[dchantry]

I bought my E91 Msport yesterday and its fitted with aftermarket alloys both running 235/35/19.

As these are non OEM, I was wondering what recommended tyre pressures people would recommend
34F?
36R?

[Aragorn30d]

36 all round will be fine. Maybe even a bit more.

[dchantry]

Originally Posted by Aragorn30d

36 all round will be fine. Maybe even a bit more.

Thank you

[Digitalize]

I've always felt tyre size doesn't directly relate to tyre pressure. As pressure is not linked to a volume. So you don't need less pressure for a smaller tyre, but you do need a smaller volume of air.

I personally run 45 on the back and 40 on the fronts with standard tyre sizes. Firms up the ride a little after getting rid of RFTs.

[djgandy]

Whatever the door card says.

[dchantry]

They are non standard size so they aren't in the door label.

[Digitalize]

As said, that doesn't matter. PSI is relative.

[old grey steve]

I've found to a degree you have to experiment, using the info inside the door is OK for std RFT's if you're working with non RFT's which I assume you are you'll IMO need to increase the presures a little you might have to have a go and play with the pressures you use say over a feew weeks to find a happyish balance. The teltale sigh over a period of driving is how the tyres are wearing.

Usually if you find the inner and outer tread is wearing faster than the centre section you've underinflated, like wise if you are finding the tyre centres are wearing rather rapidly yet the inner/outer sections of the tyres seem to be holding up then you've overinflated.

THe key is finding the acceptable compromise where the car rides, handles OK yet tyre wear is perfectly manageable.

[acerboo]

tyre manufacture should have chart to show correct pressures

[BarrySt]

I checked RFT versus non-RFT pressures with BMW UK and they said "same pressure whether RFT or not."

[Digitalize]

Well yes, but it depends on the feel you want.

[sparkymarky]

What digitalize said. I run 34f 37r on 235 35 19 and 265/30/19. Anymore and its too hard. And even at this pressure they seem to wear more in the middle than outers (over inflation sign). Doesn't seem to match with the guys running 37f and 39 or 40+ rears but it feels forgiving whilst still no understeer/sagging at these pressures.