The predictions of some constitutive equations for rheological behaviour at high rates of strain are investigated. One new result is the formal establishment of limits for shear flow of an integral model which uses the Seth strain measure. The work is related to earlier work on uniaxial and planar extension for rate equation models. Old and new results are tabulated and the behaviour of different models is classified. A recent idea of Harlen is used to ＇fix up＇ the upper convected Maxwell model tin the sense of removing the upper limit on rate of strain for steady extensional flow).