What is the "correct" tyre pressure...

herr bmw

///Member
i dont know bud,have spent alot right now with the accident.

but we will see,might take along weekend break,surprise the wife.
will let you know
 

herr bmw

///Member
will do bud,was actually planning on doing the vdub run down to durban at the end of june,but then the accident.so will have to see
 

msm

Well-known member
Interestingly, I've noticed that BMW increased the overall tyre sizes with the F30 too. Iirc, I saw an f30 with 225/45/18s, as opposed to the E90 which is 225/40/18s.

Hence the increased tyre profile, coupled with reduced pressure is probably one of the factors that is contributing to better ride quality on the newer cars.
 
P

petrivanzyl

Guest
Will inflating it too hard decrease mileage on the tyres?
 

abmi0000

///Member
petrivanzyl said:
Will inflating it too hard decrease mileage on the tyres?

You will wear out the centre first and the shoulders will last longer. The inverse will happen if you run too low. The centre will be concave and not wear down while all the pressure sits on the shoulders.

Common RFT problem cos the wall is so hard, that you don't visually notice the low pressure and the sensors only detect sudden sudden drop or VERY low pressure.

I prefer the sensors in the wheel well but jaaa.
 

Bmw.wp

Active member
17inch wheels i pump 2.3 and 2.7. now with the 18inch i just pump 2.3 and 2.5.? is that correct or must i pump the tyres a lil harder.?

i really am clueless here, please help guys.
 

abmi0000

///Member
Tyre pressure isn't just determined by wheel size. The weight of the car dictates a large portion of this.

What car?
 

Philip Foglar

///Member
Even on my old Corolla, 2 bar was just too soft - 2.2 was ideal. On my E90 I am typically running 2.2 at front and 2.4 at the rear - but bear in mind that I have 17" narrow/wides, otherwise if I recall correctly, the narrows on the rear for that size would have to be 2.6 according to the recommended pressures.

F30 tyre diameter is larger, and they are now using 3rd generation RFT's. Ride is most definitely a lot smoother than that of the E90. Maybe with these newer RFT's they have combined the rigidity of the RFT with the pressure to achieve a harder tyre for the inflated pressure without the common problem that makes the shoulders wear out quicker.

Personally I think 2 bar is still too soft - I would try 2.2 and 2.4 and fill with Nitorgen. And then just keep an eye on the tyre wear - as long as it is even then it's fine.
 

msm

Well-known member
abmi0000 said:
Tyre pressure isn't just determined by wheel size. The weight of the car dictates a large portion of this.

What car?

+1

You'd be amazed by sometimes how "trained" staff at tyre places don't understand the difference between pressure and volume.
 

vylint

New member
I have 16" standard wheels, not sure if the tyres are different when comparing the front and back. From what I can see on that tiny table on the inside of the driver side door (gosh I think I need stronger prescription contacts!), it states 2.1 front and 2.6 back for minimal load. Can this be correct? That feels like a large difference to me.

Also, how does one use the BMW tyre pressure check thing correctly? When I had the tyres checked previously, the pressures were different and low, but I received no warning from the onboard checking system. I have subsequently reset it after the tyres have been checked. I'm wondering if I'm doing something wrong.

Any advice?
:thumbs:
 
Top