Problem: Which of the following is true about the center distance of two meshing gears? Which of the following is true about the center distance of two meshing gears? The center distance is the center-to-center distance between the two mating gears. The center distance is the distance between the shafts that are carrying the gears. For external gears, the center distance is the sum of pitch radii. For the internal gears, the center distance is the difference of pitch radii. All of these