  Examining theories with an extended strong interaction sector such as
axigluons or flavour universal colorons, we find that the constraints obtained
from the current data on $t \bar t$ production at the Tevatron are in the range
of $\sim {\cal O}$ TeV and thus competitive with those obtained from the dijet
data. We point out that for large axigluon/coloron masses, the limits on the
coloron mass may be different than those for the axigluon even for $\cot \xi =
1$. We also compute the expected forward-backward asymmetry for the case of the
axigluons which would allow it to be discriminated against the SM as also the
colorons. We further find that at the LHC, the signal should be visible in the
$t \bar t$ invariant mass spectrum for a wide range of axigluon and coloron
masses that are still allowed. We point out how top polarisation may be used to
further discriminate the axigluon and coloron case from the SM as well as from
each other.
