Correlation times (τ 𝑚𝑒𝑡 ) for methyl group rotation ranged from 5.5 ps to 22 ps, with faster timescales observed for surface-exposed residues like Ile44 (τ 𝑚𝑒𝑡 = 5.5 ps) and slower ones for core residues like Ile23 (τ 𝑚𝑒𝑡 = 22 ps), possibly due to steric interactions. For residues without well-defined nanosecond-scale motions (Ile3, Ile23, Ile30, Ile61), relaxometry-derived fast-motion order parameters (𝑆 𝑓 2 ) aligned well with those from high-field deuterium relaxation. However, for residues with defined nanosecond motions (Ile13, Ile36, Ile44), the analysis of relaxometry gave lower order parameters than those obtained from deuterium relaxation. Measurements of dipolar couplings in solids and nanoparticle assisted spin relaxation (NASR) in solution are in very good agreement with the lower order parameters obtained by relaxometry. Note that, of these three approaches, only relaxometry can determine the effective timescale for these motions.