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On the subject of tyre pressures I thought that the label on the inside of the fuel filler cap stated 2.5 bar (~36 psi) though I noticed that my VW dealer gave me 39 psi when I recently had new tyres.
Perhaps he was taking into account those big APs !!

But seriously though, the latest advice from the actual tyre manufacturers is to actually run on the 'fully loaded' pressures at all times, even when just one person is in the car. This is to help reduce rolling resistance, and therefore improve not only fuel economy, but also the generall 'efficiency' of getting maximum efficiency from the engine and brakes.
So wouldn't 40+ psi result in uneven tread wear?
No. Modern quality radial tyres which use steel belting in the tread plies won't really 'baloon' from being over inflated. Obviously, if the plies are damaged, then increasing the pressure will noticeably show up worse - but for normal 'healthy' tyres, there is absolutely no problem with over-inflation.

But under-inflation - well that is a very different issue.
