Abstract: A chordal action isolation wheel assembly for reduction of noise in track-laying vehicles by using a pendulous isolation wheel to isolate chordal track forces from a smaller drive sprocket. The drive sprocket is mounted on a drive shaft and one end of a pendulous arm is rotatably connected to the drive shaft. The isolation wheel is rotatably mounted on the other end of the pendulous arm and an endless track is trained about both the isolation wheel and the drive sprocket with only a small portion of the periphery of the drive sprocket contacting the endless track. The larger diameter of the isolation wheel causes a gentle lowering of the endless track onto the drive sprocket to reduce the force transmitted to the sprocket wheel and reduced noise. Chordal impacts of the track shoes occur against the isolation wheel, and the resulting vibrational energy is absorbed by the pendulous action of the isolation wheel assembly.