E89 Z4 non run flat tyre pressures.

[DonaldTrump]

Just changed the tyres on my E89 Z4 for non run flats, however I am now unsure of the pressures they should be run at. Fronts are 225-35-19 and the rears are 255-30-19. They are currently inflated to the BMW recommended pressures for the run flats, 35psi front and 40psi rear, this to me seems a little high.

Anyone played around with pressures and could recommend them to me??

[Eddieslofart]

32/36 worked for me on the same size tyres.

335d/330d

[Eddieslofart]

32/36 worked for me on the same size tyres.

335d/330d

[E-bmw]

Doesn't seem particularly high for a heavy car on such wide tyres for me.

[Prinny]

I used 38/41 f/r on Goodyear Eagle F1Asy2, and 35/39 on Michelin PS4 (Goodyear has slightly softer sidewalls). That gave (my opinion) best compromise on dialing out the inherent understeer, while not being too snappy at the rear.

That was on a 35i - I imagine you’d be able to go a bit lower if using a 4-pot & the decreased engine weight.

My rule of thumb on a car desgined for r/f is 3psi more on non r/f to compensate for reduced sidewall stiffness, and then experiment from there.

[DonaldTrump]

I'm going to try 32 front and 37 rear and see how it feels.

[Mach]

I run 33 front and 36 rear on my 35iS. Michelin Pilot Supersports.

Seems to work fine.

HTH

[Herbs]

34 38 is the recommend pressures according to the owners club