| NUERBURGRING, Germany
NUERBURGRING, Germany Formula One teams have backed drivers who threatened to boycott this Sunday's German Grand Prix if there is a repeat of the tyre chaos which rocked Silverstone last weekend.
The Grand Prix Drivers' Association, which represents most but not all of those on the grid, announced on Thursday that they will not race if the blow-outs seen in Britain occur again and endanger lives.
Tyre supplier Pirelli has brought upgraded rears to the Nuerburgring with an inner belt made of the synthetic fibre Kevlar rather than steel and teams hope it solves the problem.
Guidance has also been issued to teams about the correct usage of the tyres and pressures required.
"It's the drivers' position at the end of the day and you've got to respect that. They were concerned about what they saw last week - who can blame them at the end of the day?," Red Bull boss Christian Horner told Sky Sports television on Friday.
"Hopefully it's not going to come anything near to that, but I just think they've laid down a marker to say 'we want this sorted'. We've got a different product here this weekend so I'm sure Pirelli are on top of it.
"But nobody wants to be in a position that we were in last Sunday. I think with hindsight (race director) Charlie (Whiting) would even have stopped the race."
Horner's comments were echoed across the paddock with the first two practice sessions in Germany passing without incident.
"I have some sympathy with the feelings of the drivers," Marussia sporting director Graeme Lowdon said.
"There is no way we, or any of the other teams, would put our drivers in a position that we felt was unsafe."
Any boycott would not be the first in the sport.
The most recent was in 2005 when seven teams pulled out of the U.S. Grand Prix because of tyre safety fears.
Pirelli motor sport director Paul Hembery told reporters that the teams had been assured the new tyres were safe after "underestimating" the situation at Silverstone.
"We explained the changes here and the changes going forward, which we believe are in completely the right direction for them," he said.
"We've written to Charlie and asked him to write to the teams, defining what we require because despite last weekend we've still had some people asking to do things we didn't want them to do."
Hembery said Pirelli made around 1,000 new tyres in 48 hours at their factory in Turkey to meet the deadline for Germany.
Another change is on the way from Hungary onwards in three weeks with Pirelli reverting to the 2012 constructions.
A Silverstone test from July 17-19 will let teams readjust to another set of tyres, with potential aerodynamic implications given the 2013 cars are designed differently to last year.
Former McLaren technical head Paddy Lowe, bedding in as the new executive director (technical) at Mercedes, thought it could have some impact on performance with his improving outfit now second in the constructors' standings having laboured last year.
"There are differences but we are aware of those differences because it's a tyre we used last year, so we can look at that...and optimise the car around that," he told his first news conference as a Mercedes employee.
Formula One faces more upheaval in 2014 with the biggest change in decades, with the old V8 engines to be replaced by a new 1.6-litre V6 turbocharged unit with energy recovery systems.
There will be a knock-on effect for tyres and Pirelli and the teams are working on a potential special test following the Brazil Grand Prix at the end of this season.
(Editing by Alan Baldwin)