Low winter tires

If you have a semi-low car with wider than usual tires, and wish to use it in the winter, you buy tires that probably are less wide than the summer tires. That will also make your car lower.
If your car is say 15cm from the ground, cutting two cm to 13 is not what you want in the winter.

The width 255 is the magic value where for example a 19 inch wheel with 30 profile will be exactly equal to a 255 width 17 inch 40 profile wheel. In other configurations, for example 19/225/30 to 17/225/40, there is a 6 mm difference in diameter, which is about 3mm eight difference.
But chances are that you would have a tire that is not as wide in the winter.
Narrowing the tire will also make it's diameter smaller, even if the profile is the same.

I made a sheet to calculate it for myself on my new car.

Maybe I am the only one with this problem...!