I have personally carried out safety tests involving blowouts of these
tyres at 80mph while cornering. I have also been in the great danger of replacing an offside rear wheel with a blown out conventional tyre on a motorway hard shoulder. Because of their stiffer sidewalls, runflats generally have the ride quality of the next lower profile, by which I mean a runflat 245/45 R17 will feel more like a conventional 245/40 R18. Ride quality can be shocking on 19” or 20” wheels