  Analysis of both pulse timing and pulse shape variations of the isolated
pulsar PSR B1828-11 shows highly correlated and strong Fourier power at periods
\~ 1000, 500, and 250 d (Stairs et al. 2000). The only description based on a
free precession of star's rigid crust coupled to the magnetic dipole torque,
explains the 500-component, as the fundamental Fourier frequency, with its
harmonic 250-component (Link & Epstein 2001). In this paper, we show that if
the dipole moment vector varies with time with a period nearly equal to the
longest (probably fundamental) observed period (~ 1000 d), the dipole torque
may produce the all other harmonics. We also find the second and fourth
harmonics at periods ~ 500 and 250 d are dominant for small wobble angle ~ 3^o
and large field's inclination angle 89^o.
