Rottweilers are larger and weigh more than German shepherds on average, so they're usually stronger animals. Many tests have been done on different dog breeds to determine the strength of each.
In tests conducted by National Geographic, German shepherds had a bite force of 238 pounds of pressure. The rottweiler came in at 328 pounds of pressure.
A study released in Behavioral Processes in 2011 suggested that the size and width of a dog's head can predict its strength and speed. Dogs with broad heads such as mastiffs and rottweilers are thought to be stronger than dogs with more narrow heads, such as German shepherds.