Efficiency generally decreases with smaller sprocket and chainring sizes. They also have different cam and crank sprocket reluctor configuration. Initially this was by means of a pair of sprocket wheels on a common axle. It is driven by a toothed wheel called a sprocket. AMV8 are the lower cam timing sprocket and the timing chain. It was driven from the rear drive sprocket with the turret situated forward. The drive sprocket was located at the rear of the hull. Like the T-34, the DB design had a rear drive sprocket. The tracks also had a tendency to override the rear sprocket, resulting in immobilisation. Phasing is implemented by a computer-controlled, oil-driven adjustable cam sprocket. The low-mounted sprocket limited the obstacle clearance height. On this drum sits either a fixed sprocket or an exchangeable one. The track is driven by a drive sprocket at the front. It required a new drive sprocket, with 14 teeth instead of 13. These bars are laminated bars with a small sprocket at the nose.