30mm from the factory,, many mechanics use replacement nut that are 29mm I have been the owner of a car that had the 29mm replacement nut..
My present Fiero had 2 replacement clutch jobs ,,I imagine this is when the 29mm found its way to my car..
You need an impact wrench to remove this nut,,much ,much,much easier than breaker bar,, the rear nut is torqued to 200 ft pounds,,even my porky pig,prime cannibal bacon fat, lard butt,going airborne,out the door one last time , jumping full force on the bar would not break it loose..
[This message has been edited by uhlanstan (edited 01-18-2010).]