Tyre failures halt F1 practice in China

Formula 1's opening practice session for the Chinese Grand Prix was hit with two red flags on Friday as teams suffered a spate of tyre problems.Felipe Massa brought out the first red flag after 25 minutes following a spin at Turn 6 when his left rear tyre appeared to come off the rim and pitched him into a spin.

Television footage of the incident showed him apparently running over debris at Turn 1 prior to the incident.

With gravel littered across the track, and carbon fibre debris in the middle of the circuit, a virtual safety car period was turned in to a session stoppage.

At the restart, Massa again suffered a tyre problem on the same left rear corner – with the team spending time closely inspecting the damage.

Williams' immediate suspicion was that a problem with the rims was behind the two tyre failures - although they were not running a new design here.

"Something is touching the tyres or the wheel or whatever," Massa told Sky Sports F1. "We need to understand.

"We have no idea why we had the first problem, so we checked the car and went again. We had again the same problem on the out lap, and we don't understand why."Magnussen in trouble tooShortly before the first hour was complete, however, Kevin Magnussen returned to the pits with a damaged tyre and his left rear suspension broken after a high-speed failure on the back straight.

It was unclear if the broken suspension had been the cause of the problem or the result of an issue with the tyres.

Magnussen said afterwards: "I just felt something break - either the tyre or the suspension."

The session was again stopped to allow marshals to clear debris from the track.

The Shanghai circuit can be particularly challenging for the left hand tyres due to the long Turn 1 and banked Turn 13 corner.

A Pirelli statement said that the tyre issues on Massa's car did not appear to indicate a normal puncture.

"Investigation on both failures on Williams during FP1 show no signs of puncture," it said. "Air loss [was] connected to technical trouble.

"Investigation on Renault ongoing."