taken "dozens" of compound and construction combinations to Bahrain, but they all have one thing in common -- the internal kevlar belt. The report said: "The experiment with steel belts, which gave so many problems at the beginning of 2013, is over."