Thanks for the insight and the link! Yeah typically it is an issue because I am running snows in winter where I try to go cheap, running really old tires. But I get that even if I can ignore pattern differences, I should be more concerned about depth or circumference differences over time. I'm going to closely measure the circumference of the tires and shoot for the 1/4" difference or less, rule. Then I will closely monitor depths and circumferences. The car is on the lift quite often for inspections. I wonder what the original recommendation was from BMW for our cars.
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