Hard to say if the tires are too big or not. I believe for a 55-series, 195 should have been the correct profile to prevent what you have occurring with 16-inch rims.
I feel your pain. My W124 was eating 40-series tires (17" rims) at the rate of one set per 9-15 months! If I went to a 45-series tire, freeway dips always caused the scraping you describe. I now run a thicker tread on a 40-series tire, and also have this scraping issue...
Unfortunately, the sun isn't shining directly on the fender lip, or you could see the paint missing on the inner rear lip where the tire always contacts under those conditions...but the point of contact is somewhere between the 3 and 4 o'clock position...