You shouldnt as the tyre diameter is too different. The diameter of a 205(mm) 60(%) 16(in) = 60% of 205mm, so 123mm whereas the diameter of a 205(mm) 55(%) 16(in) = 55% of 205mm, so 113mm. The 10mm difference is enough to make your speedometer inaccurate & your fuel economy less as the 55 tyre will have to rotate more times than the 60 tyre to cover the same distance.
