Oral stops in Swiss German show a three-way contrast, traditionally characterized as lenis /b, d, g/, fortis /p, t, k/ and long fortis /p:, t:, k:/. Fortis occur after long vowels, long fortis after short vowels, and lenis after both. Spectrographic analysis was performed on all stops in medial and final position for three Bernese speakers. Absence of voicing and lack of significant differences in voice onset times were noted, suggesting closure duration alone accounts for the three-way contrast: lenis are on average 57% shorter than fortis, and fortis 70% shorter than long fortis. Using the minimal set [ra:de] (`spin'), [ra:te] (`guess') and [rat:e] (`rat'), the salience of preceding vowel length relative to closure duration was examined in two perceptual experiments: The lenis stop was lengthened in 20-ms increments to long fortis length, and the long fortis stop was shortened to lenis length. The lengthened continuum shows a clear shift from lenis to fortis percept, but no shift to fortis long. The shortened continuum shows chance performance. Robust crossover effects in the lengthened continuum suggest vowel and consonant length are relevant to stop identification, while the shortened continuum suggests vowel length is primary.