Tyre Pressures for 2004 BMW Compact

There should be a sticker on the rear of the driver's roor aperture giving the pressures for different tyre sizes etc.

BMW's reccommended pressures are always on the soft side, to give the most comfortable ride without totally ruining handling and steering response.  That does not mean that they are the optimum pressures, and even then are only for use with BMW-approved (and therefore tested) tyres.  Different tyres and/or drivers who want better handling often require different pressures.  Tyre pressures are not written in stone.

As a reasonable guide I would suggest 2.2 to 2.5 bars all round, 2.5 being the pressures which I have been using on my Z3 for ages, having found by increasing the pressures in small increments that this eliminated understeer and so provided the best steering response. My daughter also found a similar improvement when running her 325 E46 Coupe at 2.5 all round.




Edited by Mike Fishwick - 09 Oct 2013 at 2:47pm

Hi
2.2 bars on the tyre pressures is about 32psi & 2.5 bars is about 36psi
Hope this helps

Rich

Sorry - I had assumed that everyone except myself now thought in Bars!  Being of the old school I find the conversion to be automatic, having been brought up on ships systems where the pressure guages were a mixture of PSI and Bar calibrations - not to mention kilograms per square centimetre.

In the Good Old Days normal atmospheric pressure was held to be 14.8 pounds per square inch, otherwise known as one atmosphere.

Since metrification and the SI system of measurement, it is now called a Bar (as in barometric pressure) so if you regard a bar as being 15 psi you will  not be far out.

It is worth training yourself to think in Bars, as most modern pressure guages are calibrated in Bars - except in the United States, where they remain addicted to the imperial system - although they would never call it that!  Even so, some traditional American things such as the .38 pistol ammunition is actually .36, or to be exact .357 . . . or 9 mm!  This is why a .357 Magnum pistol will happily fire .38 ammunition.  Likewise, the US quart is 956 cc, or almost a litre.


Edited by Mike Fishwick - 10 Oct 2013 at 1:05pm