[E92Fan]

The difference in pressure requirements is probably due to the suspension damping and rebound settings being different front to rear...

[NFS]

Originally Posted by Cafe.Racer

Wider rears?

The wieght distribution is whatever it is - a pressure difference between front and rear can't alter where the centre of gravity is.

However - as you say - it does have an affect on the traction between the tyes and the road .. i.e. the contact patch.

With mixed tyres the rears are wider so they have more 'grip' than the fronts. This will lead to understeer, so increased pressures help balance that out and make the handling more neutral.

Even where the tyres are of similar sizes the BMW chassis is biased toward understeer, so a bit of extra pressure in the rears helps to defeat this.