For a fixed \(\vartheta ^2=1/m\) , \(m \in {\mathbb {N}}_+\) , let \(x \in [0, \vartheta )\) and \([b_1(x) \vartheta , b_2(x) \vartheta , \ldots ]\) be the \(\vartheta \) -expansion of x. In this paper, our objective is to investigate the relationship between the growth rate of the largest digit and the convergence rate for the \(\vartheta \) -expansion of an irrational number \(x \in \Omega := [0, \vartheta ) \setminus {\mathbb {Q}}\) . We demonstrate that the Hausdorff dimension of the set comprising irrationals with a specified relative growth rate is complete.