Definitely need the spare. I bought mine for about 60% discount. With 70% tread

It cost me $105 with shipping and $20 to have a local muffler shop to install after the blow out that killed the tire.

When the valve stem blew out it was free for Sam's club to repair as well as twice I had a screw get into my tire that was repaired for free.

Non run flat will self destruct just the same as run on flat should you drive on them. With run on flat you can drive a little ways without any damage which has helped me a few times where I drove a little bit in the city with no damage. One time I actually removed the screw that caused the damage and put in a different flat head screw that let me drive to Sam's club to repair the tire without even changing to the spare. Fortunately I always have my tire pump in my car

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)