[MrFoxy]

Anyone noticed if the recommended tyre pressure changes?

Mine was 38psi front/rear so I did that, then set off and checked, recommended pressure changed *

[pbw]

This is what the app is telling me. As I've only had the car for a couple of days, not sure if there has been an adjustment or not.

[MrFoxy]

Originally Posted by pbw

This is what the app is telling me. As I've only had the car for a couple of days, not sure if there has been an adjustment or not.

Possibly mate, I'll need to do a little digging around and see if something's changed

[Rdurty2]

Answered here:

https://g42.bimmerpost.com/forums/sh....php?t=1928714

My thought is ignore the apps rec pressures as they change for who the hell knows why. Set pressure to what the door jam states and send it.

[MrFoxy]

Originally Posted by Rdurty2

Answered here:

https://g42.bimmerpost.com/forums/sh....php?t=1928714

My thought is ignore the apps rec pressures as they change for who the hell knows why. Set pressure to what the door jam states and send it.

Thanks mate, much appreciated

[MrFoxy]

Originally Posted by Rdurty2

Answered here:

https://g42.bimmerpost.com/forums/sh....php?t=1928714

My thought is ignore the apps rec pressures as they change for who the hell knows why. Set pressure to what the door jam states and send it.

Had a look at the jams mate F/R are two different sizes. Front is 36psi 2x passenger's and rear at 42psi at 4x passenger's! Surly that can't be right, it's just me in the car mostly.

The bigger tyre doesn't give you any pressure's other than 4 passenger's

[RockCrusher]

Originally Posted by MrFoxy

Anyone noticed if the recommended tyre pressure changes?

Mine was 38psi front/rear so I did that, then set off and checked, recommended pressure changed *

Noticed this using the TPMS display.

It appears the recommended tire pressures are adjusted for temperature. As one drives the car the recommended tire pressures increase because the tire temperature is up.

The day after I brought the car home I went around with a good tire pressure gauge and set all 4 tires to the correct pressure. I know from experience to strive to get the gauge needle right on the mark. Otherwise tire pressures can disagree by 1 psi.

[danallxt]

Yes i noticed that myself.
Interesting side note:
Had a set of wheels that a standard pencil type air pressure gauge would not fit well to get a good reading So did some research and bought a nice high quality $40 gauge like ya see the track guys use. The thing is like 2-3 lbs off....I have 4 other pencil gauges, all read fine, this thing is consistently off...went back to cheepo pencil gauge.

[MrFoxy]

Originally Posted by danallxt

Yes i noticed that myself.
Interesting side note:
Had a set of wheels that a standard pencil type air pressure gauge would not fit well to get a good reading So did some research and bought a nice high quality $40 gauge like ya see the track guys use. The thing is like 2-3 lbs off....I have 4 other pencil gauges, all read fine, this thing is consistently off...went back to cheepo pencil gauge.

Originally Posted by RockCrusher

Noticed this using the TPMS display.

It appears the recommended tire pressures are adjusted for temperature. As one drives the car the recommended tire pressures increase because the tire temperature is up.

The day after I brought the car home I went around with a good tire pressure gauge and set all 4 tires to the correct pressure. I know from experience to strive to get the gauge needle right on the mark. Otherwise tire pressures can disagree by 1 psi.

Did a little digging on this.

If you have the Pilot Sport 4s and the car is 2 passenger's with two small kids at times (like me) it's 36psi. F&R

Fully loaded car etc it's 42psi F&R

[RockCrusher]

Originally Posted by danallxt

Yes i noticed that myself.
Interesting side note:
Had a set of wheels that a standard pencil type air pressure gauge would not fit well to get a good reading So did some research and bought a nice high quality $40 gauge like ya see the track guys use. The thing is like 2-3 lbs off....I have 4 other pencil gauges, all read fine, this thing is consistently off...went back to cheepo pencil gauge.

The pencil type air pressure gauge can be real good or lousy. I bought a dial gauge (or 3 or 4) and the two larger ones with the easy to read dial and the ability to capture/hold the reading so I can bring the gauge close to see the reading work very well for me.

[RockCrusher]

Originally Posted by MrFoxy

Did a little digging on this.

If you have the Pilot Sport 4s and the car is 2 passenger's with two small kids at times (like me) it's 36psi. F&R

Fully loaded car etc it's 42psi F&R

My car came with the 19" high performance tires. Can't remember the recommended cold inflation pressures now but I set the tire pressures for what passes for "cold" here in the summer (around 70F) the day after I brought the car home.

I don't have the manual handy nor the car to quickly go out and check what the recommended tire pressures are but I am a believer in getting this info from the tag on the door jam or from the owners manual and making sure the tires are properly inflated.

While I don't know the exact numbers for sure a fully loaded car's tires need more pressure. And for times when the car will be driven at high speed tires pressures almost certainly need to be raised.

[ReallyRadams]

The sticker in the drivers door saids front 35psi and rear 39psi. That is what I’ve been following. Like the post referenced here my app changes the recommended PSI all the think.

[MrFoxy]

Originally Posted by ReallyRadams

The sticker in the drivers door saids front 35psi and rear 39psi. That is what I’ve been following. Like the post referenced here my app changes the recommended PSI all the think.

