Mon Nazir 30

The gemara says that according o R' Yosi b. Yehudah it makes sense that the child making a condition that it mends all Sfeikos, even if he turns the age to make Nedarim in middle of the thirty days, but not according Rebbe.

Tosfos explains: the idea is, if the son gets his own identity within the Nazir of the father, then the father's Nazirus stop cold turkey, and then start his own Nazirus. Since it's stopped in the middle, he cannot bring Korbonos for it, and his own Nazir starts, since his father's hasn't finished, it's as his father's never started.

However, according to R' Yosi, since it's only the age of Nedarim, which is rabbinic, it's not strong enough to break the father's Nazir. Therefore the Nazirus finishes until the end. However, Rebbe refers to actual Simanim to become a gadol, which is from the TOrah. Therefore it has the power to stop the father's Neziros cold turkey. Therefore if he gets these Simonim in the middle of the Nazirus, it stops the fathers Nazirus, Thus you don't have a definite Chiyuv until sixty days after teh Father's Nazirus