Thanks for your input. It is true that weather conditions, altitude, temperature etc... are to take into consideration. It makes sense to go for consistency between tires fronts and rears (since it seems unfortunately impossible to get accuracy). But, how can I can I know if I am even close to specs when 5 (yes 5
) gauges are off 4 to 7 PSI???
The BMW owner manual is quite specific about which tire pressures should be used according to different speeds and number of passengers.