Checking Tire Air Pressure At The Filling Station

[Isan Farang]

I had some doubt that the fuel station air gauge would not be accurate so I had a friend send over a gauge from the states.

When I went yesterday the air gauge was a digital type and you dial in what pressure you need. I was very surprised that when I double checked with my own gauge it was correct.

[KhunBENQ]

In the past I have done some comparisions between different air-pressure devices at the filling stations.

Differences were not bigger than 2 psi. Acceptable I would guess.

But as the devices at the filling stations are defect very often I gave them up.

I bought a cheap device (less than 100 Baht) and have a manual pump (less than 300 Baht).

The simple gauge is precise compared with the values from the filling stations.

Such type of a simple device, suprisingly the readings are accurate and reproducable

[transam]

Lucky boy, I never trust their gauges. Tesco do sell a few different types of tyre gauges as well as 12V air pumps, cheap..

[daveAustin]

Fuel station compressors are not to be trusted and should be used in conjunction with above plunger-type tester. As a motorist, one of those should be a part of your in-car kit. Daily (or at the least before longer journey) checks should be de rigueur.

[chris2004]

I was thinking of getting one of those compressor tyre inflators you use via the 12v socket. Are they worth it for 1,000 baht or so. Saves me on the foot pump.

[transam]

I was thinking of getting one of those compressor tyre inflators you use via the 12v socket. Are they worth it for 1,000 baht or so. Saves me on the foot pump.

Tesco sells a few types at various prices. The gauges on them are useless. Think I paid about 1000bht for a pump and stand alone gauge. The rubber hose on the pump is crap and rots at the pump end, so when it leaks cut it off, remove an inch, buy a weee hose clip and refit...

[bdenner]

A filling station's air pressure gauge may be inaccurate but (if working) will be consistent. Just check the pressure in a tyre you know is OK and pump the suspect tyre to the same pressure. Will get you by in the short term.

[LivinLOS]

https://www.facebook.com/video.php?v=276106732513040&video_source=pages_finch_main_video

I got one of these.. digital gauge, accurate readings (checked with a pressure slide and digital stand alones) and decent package. Also good quality screw on valve end, not those pressure only types.

Wish they made one small enough to go under my tail seat space on the fireblade..

[whatawonderfulday]

The biggest problem is not the calibration/testing of the fuel station gauges rather the incompetence of the personnel. in my previous business I insisted that tyre pressure on my company vehicles were checked by competent personnel weekly. In 99.9% of the case where the operatives allowed filling stations to check their tyres they were over inflated by up to 30 %. No wonder so many accidents occur as over inflation does not allow tyres to "work" as they were designed..

Not of course that bothers most people here as they have no idea of what there tyre pressures should be. They have no comprehension as to the safety aspects anyway. This is not just a Thai problem as even so called HSEQ Farang executives, who purport to push individual safety to their own personnel, I have found to be totally ignorant of their own vehicles tyre pressures so what chance the locals have in driving safely is anyone's guess.

[Pinot]

I have a calendar email reminder to check the tire pressure on my motorbikes (2) and car monthly. I bought a step-on tire pump for 300 baht. I have found that that I can lose 1/3 of the tire pressure in a month. I commonly see it go from 30 psi to 20. None of my friends ever do this. I'm the only one. I think most people are driving around on significantly under-inflated tires.

The tire pump gauge and the tire gauge I have read close together. The tire gauge was 100 baht and the pump was 300 baht. I ride on properly inflated tires but I'm one of the few.

[SantiSuk]

I have a calendar email reminder to check the tire pressure on my motorbikes (2) and car monthly. I bought a step-on tire pump for 300 baht. I have found that that I can lose 1/3 of the tire pressure in a month. I commonly see it go from 30 psi to 20. None of my friends ever do this. I'm the only one. I think most people are driving around on significantly under-inflated tires.

The tire pump gauge and the tire gauge I have read close together. The tire gauge was 100 baht and the pump was 300 baht. I ride on properly inflated tires but I'm one of the few.

[Brock]

Most tyre pressure gauges, are manufactured to a certain standard ( well they are supposed to be) where the accuracy is + or - 3% of full scale reading. so for a gauge with a full scale reading of 100 PSI, the reading can be + or -3PSI. so for a required pressure of 40 PSI in your tyre, the actual pressure could be really any where between 37 and 43 PSI. Comparing a gauge bought else whereto the service station gauge, is of no real benefit as now the accuracy of the comparative gauge comes into question, so the error now could be + or - 6 psi. how ever both gauges could be within their tolerances. Unless the comparative gauge has been tested on a master calibrated gauge, usually of a tollerance of .5% or better, you have no way of knowing which is more correct.

