Out to shops today and shortly after setting off got message ‘front right tyre loss of pressure’. Stopped and checked the pressure, 33psi (normally 36). No obvious nail/damage. So continued (carefully) to shops and back home when I jacked the car up and had a good look all round the tyre. Again, nothing to see. So I inflated back to 36 and left it.  Just checked it again after 3 hours and no change. 
 

It’s possible that since I last checked it the tyre has lost pressure as they often do over time. Re the TPMS, I’ve had one or two false alarms in my Golf over my 11 years of ownership. I think that it works via the ABS sensor and can be activated if a tyre picks up some mud which alters its rotation characteristics but there was no evidence of that. 
 

Has anyone had a similar experience?

Temperature can affect it 

14 minutes ago, Doofy said:

Temperature can affect it 

Yes I get that but why just one tyre? Or did you mean the sensor on that axle?

How long ago were the pressures checked and set when cold, or similar temp til todays?

 

Good that it indicated a change since last checked pressure and the TPMS reset.

If reset now and all well good if it warns again if there is a change at some point.

 

It is just the circumference it knows, and a over heating bearing or sticky brakes can heat up a wheel / tyre, or sitting with the sun hitting a tyre.

The pressure was lower though so a win. 

What pressure were the other three tyres, or didn't you check them?  If the front right tyre has a slow puncture, then eventually this may set off the low pressure warning.  I've had a number of false alarms over the years with my Fabia and Kamiq when going over an uneven bit of road at speed, e.g. an expansion joint on a bridge.

54 minutes ago, marineboy said:

Yes I get that but why just one tyre? Or did you mean the sensor on that axle?

There is an ABS sensor on every wheel. If only one tyre was (not) in the sunlight I'd expect it to be at a different pressure to the others.

1 hour ago, Seasider said:

What pressure were the other three tyres, or didn't you check them?  If the front right tyre has a slow puncture, then eventually this may set off the low pressure warning.  I've had a number of false alarms over the years with my Fabia and Kamiq when going over an uneven bit of road at speed, e.g. an expansion joint on a bridge.

Yes I did check the other tyres. All at 36. And I’ve just checked the suspect one and it’s still 36. I’m thinking perhaps that it does have a VERY slight leak and over the last few weeks since I checked all the tyres its pressure has reduced to the point where it triggered the sensor. 

2 hours ago, marineboy said:

Yes I did check the other tyres. All at 36. And I’ve just checked the suspect one and it’s still 36. I’m thinking perhaps that it does have a VERY slight leak and over the last few weeks since I checked all the tyres its pressure has reduced to the point where it triggered the sensor. 

 

You normally need 6-8psi pressure loss to have the system give a warning. That is how it has been on all of my cars with indirect TPMS.

Not a hard and fast rule though.

Easy enough with an accurate tyre pressure gauge.   Set pressures, reset the TPMS then after all well let one down by 4 psi. 

There can be maybe a little pressure loss and some tyre tread wear, it is only the circumference and rotations of the wheel being measured.

 

A more sensitive system and a warning is a good thing as running 5 psi low because regular checks done is not 'Simply Clever'. 

On 21/02/2024 at 19:30, Routemaster1461 said:

 

You normally need 6-8psi pressure loss to have the system give a warning. That is how it has been on all of my cars with indirect TPMS.

My winters appear to be foreign body magnets, regular slow punctures from screws, etc 😒 - my TPMS reliably flags at approx. 0.5 bar / 7PSI.

Edited 22 February, 20242 yr by Warrior193
add emoticon

Interesting comments re the amount of pressure drop needed to trigger the warning, ie 6 to 8 psi. The fact that my offending tyre was only 3 below the others (and possibly a bit less than that), and there has been no further reduction in pressure over the last few days, leads me to think that the warning was triggered either by a bit of debris on the tyre or sensor or a software glitch. 

Or just because the pressure once home was only 3 psi lower than when set.  But maybe if you are a tyre pressure guage when the warning activated and checked pressures it might not have been only 3 psi.   This same subject comes up regularly.   Good actually people get random warnings because in the owners manuals it advises to do test checks. 

Daughter's Kamiq threw up a warning today on the way to our house.  Basic ABS based system so didn't say which wheel it was bothered by.

