Grapevine: Rankings: Loeb set to challenge Vettel

The Citroen driver leads the World Rally Championship by a handsome margin from his French compatriot Sebastien Ogier, and has not been beaten on the asphalt stages around Trier since it joined the WRC in 2002.

While an unprecedented eighth win on the rally would not be enough to move him into the top spot ahead of Sebastian Vettel, it would strengthen his current second place and enhance his chances of becoming number one for the first time since September 2009.

Ogier, back in the Citroen Junior Team for the German event, lies 23rd in the Castrol Rankings and would ease his way into the top 20 with a victory. A maiden podium finish for his team-mate Kimi Raikkonen (41) would move the Finn inside the top 35.

An outside contender for victory is Belgian Francois Duval, who has been on the podium four times in Germany and returns to the WRC for the first time since 'retiring' during the winter. He can expect a massive surge from his current 1986th place, especially if he makes it onto the rostrum.

One man destined to lose ground is Ford's Mikko Hirvonen, who lies 10th in the Castrol Rankings, but who is defending a near-perfect score from last year's corresponding event, Rally Finland, which he won.

If Hirvonen lives up to his usual form on asphalt, that will put his position under serious threat from US-based racers Will Power and Denny Hamlin.

Power leads the IndyCar Series after four wins in his Penske Dallara this year and the Australian returns to Sears Point for the first time since breaking a number of vertebrae in a practice crash there last year.

That crash meant that he did not score any Castrol Rankings points there in 2009, and so has a good chance to turn his current 16th place into a top-10 spot with a strong finish.

Challenging him for the race win - and the championship - will be Dario Franchitti (6), who won at Sears Point last year, and his Ganassi team-mate Scott Dixon (9). Both have big scores from last year's race to defend, so are more likely to find themselves losing ground in the Castrol Rankings.

The NASCAR Sprint Cup continues at the half-mile Bristol Speedway with Hamlin (11) and championship leader Kevin Harvick (12), close to places in the Castrol Rankings top 10 themselves. Champion Jimmie Johnson (5) won there earlier in the year though and starts as the favrourite again.

To see the full Castrol Rankings, please visit www.castroldriverrankings.com