The calculated distance (air line) between Predeal and Piatra Neamţ is approximately 105 miles respectively 168 kilometers.
By car or train, the actual journey to Piatra Neamţ is certainly longer, as only the direct route (as the crow flies) between Predeal and Piatra Neamţ has been calculated here.
Air line (approximately)
168 kilometers
91 nautical miles