The calculated distance (air line) between Rüdesheim am Rhein and Nürnberg is approximately 145 miles respectively 234 kilometers.
By car or train, the actual journey to Nürnberg is certainly longer, as only the direct route (as the crow flies) between Rüdesheim am Rhein and Nürnberg has been calculated here.
Air line (approximately)
234 kilometers
126 nautical miles