  Event generators like Pythia play an important role in physics studies at the
Large Hadron Collider (LHC). While they make accurate predictions in the
central region, i.e. at pseudorapidities $\eta<5$, a disagreement between
Pythia and measurements in the forward region, $\eta>7$, has been observed. We
introduce a dedicated forward physics tune for the Pythia event generator to be
used for forward physics studies at the LHC, which uses a more flexible
modelling of beam remnant hadronization and is tuned to available particle
spectra measured by LHCf. Furthermore, we provide an uncertainty estimate on
the new tune in a data-driven way which can be used as a means of flux
uncertainty for future forward physics studies. We demonstrate an application
of our tune by showing the updated neutrino and dark photon spectra at the
FASER experiment.
