Low temperatures affect the properties of Polyurethane but without degradation. Below 0 degrees C, an increase in Young’s modulus, with a corresponding increase in Shore Hardness, tensile and tear strength plus torsional stiffness will be observed and resilience will decrease.  Torsional stiffness increase more rapidly below 25 degrees C but brittleness does not occur until circa -60 C to -80C.  The application of heat or heat generated by flexing will reverse the effects.