BARCELONA // Sebastian Vettel's rivals are hoping a new tyre compound and some off-season regulation changes may help them upset the German driver's dominance at the Spanish Grand Prix on Sunday.
Vettel has won three of the first four races and led a Red Bull Racing one-two at the Turkish Grand Prix last time out to establish the team as favourites to retain the drivers' title and constructors' championship.
There are few reasons to think the trend will change at the Circuit de Catalunya, where Vettel's teammate Mark Webber triumphed last year.
"We know the Barcelona circuit well from winter testing," Vettel said.
"It should be suitable for our car and our plan is to get the best team result possible.
"Historically, Barcelona is a circuit that is poor for overtaking, but with the [Drag Reduction System] this will be quite different."
Vettel expects the new adjustable rear wing to play a role, alongside the Kinetic Energy Recovery System power boost, while Pirelli's introduction of a harder compound tyre for the first time may test strategy.
But regulations and tires will have to have a big influence to affect a race where 16 of 20 winners have come from pole position, including the last 10.
Most teams will bring some kind of aerodynamic upgrade to Catalunya, and McLaren will be hoping for a significant improvement at a track 2009 winner Jenson Button calls "unforgiving".
Ferrari driver Felipe Massa, who won at the Catalan Circuit in 2007, believes the race will be more appealing for fans.
"Yes, I think the new rules mean there will be more overtaking," Massa said.
