BMW have suggested ridiculously high tyre pressures for the M135ix in order to reduce it's emissions. However, this massive over-inflation can lead to central tyre wear (particularly on Bridgestones), poor grip, poor ride quality, tramlining, etc. All bad, basically. The only upside to over-inflation is MPG.
For a lightly loaded F40 M135ix, people have found dropping to roughly 2.5 Bar/36psi front and 2.3 Bar/33psi rear a noticeable improvement (or even slightly lower). Well worth an experiment as air is basically free at your local petrol station.
Tyre pressures should be set cold, using a decent pressure gauge like a RaceX. Don't forget to reset the TPMS to the new pressures afterwards.
For a lightly loaded F40 M135ix, people have found dropping to roughly 2.5 Bar/36psi front and 2.3 Bar/33psi rear a noticeable improvement (or even slightly lower). Well worth an experiment as air is basically free at your local petrol station.
Tyre pressures should be set cold, using a decent pressure gauge like a RaceX. Don't forget to reset the TPMS to the new pressures afterwards.