  We derive perturbativity constraints on beyond standard model scenarios with
extra gauge groups, such as $SU(2)$ or $U(1)$, whose generators contribute to
the electric charge, and show that there are both upper and lower limits on the
additional gauge couplings, from the requirement that the couplings remain
perturbative up to the grand unification theory (GUT) scale. This leads to
stringent constraints on the masses of the corresponding gauge bosons and their
collider phenomenology. We specifically focus on the models based on
$SU(2)_L\times U(1)_{I_{3R}} \times U(1)_{B-L}$ and the left-right symmetric
models based on $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$, and discuss the
implications of the perturbativity constraints for new gauge boson searches at
current and future colliders. In particular, we find that the stringent flavor
constraints in the scalar sector of left-right model set a lower bound on the
right-handed scale $v_R \gtrsim 10$ TeV, if all the gauge and quartic couplings
are to remain perturbative up to the GUT scale. This precludes the prospects of
finding the $Z_R$ boson in the left-right model at the LHC, even in the
high-luminosity phase, and leaves only a narrow window for the $W_R$ boson. A
much broader allowed parameter space, with the right-handed scale $v_R$ up to
$\simeq 87$ TeV, could be probed at the future 100 TeV collider.