This is an argument I have had with many people over the last 6 years, when I was working in a calibration lab doing gauges for the RAAF (Royal Aust Air Force)

[ToddinChonburi]

yes it also changes as your tires warm up. Need to check monthly before you start to drive in the morning would be best.

[Shadychris]

Most tyre pressure gauges, are manufactured to a certain standard ( well they are supposed to be) where the accuracy is + or - 3% of full scale reading. so for a gauge with a full scale reading of 100 PSI, the reading can be + or -3PSI. so for a required pressure of 40 PSI in your tyre, the actual pressure could be really any where between 37 and 43 PSI. Comparing a gauge bought else whereto the service station gauge, is of no real benefit as now the accuracy of the comparative gauge comes into question, so the error now could be + or - 6 psi. how ever both gauges could be within their tolerances. Unless the comparative gauge has been tested on a master calibrated gauge, usually of a tollerance of .5% or better, you have no way of knowing which is more correct.

This is an argument I have had with many people over the last 6 years, when I was working in a calibration lab doing gauges for the RAAF (Royal Aust Air Force)

Best answer here so far! To be 100% sure of accuracy 'any' instrument needs regular calibrating against a 'standard' master device. It's also the fact that tyre pressure is affected by operating temperature roughly 3% per 8 degree C. This means that if you check the pressure cold at home after the car has stood for 15 mins or so in the shade and then take it out and give it some good hard cornering and braking action in the midday sun and then immediately take a reading it will be a few more psi than it was the first time. If you pull into to a garage and check then as Brock says, you could have both the stations garage tolerance plus your gauge tolerance plus the heat increase to consider - so there may be a difference of up to 10 psi!

I tend to always check tyres cold using my own gauge and pump. I start at manufactures recommendations and then adjust to my driving style and typical car load, I usually end up with a setup that is slightly lower than recommended on the front and slightly higher on the back. Keep an eye on your tread wear too, wearing faster on the outside edges - add more pressure (check tracking too), wearing faster in the middle - bring the pressure down a tad.

Remember manufacturer tyre pressures are recommended figures only, it's not critical to match them exactly - just be careful to ensure you have the same pressures on both sides of vehicle. Imbalance laterally across the car can cause control under heavy braking to become ... shall we say interesting ;-)

[bazza40]

It's a problem with the spoked wheels on motorbikes or scooters because they lose pressure quite rapidly. The moulded carbon fibre wheels seem to be much better. I have to check my scooter's wheels ( cold ) once a week. I check the car once a month.

I also have a tyre gauge for both car and scooter, the automated compressors at most garages can actually deflate a tyre if they malfunction.

[tomloughney]

I had the motorcycle tire tube replaced, got home on a hard tire, checked it and it was over 100 psi. No need for a gauge if you run your tires that hard, the gauge is hard, very hard, extra very hard and rock....easy to check......

[Isan Farang]

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Most tyre pressure gauges, are manufactured to a certain standard ( well they are supposed to be) where the accuracy is + or - 3% of full scale reading. so for a gauge with a full scale reading of 100 PSI, the reading can be + or -3PSI. so for a required pressure of 40 PSI in your tyre, the actual pressure could be really any where between 37 and 43 PSI. Comparing a gauge bought else whereto the service station gauge, is of no real benefit as now the accuracy of the comparative gauge comes into question, so the error now could be + or - 6 psi. how ever both gauges could be within their tolerances. Unless the comparative gauge has been tested on a master calibrated gauge, usually of a tollerance of .5% or better, you have no way of knowing which is more correct.

This is an argument I have had with many people over the last 6 years, when I was working in a calibration lab doing gauges for the RAAF (Royal Aust Air Force)

Best answer here so far! To be 100% sure of accuracy 'any' instrument needs regular calibrating against a 'standard' master device. It's also the fact that tyre pressure is affected by operating temperature roughly 3% per 8 degree C. This means that if you check the pressure cold at home after the car has stood for 15 mins or so in the shade and then take it out and give it some good hard cornering and braking action in the midday sun and then immediately take a reading it will be a few more psi than it was the first time. If you pull into to a garage and check then as Brock says, you could have both the stations garage tolerance plus your gauge tolerance plus the heat increase to consider - so there may be a difference of up to 10 psi!

I tend to always check tyres cold using my own gauge and pump. I start at manufactures recommendations and then adjust to my driving style and typical car load, I usually end up with a setup that is slightly lower than recommended on the front and slightly higher on the back. Keep an eye on your tread wear too, wearing faster on the outside edges - add more pressure (check tracking too), wearing faster in the middle - bring the pressure down a tad.