Depends what tyres you run mate

[MrFoxy]

Anyone getting different pressure's?

Honestly baffled here!!

Driver side F/R are 36psi and passenger is 35 F/R.

I'm over filling the tyres then setting the psi with a proper calibrated track pressure gauge.

Is anyone getting the same problem? My tyres are Pilot Sport 4s and the settings in the door jams are 36psi F/R

[RockCrusher]

Originally Posted by MrFoxy

Anyone getting different pressure's?

Honestly baffled here!!

Driver side F/R are 36psi and passenger is 35 F/R.

I'm over filling the tyres then setting the psi with a proper calibrated track pressure gauge.

Is anyone getting the same problem? My tyres are Pilot Sport 4s and the settings in the door jams are 36psi F/R

It is not uncommon to have one side's tire pressures read a bit higher or lower than the other side. This can happen if the vehicle is parked with the sun shining on the tires on one side of the vehicle with the other side's tires in the shade.

Haven't noticed this with my BMW but with another car tire pressures on one side would go up by a PSI after taking a long sweeping turn at speed.

What I learned from that car and have applied this to every vehicle since with TPMS is to set the tire pressures in the AM after the vehicle has sat overnight without being used.

My SOP is to stop at a tire inflation station -- been some time since I have had a garage and an air compressor -- and over fill the tires some. I note the tire pressure for each tire and give each tire a count of 3 or more seconds of inflation. I vary the count, lowering it if the tire pressure is higher than other tires, or increasing the count if the tire pressure is lower than other tires.

The idea is to have the tires a bit over inflated but strive to get them all over inflated by the same amount.

Then I park the vehicle and the next morning go around the vehicle and adjust tire pressures so they are right.

Even after doing this it is not uncommon once the vehicle is underway to observe tire pressures side to side or front to back being different. My SOP is if the difference is not great -- which if it is can be a sign of a tire having a leak -- to just drive the vehicle. Invariably the slight tire pressure differences will go away and while the pressure will be up -- from the driving -- the pressures will be up the same at each tire.

[LivingInSalt]

Originally Posted by MrFoxy

Anyone getting different pressure's?

Honestly baffled here!!

Driver side F/R are 36psi and passenger is 35 F/R.

I'm over filling the tyres then setting the psi with a proper calibrated track pressure gauge.

Is anyone getting the same problem? My tyres are Pilot Sport 4s and the settings in the door jams are 36psi F/R

What exactly is the problem? 1 psi difference is not an issue

[MrFoxy]

Originally Posted by LivingInSalt

What exactly is the problem? 1 psi difference is not an issue

You really want me to explain the problem after you've read the post?

[MrFoxy]

Originally Posted by RockCrusher

It is not uncommon to have one side's tire pressures read a bit higher or lower than the other side. This can happen if the vehicle is parked with the sun shining on the tires on one side of the vehicle with the other side's tires in the shade.

Haven't noticed this with my BMW but with another car tire pressures on one side would go up by a PSI after taking a long sweeping turn at speed.

What I learned from that car and have applied this to every vehicle since with TPMS is to set the tire pressures in the AM after the vehicle has sat overnight without being used.

My SOP is to stop at a tire inflation station -- been some time since I have had a garage and an air compressor -- and over fill the tires some. I note the tire pressure for each tire and give each tire a count of 3 or more seconds of inflation. I vary the count, lowering it if the tire pressure is higher than other tires, or increasing the count if the tire pressure is lower than other tires.

The idea is to have the tires a bit over inflated but strive to get them all over inflated by the same amount.

Then I park the vehicle and the next morning go around the vehicle and adjust tire pressures so they are right.

Even after doing this it is not uncommon once the vehicle is underway to observe tire pressures side to side or front to back being different. My SOP is if the difference is not great -- which if it is can be a sign of a tire having a leak -- to just drive the vehicle. Invariably the slight tire pressure differences will go away and while the pressure will be up -- from the driving -- the pressures will be up the same at each tire.

Thanks mate much appreciated, I'll give it a try. I get 1psi isn't doing damage etc. just don't get why the pressures aren't bang on with the gauge I'm using. I'll give your SOP a go 🤙🏼

[LivingInSalt]

Originally Posted by MrFoxy

You really want me to explain the problem after you've read the post?

I guess that 1psi difference is really messing up your lap times

[MrFoxy]

Originally Posted by LivingInSalt

I guess that 1psi difference is really messing up your lap times

Another stupid comment 😂. Your on a roll…troll 🖕🏼

[Can’tWait]

Originally Posted by LivingInSalt

What exactly is the problem? 1 psi difference is not an issue

Lol

[Invisiblename]

Originally Posted by mnddd

Yeah that happened often to me lol

Tyre pressure is dependant on external air pressure & temperature. Consequently, the TPMS sensor will send the current internal pressure & temp of a tyre and that will vary dependant on the 2 factors mentioned above; hence your iDrive screen will show the recommended pressures based on this. The MyBMW app just copies those recommendations, it’s not a separate calculation.

In summary, the recommended pressures shown in your app, take into account the external air pressure & tyre temperature.