Bahrain GP: Sebastian Vettel surprised by Pirelli's compound switch

Pirelli had originally allocated the soft and hard compound but decided in the wake of the Malaysian Grand Prix to use the medium in place of the former.

While the switch is regarded as a boost for Red Bull, which has proved hard on its tyres this year, Vettel suspects that it was not necessary.

"I'm a bit surprised because historically Bahrain has been a circuit where the tyres could be more aggressive," said Vettel, who stopped three times on his way to victory here in 2012.

"Obviously this year, it has been a different story and they have gone for the same choice as in Malaysia.

"We will see how long the tyres last and how good they are."

Red Bull has struggled with the Pirelli rubber this year, with the team known to be keen on tyres that would allow the rapid RB9 to attack more in races.

FERRARI STILL SUPERIOR WITH TYRES

Vettel pointed to rival outfit Ferrari's strength in terms of tyre use, suggesting that his team needs to make a breakthrough in tyre management.

"Certainly, they [Ferrari] do a good job on Sunday," said Vettel.

"It was pretty clear in Australia that it worked well with the tyres and therefore had a very strong pace on Sunday.

"I don't expect any difference here and expect them to be strong again.

"But first of all we will look at ourselves and there are a couple of things we can do better working with the tyres, trying to get more range and more pace out of them."

Even though he was unable to fight for victory in China, Vettel is confident of being in the mix this weekend.

He controlled the Bahrain race from start to finish last year despite a strong challenge from Kimi Raikkonen, and suspects that Red Bull's disappointing China performance will not carry over.

"There is no reason why we shouldn't be competitive," he said.

"We have a good car, we proved that in Malaysia.

"China is a very specific track, it's more front-limited than most of the other circuits, whereas this is a normal track.

"I'm looking forward to tomorrow to see how we do."