[relic]

For what it is worth, I switched to non run flats on one of my prior BMWs and found the ride difference very marginal. Since then, with 3 different BMWs, I have stayed with run-flats.

I have also done about 75,000 miles on run-flats (over 3 cars) and during that time I have had two run-flat blow-outs. The first was a piece of glass on a California freeway that took out a rear tire at 70mph on my BMW 335 convertible. I tried to continue at 50mph for 5 miles to a dealer but the tire was so damaged it shredded to bits in less than a mile. A flat-bed tow to the dealer and a replacement tire took just over an hour.

The second was an Illinois pothole that split the whole side of a front tire on my 550 GT. I managed to get it to the side of the road before it became unmovable. In fact I was surprised the rim was not damaged, especially after later finding that it had taken out the wheel bearing. A flat-bed tow to the nearest dealer was the next step and that took 3 days as the incident happened on a Friday night and I did not want the different (Bridgestone) 20” tire that the dealer had in stock. I bought the GT with summer performance Pirelli P Zeros and had a replacement tire delivered overnight from Tire Rack.

Before raking a 6000 mile trip from Chicago to Florida with return via Philadelphia I bought a set of 19” rims with winter (Bridgestone Blizzak) non-run-flat tires. I only did this because I could not obtain suitable winter run-flat tires at the time. While I struck the expected heavy snow that made me glad I had not tried the trip on the summer tires, most of the driving was in sunny Florida at speeds averaging over 70mph. The winter tires gave a slightly harsher ride and were also noticeably nosier, especially at 80mph.

With the long distances involved on that trip I briefly considered taking a spare but felt that took up far too much space plus the likelihood of a tire failure was very low – and the worst case might be an overnight stay somewhere. Since that trip, and refitting of my 20” run flats I have done completed 3 more drives to Washington DC, including one that included Boston – all with no trouble.

As added insurance I always carry an M series tire repair kit (pump and minor leak sealer) but have never had occasion to use it other than as a great ‘add a pound tool’. I have no concerns driving long distances without a spare, as long as I have roadside assistance available.

In my experience the ride differences are due to the different tires and pressure selection rather than whether they are run-flats or not.