  Roughly perpendicular to SS433's famous precessing jets is an outflowing
"ruff" of radio-emitting plasma, revealed by direct imaging on milli-arcsecond
scales. Over the last decade, images of the ruff reveal that its orientation
changes over time with respect to a fixed sky co-ordinate grid. For example,
during two months of daily observations with the VLBA by Mioduszewski et al.
(2004), a steady rotation through ~10 degrees is observed whilst the jet angle
changes by ~20 degrees. The ruff reorientation is not coupled with the
well-known precession of SS433's radio jets, as the ruff orientation varies
across a range of 69 degrees whilst the jet angle varies across 40 degrees, and
on greatly differing and non-commensurate timescales.
  It has been proposed that the ruff is fed by SS433's circumbinary disk,
discovered by a sequence of optical spectroscopy by Blundell et al. (2008), and
so we present the results of 3D numerical simulations of circumbinary orbits.
These simulations show precession in the longitude of the ascending node of all
inclined circumbinary orbits - an effect which would be manifested as the
observed ruff reorientation. Matching the rate of ruff precession is possible
if circumbinary components are sufficiently close to the binary system, but
only if the binary mass fraction is close to equality and the binary
eccentricity is non-zero.
