Grapevine: Hamilton under threat from Loeb

The McLaren driver leads the Formula 1 World Championship and has held second spot in the Castrol Rankings behind Sebastian Vettel for the last five weeks.

However, with McLaren having fallen behind Vettel's Red Bull team and Ferrari in the speed stakes, the British ace will have his work cut out in his hunt for a third grand prix win of the year.

To make matters worse for the Briton, World Rally champion Loeb is only a handful of points behind him, and is likely to overtake Hamilton if he can win this weekend's Rally Finland.

Should Castrol Rankings leader Vettel have a disastrous race of his own, Loeb (right) could even take over the number one spot, although such a set of circumstances is unlikely to arise.

While fellow F1 title challengers Mark Webber (4) and Jenson Button (6) are unlikely to have their positions change this weekend, German Grand Prix winner Fernando Alonso just might.

The Ferrari driver (9) is not far behind IndyCar Champion Dario Franchitti and another victory could move him as high as seventh - a position currently occupied by Ford rally star Mikko Hirvonen.

His Ferrari team-mate Felipe Massa climbed 21 spots to 41st with his runner-up spot at Hockenheim. Should he bury the demons of a horrible qualifying accident at the Hungaroring last year and win, he will move inside the top 30.

Expect more gains from Mercedes' seven-time World Champion Michael Schumacher (78), who is likely to move into the top 70 regardless of where he finishes.

Watch out too for Lotus men Jarno Trulli (65) and Heikki Kovalainen (49), both of whom are set to drop down the order after scoring big Castrol Rankings points in the corresponding race last year.

To see the full Castrol Rankings, go to .