  We introduce a large class of bicovariant differential calculi on any quantum
group $A$, associated to $Ad$-invariant elements. For example, the deformed
trace element on $SL_q(2)$ recovers Woronowicz' $4D_\pm$ calculus. More
generally, we obtain a sequence of differential calculi on each quantum group
$A(R)$, based on the theory of the corresponding braided groups $B(R)$. Here
$R$ is any regular solution of the QYBE.
