Spare Tire Size question

[boX5]

I just got this spare from Bimmerzone today, and it fits perfect in the storage area which is carpeted.

My stock tire was 255/50/19 runflat which I upgraded to 265/50/19 non runflat. The difference in riding comfort and handling is so much better.
The car feels so much more stable on highways.

Now, the question is I saw two different spare tire options
BimmerZone 155/90/18, identical size to stock 255/50/19 but 1.4% smaller in diameter than 265/50/19
ECS Tuning 165/90/18, 1% larger than 265/50/19

As the tires on the car wear and spare staying the same, size difference for both options will be more like 1.2% off - plus and minus.

I want to hear from anyone who actually had to use a spare that was slightly over 1% off in size with xDrive

It it ever gets used, it will be for temporary shot distance driving.

Searching online, I did not find any info specific to xDrive and from real life experience.

I do see few mentioning 1% rule.
Thanks in advance.

[spit]

that's true, I've thought about that too. It was because of this mismatched 1% that I gave up the spare wheel.
Especially since I currently have 612m staggered

[happydude]

I have the 19” spare because I have the MPBK and it is the one needed to clear the calipers. Had no issues with comfort when I had a flat, but it was only on for about 10-15 miles to get me home and then to tire shop the next day. For reference I run staggered 469m 275/40/20 and 315/35/20