  A new data-driven method, using $Z \rightarrow \mu^+ \mu^-$ decays, is
proposed to correct for charge-dependent curvature biases in spectrometer
experiments at hadron colliders. The method is studied assuming a detector with
a "forward-spectrometer" geometry similar to that of the LHCb experiment, and
is shown to reliably control several simplified detector mis-alignment
configurations. The applicability of the method for use in measurements of
precision electroweak observables is evaluated.
