Did they move to Texas?
Could you please tell me what relative socioeconomic class they were? Different classes moved for different reasons. Knowing their faith would also help.
Anyways, the poor Germans left for the sake of economic opportunity as 19th Century Germans were caught in the middle of huge power struggles in modern day Germany. The lower classes were milked for cash and labor and the prospect of a new life would have been very appealing.
The richer Germans also left for economic opportunity but not necessarily the same kind. Those with money went to America because they saw a huge emerging market waiting to be exploited. They would generally go, spend lots of money in investments and set up very successful operations like lumber mills.
Some Germans, regardless of class, left because of religious persecution.
So all this begs the question, what kind of Germans did you descend from?