Hi - probably the reason for the change >from GRUSZKA to GROSSMAN was
the desire to change >from a Slavic- and alien-sounding surname to a
Germanic surname, and the new name was picked because of the
similarity in sound of the first syllable.
Many Jews with Eastern European surnames changed their names to
German-sounding ones in the U.K. and U.S. because German Jews were
regarded more highly than Eastern European Jews. This attitude was
held not only by the gentiles but also by the already-established
German Jews, who had largely assimilated into the culture of their new
countries and looked with disfavor on the "uncivilized" arrivals from
Eastern Europe, with their strange garb, "primitive" Orthodox
religious beliefs, men in beards and women in shaytls, etc.
The change was sometimes made even among families still living in
Eastern Europe. My grandfather's family name was CHARNY, which means
"black" in Polish. At least one branch changed their surname to
SCHWARTZ (German / Yiddish for black) while in Lithuania and a few
more did so upon arrival in the U.S.