The calculated distance (air line) between Clausthal-Zellerfeld and Bochum is approximately 136 miles respectively 218 kilometers.
By car or train, the actual journey to Bochum is certainly longer, as only the direct route (as the crow flies) between Clausthal-Zellerfeld and Bochum has been calculated here.
Air line (approximately)
218 kilometers
118 nautical miles