Run flats or not...

[190]

If the suspension is designed/tuned to use wheels shod with run-flats going to 'normal' tyres might be detrimental to the ride and handling?

Tyres are an integral part of the suspension system and effectively what you have is two springs in series. When you have two springs in series the resulting overall rate is always lower than either of the individual springs. While it's possible that it is detrimental to both ride and handling it's more likely to just move the bias in the direction of improved low speed ride. While normal tyres undoubtable did that to a very noticeable extent on the early BMW's with run flats it should still do so on the better tuned more recent models, even if it's a less obvious improvement.

If we knew the relative spring rates of normal tyres vs run flats it would be possible to calculate the impact on overall spring rate. For two springs in series the overall spring rate is:

(Spring 1 times Spring 2) divided by ( Spring 1 + Spring 2)

 

[350cls]

Are Run Flat Tires Worth the Investment?

 

[Ahmedb]

I'm a fan of non runflats, especially on more performance orientated cars. From my experience, the pro's are they are cheaper to buy, quieter, lighter, offer more performance and are slightly more economical. You lose the security of being able to run on flat though with potentially no spare

 

[PeeTee]

Used to always buy ContiSport run flats. I've since changed to Michelin PS4. Do not regret it one bit

 

[carraig]

I wish I had of got them

 

[Deleted member 6183]

I wish I had of got them

View attachment 90491

In nearly 40 years of motoring I never had one of those.

 

[bootsboy121]

i heard it invalidates insurance if your ever in an accident.

if manufactuers say it was manufactured with run flats they always need to be used.
not sure how much truth there is in that?

 

[markjay]

i heard it invalidates insurance if your ever in an accident.

if manufactuers say it was manufactured with run flats they always need to be used.
not sure how much truth there is in that?

When you declare the change to your insurer... you'll find out.

 

[Deleted member 37751]

if manufactuers say it was manufactured with run flats they always need to be used.

If they went down that route, any car on the road that didn’t use the OM tyres recommended by the manufacturers would make a lot of cars uninsurable.