  We discuss the possibility of using the observables deduced from the angular
distribution of the $B\to D^{(\ast)} \ell\bar{\nu}$ decays to test the effects
of lepton flavor universality violation (LFUV). We show that the measurement of
even a subset of these observables could be very helpful in distinguishing the
Lorentz structure of the New Physics contributions to these decays. To do so we
use the low energy effective theory in which besides the Standard Model
contribution we add all possible Lorentz structures with the couplings (Wilson
coefficients) that are determined by matching theory with the measured ratios
$R{(D^{(\ast)})}^\mathrm{exp}$. We argue that even in the situation in which
the measured $R{(D^{(\ast)})}^\mathrm{exp}$ becomes fully compatible with the
Standard Model, one can still have significant New Physics contributions the
size of which could be probed by measuring the observables discussed in this
paper and comparing them with their Standard Model predictions.
