[Petem95]

Ok I'm sure this has been covered before, but I can't find a definitive answer!

What is the correct tyre pressure in psi for front/rear tyres on an e90 M-Sport with 18" MV3's on runflats??

I'm currently running at 30psi all round..

Thanks

[F31-340i]

It gives the pressures on the drivers door for different loads - in bar.

Google "bar-psi converter" - et voila!

[TMP]

yep on drivers door - from memory isnt it 2.7 front, 2.9 back?

my pump thingie does bar, so dont know psi.

[zltm089]

30psi seems a bit low....i might be wrong....

I'm on 18 inch wheels aswell.....I use 38psi for fronts and 40psi for rear.....i like them a little bit over inflated....

[Petem95]

Originally Posted by TMP

yep on drivers door - from memory isnt it 2.7 front, 2.9 back?

my pump thingie does bar, so dont know psi.

That's basically 39/42psi which sounds a bit high to me, but then maybe runflats should be run at a higher pressure?

I'll check on the door sticker tomorrow anyway!

[F31-340i]

Yes they are high - but run them low at your peril - I think that is one of the contributory factors in the cracked wheels fiasco. Underinflation puts more of the cars weight directly on the sidewall - which can't be good for the inner rear rim edges.

[mjh93sa]

It's only when you do the conversion that you realise how high the pressures are. But as said, they do need to be this high.

From many reports it seems that running at lower pressures also dramatically increases the wear rate. Mine are set mid-way between light and full load and have exhibited even wear. and decent lifetime.

[F31-340i]

further observation: I run 19"s which have even higher pressure specs according to the door (E91s do have the correct figures for 19" wheels/RFTs even though they are not an option).

I found that even when going from slightly underinflated tyres to correct (but very high) pressures, the ride didn't actually change that much in terms of harshness - it just felt more "correct" & surefooted at the higher pressures. Hence I don't think there is any point in trying to run the pressures "low" to improve the ride - I'm not sure it works that way with ultra low profile RFTs.

[Matt2008]

When i bought my 335d from the dealer i upgraded to 19" 269 performance wheels with Bridestone Potenza runflats. Whether the pressure charts inside doors are now relevent because of non standard wheels i have no idea but the BMW dealer fitted the new wheels before i picked up the car.

I took a reading of the pressures for reference on day 3 of owning and all 4 tyres were bang on 3 bar (43.51 psi).

I thought that was high but keep them at this because of any wheel cracking issues and thats what the dealer supplied them at.

It does state on the tyres that 50psi is max.

[foxy-367]

Tyres always have a max rating as they can go on any car. On mine I add 0.1 bar so run the front at 2.3 (33psi I think) and rear at 2.6 (38psi I think) door pillar says 2.2 and 2.5 respectively FYI I'm on 18" wheels and tyres

[SiKkBaSs]

I did the old putting the fronts at less pressure than the rears, but then it got cold and I got a RFT warning sign and thought fack it. So I inflated all tyres to 35psi.