Tyre pressure warning after pumping up [SOLVED]

[StuartT]

My pressures were getting a bit low, so I went to a garage and pumped them up to 29psi on the machine. But the sensor in the car is now showing them lower than when I started (21psi)! Is this an error people have seen? They certainly look correctly inflated by eye.
Thanks

 

[Tuareg]

Most TPMS systems need recalibrating if tyres are reinflated to any higher pressure.

 

[webhiker]

Try testing the pressure at another garage

 

[StuartT]

Most TPMS systems need recalibrating if tyres are reinflated to any higher pressure.

Really? So every time I pump the tyres it needs recalibrating?!

How do I do that?

 

[Bricktop X PWR]

Really? So every time I pump the tyres it needs recalibrating?!

How do I do that?

Fill to the pressure you require on a Trusted machine.

Drive away.

Takes a few minutes for the sensors to transmit a change of reading to your dash.

Do you have a trustworthy gauge at home to double check the reading?

 

[StuartT]

Fill to the pressure you require on a Trusted machine.

Drive away.

Takes a few minutes for the sensors to transmit a change of reading to your dash.

Do you have a trustworthy gauge at home to double check the reading?

Hmm... it's been an hour now.

Ok, I'll try and find a gauge. Thanks

 

[Tuareg]

Hmm... it's been an hour now.

Ok, I'll try and find a gauge. Thanks

mg4 tpms reset - Google Search

 

[StuartT]

I’m such an idiot!!

I needed to pump to 2.9 bar, not 29psi

?‍?‍?‍

Sorry for wasting your time

 

[Bricktop X PWR]

I’m such an idiot!!

I needed to pump to 2.9 bar, not 29psi

?‍?‍?‍

Sorry for wasting your time

Appreciate your honesty.

We've all been there!

 

[Bogrole]

Glad you fixed it, and I read all the way through the post too!

 

[Ian Key]

Could have been worse. A number of years ago the driver in front of me at the air pump was taking a long time to blow up the front tyre on their mini. I went to see if I could help and they were trying to put 26 bar instead of 26 psi into the tyre.

[ Moderator: sexist comment removed. ]

 

[scal]

Isn't 2.9 bar a bit much? IIRC the recommended pressure is 2.55 bar (37 psi) all round, 2.8 bar (41 psi) at the rear when loaded.

I know you don't have the best weather in the UK but I hope you don't have to drive on winter tyres in August. (as winter tyres usually need a bit more pressure)

 

[Ian Key]

I run mine at 38 psi (2.6 bar) all round. The tyres appear to be wearing evenly and it stops the low pressure warning.

 

[Rolfe]

Me too.

 

[tsedge]

I set mine to 2.7 bar on my inflator which gives me 2.6 bar once they've settled.

First time since winter that I had to add pressure was last week. (warning came on, dropped just below 2.4 bar on one of the tyres).

 

[NLMGSAN]

Front tyres dropped from 2.5 yesterday to 2.3 this early morning. But temp also dropped from 27 degrees to 11 when I drove off. Within 5 kms the pressure was again 2.5 and by the time I arrived (at 13 degrees C) they reached both 2.6 bar. If that no longer happens, I will add some air.

 

[StuartT]

Isn't 2.9 bar a bit much? IIRC the recommended pressure is 2.55 bar (37 psi) all round, 2.8 bar (41 psi) at the rear when loaded.

I know you don't have the best weather in the UK but I hope you don't have to drive on winter tyres in August. (as winter tyres usually need a bit more pressure)

ok. Thanks for that. I'm not sure where I got 2.9 from. I'll deflate them a bit.

 

[Rolfe]

I got my first tyre pressure warning of the "winter" about 30 miles into my 450 mile road trip today. THAT'S how horrible the weather was in Scotland and northern England. It cleared after my first charging stop.

 

[siteguru]

Just as a reminder (to all) ... tyre pressures should be set when cold. If the ambient temperature is, say, 10°C and you set 37 psi, if the ambient rises to, say, 20°C (without the car having moved) then the pressure within the tyres will have increased. (Rule of thumb says it would increase by between 1 and 2 psi for every 10°C increase).

Further, driving the car will warm up the tyres, which will further increase the pressure.

 

[Ian Key]

Further to @siteguru's reminder that the same applies to the ambient temperature. If you've set the tyre pressures on a warm day in the summer when the cooler weather arrives they will need pumping up.