By Alasdair Fotheringham SERRA SAN BRUNO, Italy, May 7 (Reuters) - Tour de France champion Bradley Wiggins has yet to show the form of last season that would make him top favourite for the Giro d'Italia, according to Juan Jose Cobo, the last non-Team Sky rider to beat the Briton on a Grand Tour. "He's not necessarily the strongest rider," Spaniard Cobo told Reuters before Tuesday's fourth stage where Wiggins lost 17 seconds as the peloton split in the final kilometres. "Personally I think (Italian) Vincenzo Nibali is equally likely to win. ...
