Sidewall Aspect ratio for winter: 40 or 45?

[aboulfad]

I've read and I've searched enough but I can't conclude if there's any winter handling performance difference with a different sidewall height, let's say between a winter tire 245/45R18 and 245/40R18?

A difference is that the sidewall is longer on the 45, would that mean it's better handling for deeper snow? And I guess the cars handling could be more "soft"?

I know it's not winter yet, but an used OEM 640M offer is available so I need to decide on the ContiWinter (255/40R18) soon or an aftermarket set much later when winter arrives.

[IND-Distribution]

I would suggest doing what's possible to respect the factory rolling diameter- use a tire who's width and sidewall height get you as close to the original BMW front and rear rolling diameters as possible. The actual height of the tire won't be as important as the wheel speed calibrations related to ABS and traction control.

[remmib]

Tire size for the OEM M3 winter are 255/40/18 or 255/35/19, so 245/40/18 migth be on the small side.

[aboulfad]

Lots of forum winter drivers are running 245... My question was the difference if any between the two aspect ratios in winter handling.

The more I read, and depending on the severity of winter and road conditions, I think a taller sidewalk may be more advantageous but not sure. Thanks.