[ashis89]

I know the pressure gauge might be faulty at most of the places. I don't have much extreme usage of the tyres so my focus has been overall ride and handling of the car. Hence I found my own solution to the problem - consistency for each fill.

I try to fill air/nitrogen in my tyres from 1-2 fixed places unless I am travelling out of city for extended periods where I will need a refill within the trip. I have chosen this place after getting the tyre pressure checked at multiple places and finding the one which gave me the best experience during the ride. My assumption is that even if this particular gauge is at fault, the error will remain for each fill that I do at the same place.

Similarly, whenever I fill air, I make sure to do it at a place with a digital pressure gauge. My assumption - if there's any error in the gauge, it will be consistent across all the tyres. I have avoided the tyre walas with analog pressure gauge. Apart from faulty reading of the gauge, there could be more sources of error - zero error of the meter or parallax error by the user.

I fill up with nitrogen and find a 1-2 PSi drop over 4-5 weeks which is good enough for me. However due to lack availability, I have topped up with air as well on a couple of occasions.

Let me know if I am going wrong anywhere.

[Jeroen]

Originally Posted by sukiwa

How do we calibrate or what's your method for re-calibration?

The obvious answer is to find somebody who does calibrations. But that is neither practical or very cost efficient I dare say.

In my home country it is a little easier. MOT stations who perform annual checks on cars have calibrated gauges. They need re-calibration every year. The get checked regularly so these guys ensure that their equipment is working properly.

That is how I found out, my own gauge was way off.

From a practical point of view you can consider a couple of things. Gauges/manometer wear easily. So anything that has been used for a couple of years is likely to be off. A good gauge cost money. If you can buy, or use a (relatively) new gauge of some known good brand.

Compare the reading by using different gauges from different places. See if you notice any differences in reading. If you use five different gauges and three give a (near) identical reading, it is very likely that the correct pressure is somewhere near what those three are telling you.

Look at your tires before you inflate them. On most tires 0.4 bar too low tends to be visible, once you get a bit of an eye for it.

It’s good practice to feel the temperature of your tires after motorway driving. They should be warm to the touch, but not too warm. Tires heating up are a sign of under inflating (or sticky brakes).

But if you just checked your air pressure and then drive 100 km on the motorways, feel the tires and they are very warm, the gauge you were using is likely to be off by a good margin.

Good luck

Jeroen

[a4anurag]

Before the start of the drive


After completing the drive


City speeds (max): 45 kmph
Highway speeds (max): 100 kmph
No. of persons in the car: Only me.
Ambient temperature: 29 degrees

Of the 77 kms, 45 kms was on the ORR maintaining speeds between 95-100 kmph and the rest 32 kms were inside the city.

Found an increase of 2psi in the front tyres and 1psi in the rear. The rear right tyre has a puncture. Will be getting that checked in the evening since the puncture kit is at home.

[Chetan_Rao]

How accurate are portable inflators that work off the 12V socket? Any reliable ones?

[IndigoXLGrandDi]

Originally Posted by a4anurag

Before the start of the drive
Attachment 1834494

After completing the drive
Attachment 1834495
Ambient temperature: 29 degrees

Can you please clarify the reason behind increase in the tyre pressure of spare tyre? I understand it's only 1psi. But still.
Is that the temperature increment of 11 Deg caused the increase in tyre pressure?

[a4anurag]

Originally Posted by IndigoXLGrandDi

Can you please clarify the reason behind increase in the tyre pressure of spare tyre?

It was 34psi so I asked the MRF guys to top it up to 36psi.

[arun_josie]

Originally Posted by Chetan_Rao

How accurate are portable inflators that work off the 12V socket? Any reliable ones?

I am using Coido 3326 for the last 5 years. No issues so far. My regular tire pressure checks are done at fuel stations/tyre shops though.

[kishgator]

Originally Posted by aspire

You will damage your bearing, if you drive with tyres inflated above the recommended pressure.

Right, i had to replace one rear wheel bearing recently, however the dealer was recommending replacement since last 3 services for a high amount, got it myself from auto parts and installed at fraction of cost

[Jeroen]

Originally Posted by IndigoXLGrandDi

Can you please clarify the reason behind increase in the tyre pressure of spare tyre? I understand it's only 1psi. But still.
Is that the temperature increment of 11 Deg caused the increase in tyre pressure?

Originally Posted by a4anurag

It was 34psi so I asked the MRF guys to top it up to 36psi.

I always keep my spare tyre about 0,5 bar (7-8 psi) above the normal tyre pressure. Spare tyres just doesn't get checked for correct pressure as often as the regular tyres.

Over time, just about all tyres deflate, so adding a bit of extra pressure on the spare so it has a bit of buffer.

Jeroen

[IndigoXLGrandDi]

Originally Posted by a4anurag

It was 34psi so I asked the MRF guys to top it up to 36psi.

Originally Posted by Jeroen

I always keep my spare tyre about 0,5 bar (7-8 psi) above the normal tyre pressure. Spare tyres just doesn't get checked for correct pressure as often as the regular tyres.

Over time, just about all tyres deflate, so adding a bit of extra pressure on the spare so it has a bit of buffer.

Jeroen

Sorry if I was not clear enough.
I wanted to know the reason behind the increase in Spare wheel tyre pressure even though it did not run on the ground.

The temperature of Spare Wheel was 18 Deg and 29 Deg before and after the drive, respectively.
Hence I asked whether the increase of 11 Deg caused the tyre pressure of spare wheel to increase by 1psi.

[goandude]

Recently did a highway drive from hyderabad to bangalore. These are the readings from my TPMS sensors which came as OE with my i20 sportz.
At start of drive 33F, 31R, ambient temp 17 degrees
After 131 kms 35/32 temp 19
After 200 kms 36/33 temp 24
After 350 kms 37/35 temp 32
Speeds consistently between 80 to 95 kmph

I realise that tyre pressure stabilises after 30 /40 kms of driving to about 1/2 psi above cold, thereafter it depends on ambient air temperature. Rising approx 1 psi for 5 degrees rise in temperature

[AutoNoob]

Originally Posted by IndigoXLGrandDi

Can you please clarify the reason behind increase in the tyre pressure of spare tyre? I understand it's only 1psi. But still.
Is that the temperature increment of 11 Deg caused the increase in tyre pressure?

Yes. And Gay-Lussac's law provides the mathematical relationship for the same. Though it's for Ideal gas, where as air is mixure, it still is true.

Originally Posted by Jeroen

I always keep my spare tyre about 0,5 bar (7-8 psi) above the normal tyre pressure. Spare tyres just doesn't get checked for correct pressure as often as the regular tyres.

Over time, just about all tyres deflate, so adding a bit of extra pressure on the spare so it has a bit of buffer.

Jeroen

Same here. I keep spare tire about 5 psi above rated. One reason is the decrease in pressure over time. Second, it's easier to release air from tire incase it's installed, rather than filling-up to right pressure on side of road/ highway with portable pump.