CHICAGO: Chicago may lead in the race to host the 2016 Summer Olympics, but history has shown the voting can be unpredictable and the other cities in the running cannot be counted out.

With 13 International Olympic Committee delegates due to tour Chicago on April 2-8, the US city is working to build on advantages that include the backing of President Barack Obama - who still owns a house in the city - and past successful US Games, analysts who follow the Olympics said on Tuesday. After Chicago, IOC delegates will visit the other bidders: Madrid, Rio de Janeiro and Tokyo. The jockeying will continue until the final vote in Copenhagen on Oct 2.

"There is no bid that has a greater chance than Chicago, but there are many ways that Chicago may not be selected," said Marc Ganis, president of Chicago sports consulting firm Sportscorp Ltd.