Language-specific maximal size restrictions on syllables have been defined using frames such as moraic structure. In General American English, a trimoraic syllable template makes largely successful predictions about contexts where tense/lax vowel contrasts are neutralised, but neutralisation preceding a coda rhotic has not been adequately explained. We attribute the apparent special properties of coda /ɹ/ to two characteristics of its representation, informed by our articulatory investigation: sequential coordination of dorsal and coronal subsegmental units and a high blending strength specification, corresponding to high coarticulatory dominance. Characteristics of coda laterals are compared. Our approach employs phonological representations where sequencing is encoded directly among subsegments, and coordination is sensitive to strength. Mora assignment is computed over sequencing of subsegments, predicting that complex segments may be bimoraic. The account brings phonotactics for rhymes with postvocalic liquids into line with the trimoraic template, and supports representing coordination and strength at the subsegmental level.