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      09-17-2012, 05:14 PM   #3
New Member

Drives: 550i sport
Join Date: Nov 2010
Location: San Juan

iTrader: (0)

I'm also in PR with a 2011 550 sport package. After 18 oem(Goodyear, Bridgestone, Dunlop) tires damaged the first year of ownership I installed the same Dunlops but from the 7 series with a bigger sidewall(245/45/19 front & 275/40/19 rear). Have not changed a tire in over a year. Actually wore down the first set of tires. The problem with the oem size is the load index is too low for the weight of the car, specially the front so when the suspension hit a pothole the tire collapse and get cut by the wheel edge. With the higher sidewall there is a higher load index and more space for cushioning the blow before the wheel hit the tire. Just enough to prevent the damage. That is why this tire issue is not as big on the 7 series. There is a small diameter/circunsference diference between sizes but actually works in our favor. Mileage read a little bit slow. I almost traded the car last year before figuring this out. Since then no problems on the same roads with the same holes. No more ding!! ding!! after the impact. Finally was able to enjoy the car. If you switch to no run flat on this same roads is a matter of time before needing a tow truck because of a flat. I was never stranded always made it to the dealer for replacement. No space for a spare. Hope this help.