What is the relationship between radial wall width and groove stability in spiral rings?

The radial wall $b$ of the ring determines its resistance to dishing and its ability to stay seated in the groove. A wider radial wall increases the moment of inertia $I = \frac{t b^3}{12}$, which helps prevent the ring from twisting out of the groove under high thrust. However, a wall that is too wide makes installation difficult as the bending stress during installation $S_{inst} = \frac{E t (D_g - D_i)}{(D_g - t) D_i}$ may exceed the elastic limit, causing permanent deformation. The optimal ratio is typically $b \approx 10t$ for standard applications.