I bought a compact spare soon after purchasing in Feb. 2020 which fits into the space under the floor in the hatchback area. Run flats usually don't give a smooth ride but have probably improved since I had them 10+ years ago... There is a thread on what compact spare to buy and how it gets installed in the car. It's really easy and gives peace of mind!
I had run-flat tires on my last car before my Niro EV. They gave a pretty rough ride and were pretty noisy. They also added a lot of weight to the car. Despite the noise and rough ride, though, the additional weight would be my biggest concern on the Niro. I'm guessing it would have a noticeable negative impact on range.
Go to any BMW/Mini forum and ask what owners think about run flat tires. Most BMW products come equipped with them, and the ride is so harsh that lots of owners can't wait to dump them. Some hate them so much that they replace them immediately after taking delivery of their new car. That being said, slowly but surely runflat tech seems to be improving on this issue.
I commute in my Kia Soul EV about 40 miles daily. 100% charge uses about 30% round trip. Decided to get run-flat tires after 2 punctures. The run-flats have an impact of about 5%. This means it takes a couple more hours to charge but the peace of mind is worth it. What I don’t understand is if over inflating or under inflating would have a positive impact. If anyone knows, please reply. Sent from my iPhone using Inside EVs