hyphsubst conflicts with inputenc

Question

If I load inputenc in combination with hyphsubst the hyphenation works partially. It works for many words, but it does not work for 'Starrkörpertransformationsparameter' if inputenc is loaded

hyphenation working:

\RequirePackage[ngerman=ngerman-x-latest]{hyphsubst}

\documentclass[ngerman]{scrbook}

% \usepackage[utf8]{inputenc}
\usepackage{babel}

\begin{document}
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
\end{document}

hyphenation does not work:

\RequirePackage[ngerman=ngerman-x-latest]{hyphsubst}

\documentclass[ngerman]{scrbook}

\usepackage[utf8]{inputenc}
\usepackage{babel}

\begin{document}
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
\end{document}

Answer 1

It's not a problem due to inputenc. You also need \usepackage[T1]{fontenc} or TeX won't hyphenate words past an accent.

In your example without inputenc, hyphenation points are found, but just because the accented characters are ignored.

\RequirePackage[ngerman=ngerman-x-latest]{hyphsubst}

\documentclass[ngerman]{scrbook}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}

\begin{document}
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
  Starrkörpertransformationsparameter
\end{document}

Slightly different results are obtained if \usepackage{microtype} is loaded, but this is expected; here's the result, the text is the same as before, the preamble is

\RequirePackage[ngerman=ngerman-x-latest]{hyphsubst}

\documentclass[ngerman]{scrbook}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{microtype}