Consonantal environment may aid in specifying vowel identity by supplying critical information about timing. Several vowel pairs in American English are distinguished by temporal as well as spectral variables, and these temporal differentia vary with articulatory rate. Two studies were designed to explore the following paradox: When consonantal formant transitions are introduced into a steady-state vowel, holding syllable duration constant, a response shift is observed toward longer-vowel alternatives, even though steady-state duration has been reduced. The first study verified this finding for the vowel pair /ε/-/æ/ in comparisons of ♯V♯ and bVb continua. Pairs of continua were defined separately by F1 variation and by duration variation, and each continuum type evidenced the paradox. A second study varied the rate of symmetric consonantal transitions in F1-varying CVC continua (V = /ε, æ/, C = ♯, b, w/) in order to test whether transition rate might specify an articulatory rate that effectively scales vowel duration. Vowel responses did not vary monotonically with either transition rate or steady-state duration, but interacted with the perceived identity of the initial consonant. Listeners' judgments may demonstrate a sensitivity to constraints on the relative timing of consonantal and vocalic gestures. [This work was supported by NIH grant HD-01994 to Haskins Laboratories, and by the University of Michigan Society of Fellows.]