Quote:
Originally Posted by GS - X3
Perhaps BMW is specifically referring to the relatively new designation of "All Weather" tires vs. the more traditional "All Season". All Weather tires differ from All Season tires in that they qualify for the "Snowflake" designation on the sidewall, making them a true "Snow Tire" that also offers All Season capabilities, and a longer tread life than traditional "Winter" tires.
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You may be onto something here. Here is the warning in my 2021 manual from page 295.
"If the vehicle is equipped with an M Sport differential
and all-weather tires on 19 inch rims,
this can alter handling, for instance the vehicle
may swerve off course. There may be a risk of
accident or risk of damage to property. If the
vehicle is equipped with an M Sport differential,
do not fit all-weather tires on 19 inch rims."
The term "all-weather" is specifically used. From a superficial search on the internet (why didn't I know this already?) the following distinction is presented: "All-weather tires are distinguished by the unique 3-peak mountain snowflake pictogram on the sidewalls which indicates that the tire has at least 110% the traction of a standard all-season tire (for the curious, the standard used is ASTM E1136-14)." My Michelin Pilot Sport All Season 4s do not have that 3-peak symbol, but I already knew that. What I was doing was conflating the two terms "all season" and "all weather," and it appears that is not accurate.
This does not make my driving impression reported earlier go away, but it seems to indicate the manual warning does not necessarily apply to all season tires, but only to all weather tires.
This does mess with my follow-on plans to get Falken Wildpeak A/T tires, because they are definitely all-weather tires. But maybe I'm home free because I was going to mount them on 18" rims.
I'll take a guess that if the warning applies to 19" rims, it would be more so with 18". I wonder.
This seems to be a problem for those of us with M Sport Differential, with what I believe is a common practice: going to a smaller wheel and a "higher" aspect ratio tire for winter and all-terrain use. It would seem to mean that to make the car handling "safe," I would have to go with a 20" wheel, which is exactly the opposite from the common practice.