First things first, I am aware of the existence of this [topic][1]. It's related, but old and my question haven't been discussed there. So I hope it's not wrong to start a new topic ... I'm currently searching for a vector bundle $E\to M$ (no conditions on the rank of $E$) such that $$ w(E) = 1 + w_2(E)+w_3(E) $$ with $w_2(E),w_3(E)$ both non zero. I've shown that : - If $w_2(E)=0$ then $w_3(E)=0$ (Wu's formula), so we can't really simplify the question. - $M$ can not have a $\mathbf Z/2$ cohomology engendered by a single element of degree $1$. In fact one can not have $w_2(E)=x^2$ with $x$ of degree 1. - $E\to M$ can not be the tangent bundle of $M$ (where $M$ is in this case a manifold). (Wu's formula for tangent bundle) If you have any ideas, It would be much appreciated. Thanks! [1]: https://mathoverflow.net/questions/163996/vector-bundle-for-prescribed-stiefel-whitney-classes