Tyre drops pressure then stops....

Tips, tricks, questions and answers to tech questions
User avatar
Count Steer
Posts: 11830
Joined: Mon Jul 19, 2021 4:59 pm
Has thanked: 6381 times
Been thanked: 4761 times

Re: Tyre drops pressure then stops....

Post by Count Steer »

Every time the ambient temperature drops the shopping trolley car reports low pressure in the rear offside tyre (down 1psi :roll: ). Stuck the air hose on the first few times, reset the system (what a faff). Stopped bothering - just corner with a bit more gusto and warm the tyres up. :)
Doubt is not a pleasant condition.
But certainty is an absurd one
.
Voltaire
Mr. Dazzle
Posts: 13955
Joined: Mon Mar 16, 2020 7:57 pm
Location: Milton Keynes
Has thanked: 2552 times
Been thanked: 6257 times

Re: Tyre drops pressure then stops....

Post by Mr. Dazzle »

Yeah temperature is deffo a thing, but;

The TMPS logs temperature anyway. I don't know if it's smart enough to equate a drop in temperature with a drop in pressure, but I'd have to assume it is. Why else bother measuring it? Detect overheating tyres I guess....

Only one wheel drops and it drops sorta 30% on top of what you'd expect from being cold. The other three also drop, but less, like you'd expect. Indeed I check the pressure when I'm driving* usually rather than when static, which is what the manual says to do so you correctly set the pressure for the climate/use.

Weirdness abounds!

*voice activation FTW :D "Guten tag frauline car, what are the tyre pressures?"
User avatar
KungFooBob
Posts: 14218
Joined: Sat Mar 14, 2020 1:04 pm
Location: The content of this post is not AI generated.
Has thanked: 539 times
Been thanked: 7535 times

Re: Tyre drops pressure then stops....

Post by KungFooBob »

Have you upset any witches, voodoo priests or old gypsy women recently?

I suspect your car has been hexed.
iansoady
Posts: 418
Joined: Thu Mar 19, 2020 10:12 am
Has thanked: 59 times
Been thanked: 169 times

Re: Tyre drops pressure then stops....

Post by iansoady »

1 kPa is approx 15 psi.
Mr. Dazzle
Posts: 13955
Joined: Mon Mar 16, 2020 7:57 pm
Location: Milton Keynes
Has thanked: 2552 times
Been thanked: 6257 times

Re: Tyre drops pressure then stops....

Post by Mr. Dazzle »

iansoady wrote: Wed Oct 02, 2024 10:17 am 1 kPa is approx 15 psi.
100kPa :)

I pump my tyres up based on bar, 'cause my pump reads that (and psi) but the dashboard reads out in kPa and that's what's written on the inside of the fuel filler flap - dead easy though, 'cause it's just 100:1. Thus 290kPa is just 2.9bar.

I ain't done psi for ages :lol:
Mr. Dazzle
Posts: 13955
Joined: Mon Mar 16, 2020 7:57 pm
Location: Milton Keynes
Has thanked: 2552 times
Been thanked: 6257 times

Re: Tyre drops pressure then stops....

Post by Mr. Dazzle »

KungFooBob wrote: Wed Oct 02, 2024 8:57 am Have you upset any witches, voodoo priests or old gypsy women recently?

I suspect your car has been hexed.
Would fire help?
User avatar
KungFooBob
Posts: 14218
Joined: Sat Mar 14, 2020 1:04 pm
Location: The content of this post is not AI generated.
Has thanked: 539 times
Been thanked: 7535 times

Re: Tyre drops pressure then stops....

Post by KungFooBob »

The flames of cleansing will certainly help in this situation.
iansoady
Posts: 418
Joined: Thu Mar 19, 2020 10:12 am
Has thanked: 59 times
Been thanked: 169 times

Re: Tyre drops pressure then stops....

Post by iansoady »

Mr. Dazzle wrote: Wed Oct 02, 2024 10:27 am
iansoady wrote: Wed Oct 02, 2024 10:17 am 1 kPa is approx 15 psi.
100kPa :)

I pump my tyres up based on bar, 'cause my pump reads that (and psi) but the dashboard reads out in kPa and that's what's written on the inside of the fuel filler flap - dead easy though, 'cause it's just 100:1. Thus 290kPa is just 2.9bar.

I ain't done psi for ages :lol:
Yes of course.
Supermofo
Posts: 5002
Joined: Mon Mar 16, 2020 3:39 pm
Has thanked: 4362 times
Been thanked: 2852 times

Re: Tyre drops pressure then stops....

Post by Supermofo »

I had a tyre that was losing pressure from the rim but the car is 8 years old so assume that's corrosion which won't apply to yours. But could the bead not have seated correctly regardless?
User avatar
dern
Posts: 2141
Joined: Wed Aug 18, 2021 8:51 am
Has thanked: 1016 times
Been thanked: 1776 times

Re: Tyre drops pressure then stops....

Post by dern »

Wossname wrote: Tue Oct 01, 2024 6:29 pm Pump it up to 290 or whatever, take it off, spray it all over with soapy water and look for the bubbles. Unlikely to be a faulty wheel but that would be a warranty situation. Most likely a tiny puncture.
This will work. Attempting to divine the cause using the power of the internet won't.
Mr. Dazzle
Posts: 13955
Joined: Mon Mar 16, 2020 7:57 pm
Location: Milton Keynes
Has thanked: 2552 times
Been thanked: 6257 times

Re: Tyre drops pressure then stops....

Post by Mr. Dazzle »

Well either I've fixed it, or it's fixed itself :lol:

I had a look yesterday, checked with the manual gauge and it was 200kPa, like the dashboard said. On a whim I manually let it down to about 100kPa and then pumped it all the way back up to 290.

It stayed at 290 for my drive to work this morning just fine.

I can only assume the tyre was very slightly unseated, or perhaps a tiny bit of something was stuck in the valve. Letting it down and re-inflating might have done the trick, touch wood.
Le_Fromage_Grande
Posts: 11234
Joined: Mon Mar 16, 2020 6:40 pm
Location: The road of many manky motorcycles
Has thanked: 607 times
Been thanked: 4124 times

Re: Tyre drops pressure then stops....

Post by Le_Fromage_Grande »

We don't need to know about you touching your wood
User avatar
KungFooBob
Posts: 14218
Joined: Sat Mar 14, 2020 1:04 pm
Location: The content of this post is not AI generated.
Has thanked: 539 times
Been thanked: 7535 times

Re: Tyre drops pressure then stops....

Post by KungFooBob »

Le_Fromage_Grande wrote: Thu Oct 03, 2024 9:40 pm We don't need to know about you touching your wood
Not without pictures.
Mr. Dazzle
Posts: 13955
Joined: Mon Mar 16, 2020 7:57 pm
Location: Milton Keynes
Has thanked: 2552 times
Been thanked: 6257 times

Re: Tyre drops pressure then stops....

Post by Mr. Dazzle »

Well I'm gonna continue touching my wood, 'cause my tyres still seem fine.