Pirelli has confirmed after analysing the recent run of rear tyre blowouts suffered by Jonathan Rea at Donington Park and Michael van der Mark and Jordi Torres at Misano there was 'no evidence' linking the problems but as a precaution will deliver two new rear tyre compounds for Laguna Seca.

The Italian tyre manufacturer came under fire after suffering a three high-profile tyre blows in two rounds when Torres suffered a cruel blowout while fighting for his first rostrum of the year on the Althea BMW in race two at Misano.

The Spaniard's tyre issue followed a similar incident which thwarted van der Mark on the Pata Yamaha who had been leading race one at Misano.

The problem had initially been thought to link back to the dramatic rear tyre blowout Jonathan Rea suffered while leading the Donington Park opening race in the closing stages, but after running analysis into the issue Pirelli has confirmed 'no evidence was found that might link the problems to a certain element composing the tyres'.

Pirelli believes the 'excessive stress' its tyres were placed under plus the high track temperatures caused an abnormal spike in internal tyre temperatures which caused the blowouts.

As a result, the Italian tyre manufacturer will supply two new rear compounds to Laguna Seca and has sent a reminder to all teams to keep within the minimum tyre pressures and correct use of tyre warmers. Pirelli's minimum rear tyre pressure is 1.65 BAR (23.9 PSI) which must be recorded from the first lap of the race.

Giorgio Barbier, Pirelli Moto Sports Activities Director, has defended its efforts and feels the manufacturer is somewhat restrained by the lack of data due to not all teams running sensors for tyre pressures.

"It is good to state these are standard products regularly purchased on the market and not prototypes like the ones used in MotoGP," Barbier said. "The power and the technological level of the bikes has also clearly increased compared to the past. The more the level of the tyre's performances increases, the more the product's 'sensitivity' to the smallest of external variables, such as the pressure increases.

"We should also mention the fact that the product's development hasn't progressed at the same speed as Pirelli's possibility to monitor its tyres during the race. In other championships the tyre manufacturer is able to know, in real time, the pressure as each bike is equipped with pressure sensors.

"For us, this kind of control is currently impossible as not every team has pressure sensors. The pressures, together with a correct utilisation of the tyre warmers, play a very important role in allowing tyres with an extremely high technological level to work properly."