My last two 7 Series, last 2 X5s and my 2012 Rolls Royce Ghost all had Run on Flats. Horrible. Hard, noisy, bouncy and not smooth. My new '13 RR is running on 21" NON run-flats....and the difference is HUGE! Smooth, calm, comfortable and just so awesome!! I've said it so many time, but I am shocked and really confused why BMW and Rolls Royce all use run on flats. Crazy business choice!!
2013 Rolls Royce Phantom Sedan,
2013 Phantom Aviator Coupe, 2013 G63 AMG