  We compute the classical $r$-matrix for the relativistic generalization of
the Calogero-Moser model, or Ruijsenaars-Schneider model, at all values of the
speed-of-light parameter $\lambda$. We connect it with the non-relativistic
Calogero-Moser $r$-matrix $(\lambda \rightarrow -1)$ and the $\lambda = 1$
sine-Gordon soliton limit.
