  Motivated by puzzling characteristics of spin-glass transitions widely
observed in pyrochlore-based frustrated materials, we investigate effects of
coupling to local lattice distortions in a bond-disordered antiferromagnet on
the pyrochlore lattice by extensive Monte Carlo simulations. We show that the
spin-glass transition temperature $\TSG$ is largely enhanced by the
spin-lattice coupling, and furthermore, becomes almost independent of $\Delta$
in a wide range of the disorder strength $\Delta$. The critical property of the
spin glass transition is indistinguishable from that of the canonical
Heisenberg spin glass in the entire range of $\Delta$. These peculiar behaviors
are ascribed to a modification of the degenerate manifold from continuous to
semidiscrete one by the spin-lattice coupling.
