Detailed comparison of temperature dependences of segmental (tau(alpha)) and chain (tau(n)) relaxation times shows that decoupling of these relaxation processes occurs (the ratio tau(n)/tau(alpha) starts to drop) at a similar range of tau(alpha) similar to 10(-5)-10(-7) s regardless of a polymer and its molecular weight. The degree of decoupling depends on polymer and is stronger in more fragile systems. The most intriguing result is a rather universal temperature dependence Of tau(n) observed for the analyzed polymers when it is plotted vs T-g/T. These observations call for a revision of current models describing the microscopic friction coefficient in polymer melts.