ABS and tire size

[ReveC2.7]

E30's are new to me and find myself searching for answers but can't fine this one ..help from fellow owners would be appreciated.
Question posed-- When I hit 75-80mph the ABS light comes on / disengaging the ABS. Could my staggered tire height 0f 205 45's front to 225 50s in rear be the cause ?

Thanks !

[jlevie]

Yes. The ABS system assumes a square setup with the rolling diameters of all four tires being equal.