Non Runflat Tyre Pressures

[sammyz]

I fitted non run flats last year and left the tyre pressures lower than for the run flats at the garages suggestion as they were 'not run flats'.
When really pushing the car towards its limits I thought the tyres- Uniroyals- 'squirmed' about and so I adjusted the pressures up to the correct BMW run flat settings.
The car now feels much more planted and the 'squirming' has gone.
So I think, in the case of the 35I I certainly would recommend sticking to the BMW pressures in the first instance and adjust to suit from there.

 

[R.E92]

I'm not surprised the car squirms with Uniroyal tyres

 

[jimbo1958]

I found that running the stock pressures makes the car feel unsettled.
I now run 40 rear and 34 front. Best for both the PSS and PS4S. Nice even wear too.

Almost the same here. 40 rear and 36 front on PSS.

 

[mcbutler]

One of the reason manufacturers produce reinforced tyres Michelin Pilot Sport 4 for example is specifically to allow for higher pressures when replacing run-flats.
The word load does not always mean vehicle weight, it can be internal loading from pressure also.
Part of the reason the tyre pressures are so high is the width of the tyre. In order to maintain equal road contact 12 - 15 cm from the tyre wall the high pressure is needed. It also maintains the tyres shape at high speed when the tyre is prone to bulge (however slight) in the centre of the tread.

I run PS 4 all round on my Zee, they are fabulous, sticky, quiet and well worthy of the rave reviews they get. Highly recommended.

I got fronts for £86 each with delivery from blackcircles.com