Stoner's future may now lie on four wheels rather than two, after he successfully tested a V8 Supercar last December. Casey Stoner's future may now lie on four wheels rather than two, after he successfully tested a V8 Supercar last December. The sport's officials said he would be welcomed "with open arms" into the series should he decide on a change of motorsport direction. "Stoner has had a strong interest in V8 Supercars, and in particular Team Vodafone, having successfully tested the 888 Race Engineering cars on several occasions," V8 Supercars said in a statement on Friday. "He has attended numerous V8 Supercars events in recent years and has made no secret of his passion for the sport.

"V8 Supercars would welcome Stoner with open arms should he choose to make the switch from two wheels to four, following the likes of (Australia's former motorcycling world champion) Wayne Gardner into touring car racing." Casey Stoner on his way to pole position in last year's Australian MotoGP. Credit:Reuters Stoner said he had lost the passion for bike racing, which prompted his unexpected decision to quit. "After a long period of thought and numerous discussions with my wife and family, I have decided to stop competing at the end of the season," the Honda rider said. "After so many years taking part in this sport that I love, and with all the sacrifices that I have had to make, I no longer have the passion to continue and I think that it is best to stop."

Stoner, who also won the world title in 2007 with Ducati, became a father for the first time in February when his wife Adrianna gave birth to a baby daughter. Despite his blistering start to the season, Stoner has been critical of a series of technical changes to the sport he claims are undermining the championship. He has also been battling cramps in his arms that prove particularly painful under braking. Nine-time world champion Valentino Rossi, one of Stoner's great rivals, said he was shocked by the Australian's decision. "It's a huge surprise to me as it is for everyone else," said the Italian.

"It's bad news for the world of MotoGP. Loading "At the end of the season, we are going to lose a great rider and a great rival, but it's his decision." AAP