[Rob_G77]

How does the 8 series monitor tire pressure? Are there sensors in the wheels or does it measure by wheel rotation?

Rob

[Beemer5to3]

There’s TPMS sensors on the valves on the inside.

[Seaford]

Shortest Q&A ever!!

[AP]

Yeh tpms is as described above. TPWS ( tyre pressure warning system) is the lesser system that uses the abs sensors to detect a wheel running at a different speed and hence not at the right pressure or deflated.

[Wavy]

Audis measure by rotation. I hate those systems.

[Qsilver7]

It depends…since the OP is from Canada…the TPMS system (option 2VB) is not required…they can have the FTM system in Canada. Post a pic of your Vehicle Status screen that shows which tire monitoring system you have.

If it says something like TPM/RDC at the bottom of the screen…then you have the TPMS system which has sensors in each wheel.

If you pull up the tire monitor screen in iDrive and it says something like FTM/RPA…then you have the flat tire system which uses tire rotation to determine if a tire has low pressure.

TPM/RDC = SENSORS
FTM/RPA= NO SENSORS

[Moopai]

Tw questions since we are talking tire pressure. I noticed the BMW app as well as the iDrive gives tire pressure recommendations for front and rear which are higher than what's on the driver side door. The label on the car for M850 states 42 PSI front / 44 PSI rear. What tire pressure should one have? The second question, what is the reason for the M850 to have a lower tire profile than the M8C? I noticed all M8C are 35s front/back vs 30s for the M850. Thanks

Originally Posted by Qsilver7

It depends…since the OP is from Canada…the TPMS system (option 2VB) is not required…they can have the FTM system in Canada. Post a pic of your Vehicle Status screen that shows which tire monitoring system you have.

If it says something like TPM/RDC at the bottom of the screen…then you have the TPMS system which has sensors in each wheel.

If you pull up the tire monitor screen in iDrive and it says something like FTM/RPA…then you have the flat tire system which uses tire rotation to determine if a tire has low pressure.

TPM/RDC = SENSORS
FTM/RPA= NO SENSORS

[Qsilver7]

The tire pressure chart on the door jamb is for COLD tire pressure reading (tires have not been warmed up by driving/rotating/etc). The iDrive chart takes into account that the tires have been rotating...thus heating up and adjust the suggested PSI accordingly.

[bloozemanAZ]

Originally Posted by Qsilver7

The tire pressure chart on the door jamb is for COLD tire pressure reading (tires have not been warmed up by driving/rotating/etc). The iDrive chart takes into account that the tires have been rotating...thus heating up and adjust the suggested PSI accordingly.

Interesting as my experience is somewhat opposite. The iD7 tire pressure screen from my experience is controlled by the tire setting. Discovered this as the VPC had chose custom and although the right tire size it whacked out the recommendation to an absurdly high pressure. On the summer tires setting (default OEM sizing displayed) and less than 100MPH it matches the door jamb. Change it to greater than 100MPH and they go up by 4lbs respectively for front and rear if memory serves.

Before going on a performance drive in which I'll hit over 100MPH I'll always check to ensure the tires have properly heated up and at the iD7 recommended pressure before doing so.

Yep, going to have to get the compressor out tomorrow for some inflammation on the front and rear left tires while cold.👍

[Moopai]

I do understand how they tire pressure changes between cold and warm. My question is why the iDrive at times recommends higher value even when the tires are warmed up? As an example, the door jamb specifies 42 front/44 back when tires are cold. Once you start driving and the tires warm up the front might go up to 43 or 44 and the rear for 45 or 46, iDrive would recommend higher numbers than the actual temperature which doesn't make sense! I will take a picture to show you what's happening.

Originally Posted by Qsilver7

The tire pressure chart on the door jamb is for COLD tire pressure reading (tires have not been warmed up by driving/rotating/etc). The iDrive chart takes into account that the tires have been rotating...thus heating up and adjust the suggested PSI accordingly.

[AP]

Ambient temperatures . So even if the tyres are “cold” ie the car has been sitting still for a reasonable length of time, the ambient temps will have a bearing on matters

So if the weather suddenly gets cold, you may see the pressures in your tyres being a little lower than previously and need increasing a bit

I have a shortcut button that points to tyre pressures so I can keep an eye on it every journey and should the weather change significantly I know that I’ll probably have to make an adjustment to the pressures.

[Rob_G77]

Originally Posted by AP

I have a shortcut button that points to tyre pressures so I can keep an eye on it every journey and should the weather change significantly I know that I’ll probably have to make an adjustment to the pressures.

I always have button 1 set for showing my tire pressure.

BMW voice recognition doesn't seem to have a command to directly show tire pressure. The best I could do was get to tire settings where it asked if I wanted to see tire pressure and temperatures and I would have to reply "yes".

Rob

[Moopai]

Sure it does, ask BMW for tire pressure, it will bring the screen up with the info. That's how I check it every time.

Originally Posted by Rob_G77

I always have button 1 set for showing my tire pressure.

BMW voice recognition doesn't seem to have a command to directly show tire pressure. The best I could do was get to tire settings where it asked if I wanted to see tire pressure and temperatures and I would have to reply "yes".

Rob

[Rob_G77]

Originally Posted by Moopai

Sure it does, ask BMW for tire pressure, it will bring the screen up with the info. That's how I check it every time.

I do and it just tells me it's all ok, but then asks if I want to see the pressure and tempeature. ID7 language interpertation can be spotty though and mabye one word I am saying is throwing it off.

Rob