A four parameters model including collective rotational energies to fourth order is applied to reproduce the ÃŽâ€I=2 staggering in transition energies in four selected super deformed rotational bands, namely, 148Gd (SD6), 194Hg (SD1, SD2, SD3). The model parameters and the spin of the bandhead have been extracted assuming various values to the lowest spin of the bandhead at neares...