Tyre pressures all reading low

[Regulo]

Got in the car this morning and got a low pressure warning. All 4 tyres reading 39 psi. When I last looked they were all 42. I understand the lower ambient temperature will drop the tyre pressures, but I checked them using the display on the inflator pump, and they all show as 41 after a 15 minute drive, the car still showing 39. Previously the two readings have been corresponding. What's going on?

 

[M1tch]

Is it a digital gauge you’re using? Also after 15 mins there is potentially enough heat generated to change the pressure. The TPMS modules sleep after a certain time and take a few mins to wake up to save battery life. Also as you say it’s all likely due to temperature drops outside.

I would pump them up to the correct pressure when cold and see how you get on. Highly unlikely to have 4 flats at once.

 

[TM3P1]

If it helps mine have done exactly the same thing since the cold spell. Will pump them up tomorrow and see how it goes!

 

[Cloggie]

It's just the lower outside temperature, no big deal. Just inflate a couple of bars and all good.

 

[Andy H]

Same here. I think this will be the 3rd top up in a year.

 

[Regulo]

Thing is, it didn't happen in the last 2 autumns as it got colder. Is there a recalibration to be done?

 

[MrBadger]

Yay. As predicted to the day…

it’s hard to really know this time of year with large variation in temperature tyres (cue posts with ‘tyre pressure warnings has gone off’)

Seriously though, I do have one tyre behaving a little like OP is describing. TeslaFi is showing a sudden change in that tyres pressure a few minutes into the drive after which everything stabilises and all is good again. I suspect that that is the point that TPMS gets its first true readings but it’s a bit more nuanced than that.

I think the change is that previously would show no pressure reading at start of a drive until it got its first updates, but now it displays the last pressure readings previously recorded, ie potentially from previous drive. Hence sudden jump between initial stale readings and fresh readings for the drive.


RR increase 1psi in space of a minute. Return leg of two very short drives. Out leg was stable and approx 10 mins before. (time top to bottom).


And out leg 10 mins before

 

[MrT3]

Thing is, it didn't happen in the last 2 autumns as it got colder. Is there a recalibration to be done?

It just depends how low your tyres were below the recommended 42 PSI before the quite dramatic fall in temperature in the South over the last few days has lowered our tyre pressures. Nothing to worry about and there isn't an option anymore to recalibrate - Tesla fix the required pressure to be 42 PSI and a 10% fall to just under 38 PSI will trigger the alert.

As tyres will naturally lose pressure over time I just suspect your pressures were higher last year compared to this year.

Just inflate a couple of bars and all good.

Hopefully most people won't need an extra 29 PSI adding - a couple of 1/10ths of a bar should do

 

[Roy Batty]

Mine all popped up with a warning, they were on 41PSI give or take before the cold spell and dropped to 39PSI.

Topped them all up on Saturday so hopefully won't need to do that again.

I would imagine most people just wouldn't have noticed before TPMS turned up.

 

[GRiLLA]

Same message, I've had to top them up when it gets colder every year, damn physics.

Maybe you've had them over inflated previously.

 

[Andywil]

Yay. As predicted to the day…



Seriously though, I do have one tyre behaving a little like OP is describing. TeslaFi is showing a sudden change in that tyres pressure a few minutes into the drive after which everything stabilises and all is good again. I suspect that that is the point that TPMS gets its first true readings but it’s a bit more nuanced than that.

I think the change is that previously would show no pressure reading at start of a drive until it got its first updates, but now it displays the last pressure readings previously recorded, ie potentially from previous drive. Hence sudden jump between initial stale readings and fresh readings for the drive.


RR increase 1psi in space of a minute. Return leg of two very short drives. Out leg was stable and approx 10 mins before. (time top to bottom).
View attachment 982496

And out leg 10 mins before
View attachment 982497

Teslafi can only get the readings when the car is moving as that is the only time the TPS is active, therefore the resting pressure will always be the pressure when last driven.
The next drive the pressure will probably be lower at the start as the tyres have cooled.

 

[Regulo]

Thanks for putting my mind to rest. If I adjust the pressure to be correct now, won't they be over pressure come spring? I presume we don't get over pressure warnings?

 

[init6]

Yay. As predicted to the day…

I'd normally say buy a lottery ticket with such foresight, but it's becoming entirely predictable on this forum

 

[init6]

Thanks for putting my mind to rest. If I adjust the pressure to be correct now, won't they be over pressure come spring? I presume we don't get over pressure warnings?

You should be maintaining your tyre pressures on a regular basis. If they are over pressure you can always take some air out.

There's a big chunk in the manual about maintaining tyres:

Model 3 Owner's Manual | Tesla

Learn about tire specifications, tire pressures and seasonal tires.

www.tesla.com

 

[hgmichna]

Thanks for putting my mind to rest. If I adjust the pressure to be correct now, won't they be over pressure come spring? I presume we don't get over pressure warnings?

That is correct.

I usually correct the tyre pressure when the outside air temperature changes by several degrees.

Because pumping up is much more awkward than letting some air out, I usually overcompensate a bit as winter approaches, in expectation of temperatures falling further. I also take the temperature forecast into account.

 

[Adopado]

If I adjust the pressure to be correct now, won't they be over pressure come spring?

I genuinely thought this was a joke when I first read it!

 

[WllXM]

That time of the year again

Winter with a Tesla

It’s the time of year when this forum starts to get new winter related posts. Thankfully there is already a wealth of information in the forum. We’ll take it as read that few people read the manual and the advice it contains for cold weather. Let’s start with probably the most common query as...

teslamotorsclub.com

 

[init6]

I genuinely thought this was a joke when I first read it!

It's a very real problem

 

[MrBadger]

Teslafi can only get the readings when the car is moving as that is the only time the TPS is active, therefore the resting pressure will always be the pressure when last driven.
The next drive the pressure will probably be lower at the start as the tyres have cooled.

As does the app and on screen display. It was a change this year that started to display stale readings from previous drive rather than leaving them as blank. I think the car and/or app shows the last reading time so you can tell that they are stale. When changing seasonal wheels, it takes about 2/3 minutes/mile of driving for new sensors to be detected so I am guessing (backed up by my TeslaFi jump in reading at similar distance) its similar amount of time for the new pressures to be picked up. This is certainly a good thing to have even though some pressures will be stale as long as you can tell they are stale readings and it doesn't cause confusion which I think might be happening here.

 

[Dangerous Fish]

How on earth did we cope before TPMS?