14" Tire info/advice

I was planning on going with a 225/60 up front & a 245/60 out back but I was told that if I use a tire that is wider than recommended it will "mushroom" on the rim & flex too much. I am really working on setting my car to handle well so I do not want to put all this time & money into the suspension & then ruin it with the wrong tires.
Thanks for the info Johnny.