Former Tour de France winners Bernard Hinault and Miguel Indurain say Lance Armstrong is not necessarily the greatest cyclist ever.
Armstrong, 33, ended his career with an unprecedented seventh consecutive victory in the race on Sunday.
"You cannot compare. The bikes are different, the opponents are different," said France's Hinault.
And Spain's Indurain added: "He is the best of his generation, but we shouldn't compare him to other eras."
Hinault won the Tour five times and was the last Frenchman to do so in 1985, while Indurain won the Tour each year from 1991 to 1995.
Hinault added: "Armstrong was obsessed by the Tour. He does everything to do it and as he wins, he is the one who is right.
"The others, who finish second or third, are not good. They have not understood everything yet."
And Indurain hinted that Armstrong's total focus on Le Tour might tarnish his legacy.
"Armstrong has proved that he has been the greatest rider in the Tour, but that was the only race he really competed in to win," said Indurain.
"He has always concentrated his efforts on the French race and used the others as a test bed."
And Indurain, who also won the Giro d'Italia twice, said a new champion could emerge capable of surpassing Armstrong's feat.
"I think there will be two or three more open races where a lot of leaders will compete ferociously for the triumph until another dominant leader emerges to establish a new era," said Indurain.
"Sooner or later a rider will emerge who will win more Tours. In every sport we have seen how the records eventually get broken and cycling is no exception."