Hi guys,

I’m not sure if this has been asked or not, can’t find anything on here relating to it, but I have been trying to figure out when the on board computer thinks my tyres are a different psi to what the pumps say.

I have used my own inflator that I purchased from Amazon, I’ve tried the local ones at Tesco and Asda. All of which have been set to 33psi, however after around 5-10 mins the computer seems to think the tyres are 35psi.

Anyone have any ideas as to why this is? Or how to fix it?

Cheers

 

9 hours ago, simonjwakefield28 said:

 however after around 5-10 mins the computer seems to think the tyres are 35psi.

 

Now, is that after 5/10 minutes when driving? If so, the pressure will naturally increase as the tire temp rises...

1 hour ago, StephenFord said:

Now, is that after 5/10 minutes when driving? If so, the pressure will naturally increase as the tire temp rises...

Yes, after a bit of driving. Does this mean I should inflate to roughly 31psi before hand, for it to achieve 33psi after driving? Or leave as is? 33 is recommended for my tyres.

1 minute ago, simonjwakefield28 said:

Yes, after a bit of driving. Does this mean I should inflate to roughly 31psi before hand, for it to achieve 33psi after driving? Or leave as is? 33 is recommended for my tyres.

Leave as is. I believe the recommend pressures are for cold tyres. someone correct me if I am wrong. 

YOG excellent label but that advice will only work in the USA, here in the UK we only have Tyres !!!!

I suppose he could give it a try but will it work with British air ? 🤣

5 minutes ago, unofix said:

I suppose he could give it a try but will it work with British air ? 🤣

It will now that Brexit has been actioned, that EU air was rubbish!

Mine were showing 39 front and 37 rear yesterday in the bit of sunshine 🤣

 

1 hour ago, unofix said:

YOG excellent label but that advice will only work in the USA, here in the UK we only have Tyres !!!!

I suppose he could give it a try but will it work with British air ? 🤣

You'll need to have a word with Ford, who's Owners Manual 2020 Mk4 Owner's Manual CG3784en 08-2020 uses Tires and Brakes!! 😄

silly site duplicated

 

these sensors are a safety aid they aren't guaranteed to be 100% accurate - that said probably better than any pump or gauge you have that cost less than 60 quid...

the idea being, if its say 8 PSI off track let the driver know.  Note the old decent garage pumps have a certain way to operate that will get u 2 PSI difference... on the decent ones, once you think you are there, depress the trigger to the first notch and let out a smidgen and it will give the tyre pressure, not the air line pressure.

Also TPMS sensors always move with temps and atmospheric pressure changes... leave it set on Bar as you have a greater tolerance to have all 4 set the same... PSI jumps about and offends the eyes

 

Agreed. Although they're only supposed to be a guide I have a professional hand held gauge and the tpms pressures are always within 0.5psi of the gauge

 

16 minutes ago, Comares2001 said:

Agreed. Although they're only supposed to be a guide I have a professional hand held gauge and the tpms pressures are always within 0.5psi of the gauge

 

My TPMS system is very accurate too, though I'd expect it to be, cost me £20 (4 x sensors & display) all the way from China!

I have a fairly cheap Halfords digital guage and was surprised to find both that and the sensors read exactly the same.

As others have said, the pressure increases as the temp increases.  

That’s great guys, maybe I’ll invest in a gauge and check the TPMS vs the gauge and see where I am after that.

Other than that, as long as i get them to the recommended level cold, everything should be okay 👍🏻

Stephen that looks like way too much technollogy you have in your car, before you know it you will Stop/Start and LED headlights 😄