  In this paper, we consider the split even Clifford group $\Gamma^+_n$ and
compute the mod 2 motivic cohomology ring of its Nisnevich classifying space.
The description we obtain is quite similar to the one provided for spin groups
in [11]. The fundamental difference resides in the behaviour of the second
subtle Stiefel-Whitney class that is non-trivial for even Clifford groups,
while it vanished in the spin-case.
