We study the influence of theoretical systematic uncertainties due to the quark density on LHC experimental searches for Z'-bosons. Using an approach originally proposed in the context of the ABMP16 PDF set for the high-x behaviour of the quark density, we present results on observables commonly used to study Z' signals in dilepton channels.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3.