  PDF fits in the HERAPDF1.0 formalism have been made to the combined HERA-I
inclusive data and the newly combined $F_2$(charm) data from the H1 and ZEUS
experiments. The charm data are found to be sensitive to the value of the charm
mass and the choice of the heavy quark scheme. This has consequences for the
predictions of $W$ and $Z$ cross sections at the LHC.
