My great great grandfather, Fredrick Reitinger was born in Germany and came to the US sometime in the 1840's, settling in York County, PA. He later served in the Union Army during the Civil War but saw little action because of cronic illness. Later the family moved on to Adams County (Gettysburg!) My father, William Ridinger, now deceased, was born in Gettysburg and became somewhat of an authority on the Civil War and served as a National Parks Guide to the battlefield during his retirement from teaching. He told me when I was a boy that Fredrick is a small footnote in history because he, along with his wife are buried in the National Cemetary at Gettysburg, his wife (her name escapes me) being the first civilian ever interred in a National Cemetery.
As far as my branch of the name Reitinger goes, I'm not completely sure when it was changed to Ridinger or for what reason. I haven't done much research but what I have found is very confusing. During the 1800's direct line family members have spelled it Ridinger, Reidinger and Reitinger. Fredrick himself used both Reid and Reit versions. I believe the first sylable was always pronounced as a long "i" as in the word riding. That would be consistent with the German pronunciation of "ei". I always believed the name was changed in order to anglicize it even though the name Ridinger is also German in origin.
This probably doesn't help you in your search very much but I thought you might like hearing from a follow traveler of sorts.