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      10-14-2020, 09:35 AM   #3

Drives: '15 650i Convertible
Join Date: Apr 2018
Location: US

iTrader: (0)

Originally Posted by Frupal View Post
How sensitive are these cars to tread depth differential on the same axel? I ask because I may need to replace one (or both?) rear tires due to a patch that I think is leaking. The tires have about 18k miles. Michelin A/S 3+.
I tried to research this in a fair amount of depth once, although not necessarily for this car. It's rather confusing and seems to be largely theoretical. What you won't find is examples of people saying "my car suffered a major failure and I was told it was because my tires sizes were too far off." Nonetheless, the drivetrain is supposedly unduly strained because the different diameter tires tires rotate a different number of times per mile. Car makers have different recommendations, with 2/32" difference on the low side and 4/32" on the high side. A new tire is about 11/32" tread depth and a worn out tire is about 3/32" in depth. So if you are at 5/32" on one side, a new tire is probably too much on the other side.