 

Pressures should be 2.5bar (36psi) and all 4 tyres were 2.2 (32psi).   I was quite surprised that all 4 were exactly the same.

What matters is what they were each at when the TPMS was last set.  Were they all at the same pressure then?

 

Who set the pressures and the TPMS last?

I checked them day car was delivered (Nov 23) and they were 2.5bar.

 

It's been in for warrranty work a couple of times recently so it's possible they adjusted them to the wrong pressure (our Karoq's pressures are 2.1bar).  If not then it's remarkable they were all 2.2 bar (and my digital pressure gauge displays in 20ths of a bar, less than 1 psi, so it's a fairly fine reading).

18 hours ago, Rory said:

I checked them day car was delivered (Nov 23) and they were 2.5bar.

 

It's been in for warrranty work a couple of times recently so it's possible they adjusted them to the wrong pressure (our Karoq's pressures are 2.1bar).  If not then it's remarkable they were all 2.2 bar (and my digital pressure gauge displays in 20ths of a bar, less than 1 psi, so it's a fairly fine reading).

That is plenty of time for them to lose 0.3 bar pressure and in my experience unless there is a problem with a tyre or valve or wheel, a set of  tyres tend to lose pressure pretty much uniformly.  On my Kamiq, for example, when I do a check (about once a month) each tyre is down to 2.4 bar.

I've never had a car where the tyres lost pressure on a regular basis like that.  The pressures on our Karoq don't budge.

The day delivered November 2023 might have been a different ambient temperature to today 29th July 2024 when check tyre pressure cold. 

 

@Rory Do you never check yours on the coldest of days or the hottest of days to see what they show?

Or ever adjust tyres to suit the weather or load carried?

I think normal pressures are based on 3 people and a bit of luggage and I’d never have the car loaded beyond that.

 

Must admit I don’t have any kind of routine for checking tyres beyond a visual check, yet I’m scrupulous with oil and washer fluid.

Daughter had to replace one of Kamiq's tyres today, after a puncture yesterday.

 

She came here afterwards and the tyre was at 2.7bar.    All the others at 2.2 again.  (Label in fuel flap sys 2.5bar (which is 36psi).   Car was serviced a week ago so I can only assume the garage set them at 2.2 again.    I'd have a word with the garage and they'll say the right things but do absolutely nothing.

 

I also find it stange that Kamiq's spec is 2.5bar, yet our Karoq is 2.1 bar - both on 18" wheels, although Kamiq's tyres are 45 profile and Karoq's are 50.

 

 

3 hours ago, Rory said:

I also find it strange that Kamiq's spec is 2.5bar, yet our Karoq is 2.1 bar - both on 18" wheels, although Kamiq's tyres are 45 profile and Karoq's are 50.

 

The standard load indexes of these two tyre sizes are different, so the 45 aspect ratio tyre needs more air pressure to support the same weight as the 50 aspect ratio tyre.

 

The 205/60R16 tyre size on the Kamiq has the same load index as the 215/50R18 tyre size on the front wheel drive Karoq...as shown in the chart below.

 

Standard Load index of tyres

205/60R16 92(630kg)

215/45R18 89(580kg)

215/50R18 92(630kg)

 

Edited 3 November, 20241 yr by Carlston

14 minutes ago, Carlston said:

The 16" tyres on the Kamiq are 205/60R16 which has the same load index as the 215/50R18 tyre size...as shown in the chart below.

 

Standard Load index of tyres

205/60R16 92(630kg)

215/45R18 89(580kg)

215/50R18 92(630kg)

This might actually mean something if you showed how the load index calculations are done.

Tyre Load Index Chart

Use the table below to find the load and speed capacity from the markings on your tyres: 

https://www.goodyear.eu/en_gb/consumer/learn/how-to-read-your-tire-sidewall-markings.html

4 hours ago, Carlston said:

Use the table below to find the load and speed capacity from the markings on your tyres

Not what I asked. I asked "how are the calculations done?" rather than "can you post a lookup table?"

Probably smart people with a degree, note books, slide rules and computers came up with them.

Now just the computer and AI can do it.

 

They can maybe also bother actually checking the tyre pressures and adjusting them which is more than many drivers do.