Anchor escapement the tooth sliding along its surface, pushing it. Then the tooth slides off the end of the pallet, beginning the cycle again. Neither the anchor escapement nor the deadbeat form, below, are self-starting. The pendulum must be given a swing to get them going. The backward motion of the escape wheel during part of the cycle, called "recoil", is one of the disadvantages of the anchor escapement. It results in a temporary reversal of the entire wheel train back to the driving weight with each tick of the clock, causing extra wear in the wheel train, excessive wear to the
Anchor escapement it unwinds. An escapement in which changes in drive force do not affect the rate is called isochronous. The superior performance of the deadbeat over the recoil is due to improved isochronism. This is due to the different ways changes in drive force affect the swing of the pendulum in the two escapements: When the deadbeat was invented, clockmakers initially believed it had inferior isochronism to the anchor, because of the greater effect of changes in force on the pendulum's amplitude. Recent analyses point out that the nonisochronism of the anchor can cancel the circular error of the pendulum. That