"It is a very heavy tyre, there is additional cost, fuel consumption is higher because of the very thick sidewalls, and comfort is hampered"

No kidding! Got them back off the car and it was like adding NOS

http://carsguide.news.com.au/story/0...-21822,00.html

 

In the new EVO there is an article with some higher-up engineer at BMW's ///M division regarding the new ///M coupe (Z4). In it he specifically says they ditched the run-flats because of the performance advantage of dropping unsprung weight by going to regular tires.

 

There is an article in the AAA magagine that shows the difference between the Michellin run flats and the others. The article goes on to say that 80% of the car will have run flats by 2007 (I could be off by the % and the year as read the article last night).

I don't know how accurate the numbers are or the descriptions of the RF tire constructions, but if the ture, we may be seeing more RFs on new car soon.

 

Yeah, I'm sure we will be seeing more of them and with hope they will be far better then they are now. Really, putting those back on my car was quite the eye opener for me on how they degrade the handling and ride.

What I do find funny is how BMW always uses safety as a reason for the runflats, but then does not put them on every normal non-M car. Last time I checked they did not, and if safety were really their paramount concern wouldn't they put it on even the base 325?

I'm sure space and cost savings vs the full size spare they had is also a consideration.