Problem with the sidewalls of your low profile contiprocontact tires. these came equipped on my wife's 2015 buick verano as oem ' p235/45 r18. in the past 60 days, she has had 3 of these tires become damaged, go flat and have to be replaced due to damage to the sidewall. additionally, my mother-in-law has also had to replace one of these tires on her 2015 verano. my wife's tires had between 18,000 and 22,000 miles on them while my mother-in-law's had 7,500 miles. my wife's ' she is 61 ' is driving back and forth on the interstate to work and home about 50 miles per day. of these 50 miles, 5 is not interstate and secondary surface roads. my mother-in-law is 83 and drives to church, doctor, and store. neither are speeding, driving recklessly or causing more than normal wear and tear on these tires. both vehicles are also garaged when not being driven. in each case, the sidewall was damaged at the exact same location and the damage was identical. a cut in the exact same place about an inch long at a 60-degree angle to the tread. with the first and second tires, i though my wife had possibly hit something. however, after the 4th, that is not possible for all four tires to have the same damage in the exact same place. additionally, i have noticed on several buick forums, a large number of owners with the same problem. i do not know if it is the cold weather or what, but something is wrong. *tr