https://www.cnet.com/roadshow/news/run-flat-tires-pros-cons/

Many new cars these days roll on run-flat tires. These unique tires have a reinforced sidewall that can support the weight of the vehicle even after a total loss of air pressure. This gives you the ability to get to a tire shop or dealership to replace your rubber should you have a blowout. Sounds great in theory, but what actually happens when one of these tires goes flat?

Rewind to last weekend, when the passenger-side rear tire of my 2018 BMW 640i Gran Turismo test car had a brief encounter with a Detroit-style pothole. Normally in this situation, I'd just pull over, get the spare, swap 'em out and be on my way. But the Bimmer, shod in 245/45R19 Pirelli P-Zero run-flat tires, required a different approach.