Red Bull drivers need to get back on track

Lewis Hamilton, the championship leader, will hope to take advantage of any more rifts in the Red Bull camp.

Parity, performance and unfulfilled potential. Such are the dominant themes as Formula One teams prepare for this weekend's German Grand Prix at Hockenheim, the first of back-to-back races prior to the sport's summer recess. Red Bull-Renault have spent almost as much time pledging equality this season as they has preparing cars - and the story continues to create headlines. The team have consistently denied allegations that Sebastian Vettel is given preferential treatment but did not help their own cause 12 days ago at Silverstone, where a new front wing was removed from Mark Webber's car to replace one that had broken on the German driver's car.

Dietrich Mateschitz, the owner, insists, however, that his drivers are - and will continue to be - treated as equals. Speaking to German newspaper Kleine Zeitung, the Austrian said: "Having No 1 and No 2 drivers is not my racing philosophy. You cannot just programme a champion." Webber won at Silverstone, despite the wing controversy, and also scored a comfortable victory in Germany last season. That race, though, took place at the Nurburgring rather than the ultra-flat Hockenheim. The German GP is unique on the current calendar in that it alternates between two circuits.

Lewis Hamilton, the championship leader, triumphed at Hockenheim in 2008, and the McLaren-Mercedes team have been working flat out to fine-tune the exhaust-blown diffuser that was tried but discarded at Silverstone. The other leading teams are already using such systems. "We're under no illusions," said Martin Whitmarsh, the McLaren team principal. "We need to add further performance if we are to remain at the forefront in the title race."

Hamilton and Jenson Button, his teammate, will undertake a serious test programme during today's free practice session, comparing new and old diffusers before deciding which to use for the balance of the weekend. Ferrari, meanwhile, continue to wrestle with the unpalatable truth that they trail McLaren and Red Bull in the championship, despite an obvious upturn in form during the past three races. Lapped traffic cost Fernando Alonso a possible victory in Canada and likely podium finishes were frittered away by circumstance at both Valencia and Silverstone.

After the British GP, Stefano Domenicali, the team principal, said: "We are angry that we did not get the result of which we were capable, but this anger must be turned into a positive force. If we knuckle down and continue calmly with car development, the results will come." Mercedes GP are participating in their home grand prix as a works team for the first time since 1954. They have some new chassis upgrades, but unless the top three trip up spectacularly their best hope remains a podium finish.

Farther back in the field, Sakon Yamamoto gets another opportunity with the cash-strapped HRT team: Bruno Senna returns to the fold after missing Silverstone, however, and Karun Chandhok steps down to accommodate the Japanese driver. [e-mail]