Tyre pressures dropped suddenly

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Assuming what @Scandinavian has indicated about not having any guidance in the Manual is true for all Taycans.)
I am not sure this is true for all markets and all owners. I do not have the information in my French hard copy manual, it is not in the good to know app, even if there is a section named Tyre Pressure Tables. The only info is for spare wheel at 61 psi? I rely on the PCM TPMS settings.
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@W1NGE , Yes I do have that info, but that are just the technical dimensions etc. No pressure recommendation in that. I thought there would be pressure info in bars or psi
 

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@W1NGE , Yes I do have that info, but that are just the technical dimensions etc. No pressure recommendation in that. I thought there would be pressure info in bars or psi
Read the text and it refers you to the plate on the car as I mentioned in an earlier post.
 
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So this is where I am now;
Porsche Taycan Tyre pressures dropped suddenly E2E41604-81EA-4A5F-B9FE-0E02086FB4FB
why does the deviation think my tyres are under inflated from what’s on the pillar?

So from what some earlier posts suggest, trust the car - so why is 29/30psi correct?
 


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So this is where I am now;
E2E41604-81EA-4A5F-B9FE-0E02086FB4FB.png
why does the deviation think my tyres are under inflated from what’s on the pillar?

So from what some earlier posts suggest, trust the car - so why is 29/30psi correct?
Remind me + Taycan model, wheel size and tyre type?
 

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Read the text and it refers you to the plate on the car as I mentioned in an earlier post.
I am aware of that but I responded to the comment about the manual for the Cayenne as below. Seems the Cayenne has two pages of information with tyre pressures and wheel combination.

ALSO -- the Owner's Manual for my Cayenne has two pages of recommended pressures, based upon the tire size; type of tire (i.e. summer; A/S; snow; etc.) and number of occupants. There is only one recommendation on the inside of the driver's door, and that is for a fully-occupied vehicle with four people. If I used that recommendation and not what is in the Manual, I would see early / uneven tire wear

Secondly I think it gives an incorrect data if you follow the door sticker, as the OP has upgraded wheels as he has stated. The car might have been delivered with 20 inch wheels and he might have upgraded to 21 inch, OEM or third party. In that case the door sticker is not much help. That is why it would be helpful to have information in the manual that would state which tyre pressure is recommended for different tyre sizes.

But if you have original tyres as the car was delivered you would think Porsche should have it correct. I am not too sure since they made a dogs breakfast of the weights allowed in the Taycan in the beginning. Mix up of lbs and kg.
 
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W1NGE

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I understand - had the same in my Cayennes, Boxster, Macan and Panamera. Still things move on.

The plate on the car corresponds to the tyres and wheels fitted at the factory.

For any change to wheel size or tyre you must use the TPMS utility in the PCM - Tyre selection and loading. This will then give you the deviation to be adjusted to match the wheel size and tyres you now have.

Agree a table would be simpler but the electronic method is easier to maintain and keep up to date.
 


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So this is where I am now;
why does the deviation think my tyres are under inflated from what’s on the pillar?

So from what some earlier posts suggest, trust the car - so why is 29/30psi correct?
I think you stated that you have upgraded tyres? From factory delivery or later?
Is the door plate the same size as your actual tyres?
What tyre size are you having on the car now?
Have you checked that the PCM shows the same tyre size as you actually have on the car?
And that they are correctly stated ie summer or winter?

I am still most puzzled by your comment that the pressure suddenly dropped without any action? That makes no sense at all.
 
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Remind me + Taycan model, wheel size and tyre type?
Taycan base. 20” wheels, 245 and 285 rear. Summer or all season Pirelli tyres, not sure
 

W1NGE

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Taycan base. 20” wheels, 245 and 285 rear. Summer or all season Pirelli tyres, not sure
Ok did you follow the steps above using your PCM and TPM menu?

Do the wheels correspond to the driver plate on the lower part of the door frame - if so, these are the values to use?
 
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Evnoob

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Sorry. To be clear. Everything is as factory supplied.

The pressure drop I kinda moved on from, no answer. A glitch?

But now I’m questioning my whole understanding of what’s correct. The software maths is pretty shaky on other things like “mpg” so perhaps the TPM is the same. Perhaps the dealer never set it to 3.3bar at all. Perhaps they set it neither that nor what it should be, and theTPM just glitch corrected.

In short, despite the trouble and disagreement in finding out just what the tyre pressures should be as specified (and noting that the dealer when questioned may have provided the full load numbers rather than normal to account for that delta) I still can’t be sure what the tpm. Is now telling me.

Right or wrong, are they telling me a delta from some as yet unspecified earlier measurement, or are they telling me an offset from some absolute number specified by the spec it understands which should match the sill plate?

Accounting for small differences in ambient temperature of course.
 

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It’s all in the PCM. Set it up with your wheels, tires, and load setup and the system will provide you with Porsche’s ideal pressure for a balance of road holding, efficiency, wear and feedback.

The door frame sticker is a catch all that’s always *safe* but not optimized. If you’re interested in an optimum pressure, use the system built into the car designed for this purpose. Tune from there if you are in search of further personal optimization.
 
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It’s all in the PCM. Set it up with your wheels, tires, and load setup and the system will provide you with Porsche’s ideal pressure for a balance of road holding, efficiency, wear and feedback.

The door frame sticker is a catch all that’s always *safe* but not optimized. If you’re interested in an optimum pressure, use the system built into the car designed for this purpose. Tune from there if you are in search of further personal optimization.
Thanks. But if that’s true then the car as pictured above is telling me I need to inflate my tyres to 29psi?
 

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Thanks. But if that’s true then the car as pictured above is telling me I need to inflate my tyres to 29psi?
Did you check that the tyre setting in the PCM corresponds to the tyres you actually have on the car?
And the pressure should be at 20 degrees C. For about every 10 degrees lower temperature the pressure would drop by 0.1 bar ( 1.5 psi??)
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