[ajsalida]

Oh, I see. It does not matter that the old set of tires size vs the new set of tires' size is different. It only matters < 1% within a given set on the car at the same time.

edit: the reason why is you do not want the tires/wheels rolling at different relative rates. Because if you think about it it is all metal fluid and clutches in there and something has to slip/give. Also with ABS, the operating principle works off of sensing different rates of wheel rotation front back or side side, and relieving braking pressure on one wheel (stops it skidding) so it catches up to the other. If the sizes are differnt that screws up the sensors reading of the situation and activation thresholds. Same applies to sending power F/R or side side with the Xdrive system.

So there are two issues, one is excessive wear on hard parts, the other is functional interference.