Yeah tyson was a bad example
But just looking at the last few TDF winners...
2012, Bradley Wiggins, born in '82, so he must be 31 or 32.
2011, Cadel Evans born in '77... so *at least* 34
2010, Andy schleck, '85, at least 24
2009, Alberto Contador, '82, at least 26
2008, Carlos Satre, '75, at least 33
2007, Contador again, at least 26
2006, Óscar Pereiro Sío, '77, at least 31
And...well... I won't get into who might not have won the last 7 tours before that
Still, of the last 7 tour de france winners, only 3 have been in their 20s, and only 1 of those in their early 20s