[HeatJoey]

so I got my ps4as' on and now it says tire pressure low, I tried changing the setting in the Idrive however it did not have an option for the tires I got, or anything close actually and now it's showing an error to check pressure. I filled them up based on the printed manual (or very close) but now it says recommended 44 F and 48 R. I have them at 40 and 41.

is there any way to fix the recommended tire pressure? I'll post the pics in the reply as they're in my phone.
thanks,

[HeatJoey]

This…

[HeatJoey]

also, it was ok for the first day and today it changed on it's own somehow...

[dudley@07726]

I’ve never seen tire pressure changes like this. I always followed the recommended tire pressure and kept to it. I never changed it based on temperature. Initially, for the upgraded tire and cooling package, it was recommended to be 39 psi.

[HeatJoey]

I actually figured it out. It’s my sons car so I didn’t have the car before but I went in and selected other tire, than it let me reset the recommended pressure to the pressure it was actually at and it’s fixed. I set them cold to what there book suggested for my tire size and speed rating. There are so many options and different settings in the manual I’ve never seen such confusion actually. My hellcat had one tire pressure recommended In The book and door jam and that was it lol. This car and my x3 have at least 30 different scenarios in the manual for tire pressures lol this is from my x3 but the m340 is the same

[Gaviatrix]

Originally Posted by HeatJoey

This car and my x3 have at least 30 different scenarios in the manual for tire pressures lol this is from my x3 but the m340 is the same

I suppose we should be grateful that they put so much rigour into it!

I still wonder about the accuracy though. I installed a TPMS system on our Land Rover Discovery years ago as it didn't have one, and I found that I needed to comprehensively change the pressures depending on load and heat (bearing in mind I live in Australia and on some of our summer trips the outside temperature was in the mid-to high 40s deg.C/115+ deg.F) and the specific wheel/tyre combinations I was using (18" ATRs or 17" LT rated MTRs). With the LT tyres and an offroad camper trailer, on tarmac roads I would often end up at 4-6 more in the front and 10-12 psi more in the rear tyres than the placarded pressures in order to maintain temperatures at a reasonable level.

My 330i has runflats and I don't have the 'full fat' monitoring system per the M340i so can't comment on temperatures for the G20.

[HeatJoey]

thanks for the comments, however temp. really has nothing to do with any of this as all recommended tire pressures are based on cold PSI.

My confusion is why there are so many different suggested cold psi's lol. just confusing as you have to look up your tires, see which ones and what speed ratings, then they have different psi for over or under 100 mph lol. I don't understand this either, as I will be likely doing both so then what LOL?

yes, I understand as the temp rises so does the PSI but again all recommended PSI for any car or tire is based on cold.

[HeatJoey]

thanks for the comments, however temp. really has nothing to do with any of this as all recommended tire pressures are based on cold PSI.

My confusion is why there are so many different suggested cold psi's lol. just confusing as you have to look up your tires, see which ones and what speed ratings, then they have different psi for over or under 100 mph lol. I don't understand this either, as I will be likely doing both so then what LOL?

yes, I understand as the temp rises so does the PSI but again all recommended PSI for any car or tire is based on cold.

[HighlandPete]

Originally Posted by HeatJoey

yes, I understand as the temp rises so does the PSI but again all recommended PSI for any car or tire is based on cold.

The real time display (if temperature sensing active) will be for the working 'hot' tire pressure. Has caused a lot of confusion for some users. For example, if it is showing "recommended pressure 47 psi", that is the current recommended working pressure, not a cold setting pressure.

[RSnic]

Interestingly, I noticed that in original post, my drive displays recommended tire pressure

I don't have that in MyBMW app (see below); is it because my tires, Michelin Pilot 4, are not "starred"? Car has 11/2022 update

[Gaviatrix]

Originally Posted by RSnic

Interestingly, I noticed that in original post, my drive displays recommended tire pressure

I don't have that in MyBMW app (see below); is it because my tires, Michelin Pilot 4, are not "starred"? Car has 11/2022 update

The star will make no difference at all. It just indicates that the tyre is optimised by Michelin for BMW as part of the OE programme and will have very small variations from a non-optimised tyre. Pressures are shown for a particular wheel/tyre size and type, not any specific manufacturer.