Tyre Pressures Macan GTS, 21 inch, P0’s

[GB_Macan_GTS]

Bit of a generic question here. I recently set my tyre pressures to the levels shown on the panel inside the drivers door. I set them on cold tyres ( left overnight ) on my drive. I have a digital and a manual pressure gauge and both showed the same pressures. When I the drive the car the app is showing between +4 and +6 on the tyres. I assume this is indicating the tyres are over inflated by upto 6 PSI.

I understand tyre pressures increase as the tyres temps rise, but should I just stick with the pressures when cold, or adjust the tyre pressures as the app recommends? If its the former, then is there really any relevance to the pressures shown in the app?

 

[6DW]

It is possible to set the TPS system on the vehicle display to either Full Load or Part Load….. This needs to be set to correspond to the actual tyre pressures you inflated your tyres to. That way the system and your selection are in line.

It could be that you have set actual pressure to Heavy Load and the system is set to Light Load, therefore showing the tyres are over inflated..

Hope this helps
David.

 

[GB_Macan_GTS]

Thanks for that. Somewhat embarrassingly, having owned the car since Nov, and a Gen 3 Macan S for just under 3 years prior to that, I didn’t know there was an option to change that lot

That said, it is set correctly. I just re-checked the tyre pressures manually too, and they are to the required spec.

I suspect the issue is the app. Tyre pressures should be taken cold, and the display in the car shows values above 15mph. I don’t know when the app takes its reading. If its after i’ve been driving the car for a while then presumably the tyre pressures will be above the recommended levels because they increase with heat, right? I believe that’s why you’re supposed to measure them when they are cold.

Thanks for the info though. Always good to learn something new about the car.

 

[6DW]

Just another thought, as well as the onboard app showing the pressure ‘deviation’, I believe it can also show the actual pressure on each wheel. It would be interesting to compare the actual app readings with your tyre pressure gauges ……

 

[GB_Macan_GTS]

thanks. The screen in the car shows the actual pressures, but i don’t think the app does. I guess the question really all boils-down to if I should set the tyre pressures to the setting detailed on the door panel when the car is cold and just ignore everything else. The pressure will go up anyway as I drive, so I guess I should probably ignore that and only worry about any significant differences on individual tyres. Its possible I’m overthink this.

 

[GB_Macan_GTS]

just checked and I can’t find a way of showing actual pressures on the app, but currently its showing a variance of +0.3 bar on all four wheels ( at least its consistent ). I guess the question is if that variance is just because the app is taking the reading from the end of my journey rather than the beginnin, when the tyres were cold

 

[Lancerlot]

Porsche suggest tyre pressures should be adjusted during an ambient temperature of around 20 degrees C. So unless you have a heated garage, this might prove difficult at this time of year and you may need to make adjustments taking this into account.

Personally, I always set my TPM to BAR readings not PSI and regard them as a guide only - useful for monitoring air loss or punctures, but not much else IMHO. Tyre pressures can vary considerably over the course of a journey. More constant results are obtainable by filling tyres with nitrogen or dry air.

The best way to check tyre pressures is manually, using a calibrated hand-held dial gauge.

Regards,

Clive

 

[Neil1911]

GB, it's a minefield isn't it? I know exactly how you feel, bern there! I now trust the TPMS to accurately measure the pressures taking correct account of the ambient environmental temperature and pressure so that I can just adjust the tyres in line with the recommendation in the MFD but, only after monitoring for a few days and decent mileage. This link will be of interest and if you search further in the Macan.co.uk forum you'll find acres more on the subject!

21” wheel tyre pressure - Page 2

21” wheel tyre pressure - Page 2 Wheels, Tyres, Suspension, Chassis, Issues and Fixes - Porsche Macan Forums

www.macanforums.co.uk

 

[GB_Macan_GTS]

thanks all. I think it sounds best that I measure using the manual pressure gauge and just use the app and the TPMS to see if there are any significant deviations tyre to tyre. One last question; if I am measuring the tyre pressures in 70 million degrees below zero ( i don’t have a garage, and its been a tad nippy recently ), what allowance should I make i.e. should I inflate above or below the recommended pressures?

 

[Neil1911]

That's a calculation that's beyond me, needs an MSc in the relevant physics discipline and one of the reasons I've adopted the approach above, using this screen.....

 

[Lancerlot]

what allowance should I make i.e. should I inflate above or below the recommended pressures?

Depends upon your intended use. If you're going to be undertaking short journeys, it is unlikely the tyres will warm up sufficiently to radically alter pressures. Longer journeys may result in higher tyre pressures that will need adjusting.
Suggest you inflate to the recommended pressures all round, then monitor and adjust according to use.
BTW - Macan tyre wear is usually quite even, so if you experience any uneven tread wear, it may be worth having the chassis setup checked out.

Regards,

Clive