will replacing rf tyres make a difference to the ride

my wife has a chronic neck injury and can differentiate the ride between my current '04 525 and my previous 08' 528i. we both agree that the ride is more harsher and with the vehicle being relatively new i have to assume a lot of the road energy is coming thru the tyres. has anyone had an experience of replacing the rf with new conventional tyres. i understand the disadvantage of the spare etc, but i need to find improvements in the ride of the car. all comments appreciated. Edit/Delete Message