Remember manufacturer tyre pressures are recommended figures only, it's not critical to match them exactly - just be careful to ensure you have the same pressures on both sides of vehicle. Imbalance laterally across the car can cause control under heavy braking to become ... shall we say interesting ;-)

Somchi at PTT informed me they failed the ISO 9000 due to the fact there gauge is not certified with a master calibrated gauge, they also had no sticker attached when the next calibration was due.

[Isan Farang]

I had the motorcycle tire tube replaced, got home on a hard tire, checked it and it was over 100 psi. No need for a gauge if you run your tires that hard, the gauge is hard, very hard, extra very hard and rock....easy to check......

[Nuddy]

The gauges are not really the problem I have found.

Knowing the correct pressure required seems to be an issue.

And then getting that attended to also presents a problem here in .

[jesimps]

I would suggest that if you borrow the English language, you use the correct spelling ie tyre not tire (to become tired). I like Americans but their abuse of the English language is a pet hate of mine. While we're at it why do they use hard vowels like in Iraq, Iran and amen but use soft ones when hard ones are called for? Rant over, carry on.

[Pinot]

I'm a tire (note spelling) pressure guy. I love this thread.

Here's the problem with measuring your tire pressure at a service station...when you get there, the tires are hot.

How do you pros from Dover account for this?

Or is do it home, when the tires are cool, the only way? A cool tire at 30, can go to 40+ when it's hot.

[Pinot]

The gauges are not really the problem I have found.

Knowing the correct pressure required seems to be an issue.

And then getting that attended to also presents a problem here in .

The factory spec on my three vehicles, car and two different brand motorbikes, are all 29/33. I live a charmed life.

[mha noi]

In non mechanical non aircraft terms. the psi rateing on the tyre is its max load..the apporitate rating for your daily needs should be on a stiker or plague inside your glove box or near the door pillar(where the door contacts the body,left right front or back ,upon make car) i have tailgates pop open due to potholes but no tyres.touchwood. i dnt think most of us are running around in F1 cars or airplanes on thai roads, so from my experience id run an average sedan 28 to 32psi. Myself i had a small suzuki 4wd and because it weighed so little i ran 22 to 26 psi to stop so much of the bounces because the car wasnt heavy and shocks can be helped. also ran 18 psi in a low profile tyre on a muscle car pickup. So a psi variation i dnt think will kill you. Stand looking at your tyre looking straight on to its tread and if its highest point is in the middle you have way to much pressure. If its bulgeing at the out at the bottom you dont half enough psi. Hope this helps non mechanicaly minded people. KISS (keep.It.Simply.Stupid)

[jacko45k]

In the past I have done some comparisions between different air-pressure devices at the filling stations.

Differences were not bigger than 2 psi. Acceptable I would guess.

But as the devices at the filling stations are defect very often I gave them up.

I bought a cheap device (less than 100 Baht) and have a manual pump (less than 300 Baht).

The simple gauge is precise compared with the values from the filling stations.

Such type of a simple device, suprisingly the readings are accurate and reproducable

Beware those types. I dropped one and never noticed a slight ding in it. All the readings were several psi low and I had been riding around on overly hard tyres. I got suspicious as I use a stand pump and was breaking sweat more.

[bdenner]

I'm a tire (note spelling) pressure guy. I love this thread.

For a Tyre (note spelling) guy are you so naive as not to know the USA is not the centre (note spelling) of the Earth.

[2fishin2]

I would suggest that if you borrow the English language, you use the correct spelling ie tyre not tire (to become tired). I like Americans but their abuse of the English language is a pet hate of mine. While we're at it why do they use hard vowels like in Iraq, Iran and amen but use soft ones when hard ones are called for? Rant over, carry on.

Idiot!

[2fishin2]

I would suggest that if you borrow the English language, you use the correct spelling ie tyre not tire (to become tired). I like Americans but their abuse of the English language is a pet hate of mine. While we're at it why do they use hard vowels like in Iraq, Iran and amen but use soft ones when hard ones are called for? Rant over, carry on.

Go back to school, here let me help you:

http://en.m.wikipedia.org/wiki/Tire

[Pinot]

I'm a tire (note spelling) pressure guy. I love this thread.

For a Tyre (note spelling) guy are you so naive as not to know the USA is not the centre (note spelling) of the Earth.

At 350 million people, we may be the center of the English earth.

[transam]

This is OUR motoring forum.........Can we back off the spelling thing chaps..........

[sirineou]

Life must be very boring in Isaan lately

what's next, checking the water pressure at public restrooms in shopping malls

and how do they spell shopping malls in southern Kyrgyzstan?