[MD707]

Pumped up my tyres the other day.
Screen said 'Recommended pressure 2.7 bar.'
Set all 4 tyres to 2.7 bar.
Got in the car and checked the screen, car is happy.
Drove off.
Screen changed. 'Recommended pressure 2.8 bar'.

What's that about?

[StevenDS85]

You have 19 inch? 2.8 bar it is.

[FrostNixon]

Mine is more weird, tyres are at 2.8 but the car shows 3.2 front and 3.3 rear...

[MD707]

Originally Posted by StevenDS85

You have 19 inch? 2.8 bar it is.

Yup 19"s. Confused as to why it changed its mind!

[phayze]

Recommend pressure change with temperature.

[HighlandPete]

Originally Posted by phayze

Recommend pressure change with temperature.

That's the one. After 'teach-in', displays the nominal and optimum pressure, allowing for current temperature.

From BMW:

Unlike the tire pressure sticker, the electronic tire pressure label permanently monitors the nominal pressures taking into consideration the current temperatures. This means that it determines and displays the optimum tire pressure at any temperature.

Much more accurate that the guesswork from a simple cold setting pressure, and the estimated 'allowance' for the working pressure (once a tire is warmed up).