And thats bull. I have more damage on the underside of my rig then most people with larger tires. My frame rails are completed smashed, gas tank is reduced by a couple gallons, t-case is above frame rails, etc, etc.
It all about knowing how to drive, not tire size.. You don't hop the rear end, you don't wedge a tires. Spinning tires till they hook also break stuff.
Classic example is Tim Hardy and his sammi. He has some small axles on 33's forever and follows everyone everywhere and hardly ever breaks. He knows how to drive and avoids what breaks axles.
Another local guy has a XJ on 34's with stock axles and it looks similar to Hardy's sammi and he wheels it all over the place, never had any issues with the rear 35.
I decide I would spend 500 on mine and that would be it, was well spent and last quite awhile with no issues till I replaced it.