I purchased this vehicle used at a dealer in Virginia. I drove it home to Chelsea Alabama, outside Birmingham. After a couple of days, my front right tire went flat. I took it to the dealer and they said the flat tire was caused by a cracked rim and required both to be replaced. Almost $3,000 for tire and rim. I continued to drive the car, maybe 4,000-5,000 miles and I had another tire go flat. This was the drivers side rear tire. This was a Pirelli 285/35 R20 run flat tire. Again when I took it to the dealer, this rim was cracked and also needed to be replaced along with the tire. $2,790. The car has 55,000 miles and is meticulously maintained. And I do not drive on rough roads. The dealer consistently states it was due to hitting a pot hole which a) is not the case in both these incidents, and b) a rim should not break from running into regular small imperfections in the road. Ive been in the auto manufacturing business for 38 years and have never, ever had a rim fail, not once but twice in 4 months on the same vehicle. After investigating, this is happening all over. My feeling is the rim has not been sufficiently designed to support the weight of this vehicle. And now, every time I take the car out, I fear for my life and my families life. Frankly, the car is not safe because the rims can and will crack and split under regular driving conditions! This can cause a blowout and possible injury or death. This cost and the cost of my safety should be covered by Mercedes. They should replace these rims with stronger, more properly designed rims to ensure my families future safety!