runflats are available. try dunlop web site or type your tyre size into google, of course they are more expensive than other tyres. sometimes no matter how hard you try to watch to not run in a pot hole when doing around 100 mph the guy with the overloaded junk truck dropped i piece of box section about 2 inches long, about 5 minutes before you came along and it rips the sidewall out, it called oh shi i think.
that's my story an i managed to limp home as it was late and i mean late one sat night. i still don't worry though just one of life's little hazards (we must carry a lug wrench and jack for something).