Answer
The radial wall $b$ (the width of the material cross-section) has a linear relationship with the spring rate $k$ and an inverse relationship with the stress $\sigma$. According to $k ∝ b$ and $\sigma ∝ 1/b$, doubling the radial wall will double the spring's stiffness but halve the stress for the same deflection. In space-constrained designs, increasing $b$ is often the only way to increase the load capacity without increasing the axial height (thickness $t$). However, a wider radial wall increases the risk of 'clashing' or interference with the bore or shaft during expansion. The designer must ensure that $O.D._{max} = O.D._{free} + \text{expansion}$ is always less than the Bore Diameter. If the wall is too wide, the spring may also become too stiff to install without permanent set.
