Gearbox failure 'risk' too high - Mercedes

Apr.14 (GMM) Mercedes says leaving Lewis Hamilton's broken gearbox in his car in China was too great a "risk".

In a blow to the reigning world champion's hopes of ending his losing streak to teammate Nico Rosberg this weekend, Mercedes announced on Thursday that a gearbox change will result in a five-place grid penalty.

The gearbox was reportedly damaged when Valtteri Bottas collided with the Briton in Bahrain two weeks ago, although Hamilton went on to finish the race.

But Germany's Auto Motor und Sport reports from Shanghai that post-race checks showed that a differential bearing was damaged.

"It could still last 600 kilometres, but maybe only 100km," a Mercedes engineer is quoted as saying.

"The risk of leaving it in there was just too great."

The report, penned by respected correspondent Michael Schmidt, said Hamilton agreed with the decision to change the gearbox when told of the possibility of failure.

It means the highest Hamilton can start Sunday's Chinese grand prix is sixth. He is already 17 points behind Rosberg in the drivers' championship.