Steven Tyler's banged an astronomical amount of groupies over the years -- but even he's calling B.S. on Ric Flair's claim that he got 10,000 chicks to ride "Space Mountain."
We got the Aerosmith legend leaving LAX ... and you can tell he thought The Nature Boy's number was comical -- joking he had him beat before comparing him to rockstar Gene Simmons (who says he slept with 5,000 chicks himself).
But Tyler hit Naitch with a low blow before he rode off into the night, telling TMZ Sports how he really feels -- "that guy's full of sh*t."
As for Steven's number ... sorry, guys -- he was "too busy getting high" to count.