AUTO PACKAGE: Tire concerns threaten to overshadow battle for championship at German GP

Safety concerns over tires threaten to overshadow what is becoming an intriguing battle for the Formula One championship between three-time defending champion Sebastian Vettel, Ferrari's Fernando Alonso and several other drivers.

The sport was plunged into a crisis when four drivers, including race leader Lewis Hamilton and Ferrari's Felipe Massa, nearly crashed in Sunday's British Grand Prix after their tires burst. The sight of large chunks of debris showering down on cars and, in one case, a huge strip of rubber flying across the track prompted several current and former drivers to suggest the sport was sacrificing safety in a bid for more excitement.

"Without that tire problem, I could have made it to the podium because today I had a good feeling with the car," said Massa, who had similar problems in Bahrain and also nearly was killed in 2010 when he was hit by debris at the Hungarian Grand Prix.

The Brazilian also talked of a driver boycott — something dismissed by F1 boss Bernie Ecclestone — if the problem wasn't solved by this weekend's German Grand Prix.

"Now, our greatest concern revolves around safety. Even if I can't really tell what happened, it's unacceptable having to drive knowing you are not safe," Massa said. "Even if, luckily, nothing serious happened, what we saw is very dangerous."

On Monday, International Automobile Federation President Jean Todt said the young drivers' test scheduled for July 17-19 at Silverstone would be opened to all F1 drivers, although Mercedes would be excluded after holding unsanctioned tire tests in May. In-season testing was banned in 2009 amid cost concerns.

"Our priority is to ensure safety for all in Formula One and we believe the incidents at Silverstone represent a genuine safety concern for the drivers," Todt said. "We have thus taken the decision to alter the young driver test to allow teams to use drivers they deem fit to carry out tire development work in a bid to solve the problems we saw at the British Grand Prix. I believe it is fitting to carry out this work at the circuit upon which the issues were manifested."

Pirelli on Tuesday said the tires were safe if used in the correct way, blaming the blowouts on rear tires being mounted the wrong way by teams, low tire pressures and "aggressive" curbs on high corners at Silverstone. Still, it agreed to make tire changes for the German GP, including using a Kevlar belt — a fiber that is more resistant to punctures — instead of steel on its rear tires. The series will revert to 2012 tires from the Hungarian Grand Prix onward.

Alonso and Hamilton cautiously endorsed the changes Wednesday.

"I am satisfied, but only when we get there (Germany) will we have a better idea how it is for us," Hamilton said. "It's still a concern. We'll see how the weekend goes but I'm sure they've taken the right steps to make it safe."

The tire trouble at Silverstone is the latest controversy to hit Pirelli, which has come under fire over concerns its tires are wearing down too quickly and leading to races being decided by pit stops rather than action on the track.

It also took some of the limelight away from a thrilling race that saw pole sitter Hamilton give up the lead after his tire problems and then Vettel drop out with 10 laps remaining due to mechanical problems. Hamilton's teammate, Nico Rosberg, held off Mark Webber of Red Bull for his second win of the season.

Red Bull's Vettel remains the favorite to win another title but his retirement at Silverstone opened the door for his rivals — most likely two-time champion Alonso who understands time is running out if Ferrari wants to overtake Vettel and win its first drivers' title in four years.

"Mixed feelings to be honest," Alonso said after finishing third at Silverstone. "Happy for the points, we've reduced the gap a little bit in this race but the pace we saw this weekend is not good enough."

The Mercedes drivers, Hamilton and Rosberg, also seem to be emerging as a threat, after the team finally showed it had the pace on race day that it has demonstrated in qualifying. Hamilton, despite his early tire troubles, worked his way up from dead last to finish fourth. The team now is second in the constructors' championship behind Red Bull.

Raikkonen, who won the season-opening Australian GP, appears to be fading. He finished 10th in Monaco and 9th in Canada and missed out on a podium finish at Silverstone, overtaken in the final laps by Alonso and Hamilton after deciding not to switch tires late in the race. The 2007 champion finished fifth and said he was now hoping for a better showing in Germany, a race he has never won in 16 attempts.