  The discrepancy between the FOPT and CIPT approaches for hadronic $\tau$
spectral function moments constitutes the major theoretical uncertainty for
strong coupling determinations from tau decay data. We show the discrepancy can
be analytically understood since the Borel representations -- which have been
assumed to be identical for both approaches previously -- differ in the
presence of IR renormalons. This implies that the OPE condensate corrections
are different for both approaches and that the discrepancy may eventually be
reconciled. In the talk we explain the difference and some mathematical aspects
of of the FOPT and CIPT Borel representations and show numerical results.
