Tyre Gauges - How Accurate is Yours?

[Steffo1]

 I have just checked the camper tyres for a 3 day away break & it jogged my memory about when Broncos11, one of his mates (alright, his mate) & myself were on Fraser last month. We had about 1/2 a dozen gauges, both hand held & compressor air line types, between us & when tested, only 2 came within 2 PSI of each other with another, the one I used of course, Bloody Murphy, even being about 12 PSI different 
The 2 that "agreed" were the pencil shaped, graduated slide type but  there's no reason to believe they're correct either.
Has anyone ever calibrated a gauge & if so, how?
Steffo

[Bird]

you can send them away to get calibrated.. but why bother.

If you use 1 gauge, and stick with it, know how it reads, you will always be fine...

[knoath]

As Lost points out, at least if you are measuring all your tyres, you can inflate or deflate them at the same rate…

[Steffo1]

Fair enough but my point is, if a gauge is out by -8 PSI then when a tyre pressure recommendation is, say, 35 PSI then you're actually going to have only 27 PSI in it!

[Jeepers Creepers]

We had one calibrated years ago when we were drag racing, but it was in 1/4lb increments and very critical that it be correct.

The one I use in the Jeep is within 2 lb. of the fixed to wall ding dong type of gauge at the servo, so near enough for me.

[GraemeL]

Over what period did you test them?

early morning will be different readings than late in the arvo, they will also very when driving.

The TPMS unit will trigger a low pressure alarm early in the morning but will be up to 2 PSI different in the arvo.

[Mik01]

I don't worry about how accurate mine is - its only for inflating my tyres enough to get to a servo and 'properly' inflate them.
I am a bit anal about tyre pressures, and will always make a beeline for a servo with a decent gauge, particularly where I am doing a long trip home, to make absolutely sure all are where I want them.

but I have tested mine at a servo - same method as the tyre deflators - and mine is out about 2/3 psi

[Bird]

I don't worry about how accurate mine is - its only for inflating my tyres enough to get to a servo and 'properly' inflate them.
I am a bit anal about tyre pressures, and will always make a beeline for a servo with a decent gauge, particularly where I am doing a long trip home, to make absolutely sure all are where I want them.

how do you know theirs is accurate?

[Mik01]

how do you know theirs is accurate?

What is accurate then?
I'd trust a commercial grade compressor with electronic gauge than my cheap repco air compressor. But yes, could not be accurate, but then nothing is...?

[Pirate_Pete]

I have been doing a lot of hi way miles on my Cooper ATs. The car plate recommends 35 psi. I have been running them at 40 psi for a lower Rowling resistance & they are wearing nice & flat across the tread. I got then balanced & rotated at about 10000ks & told the tyre place what I have been running then at so they checked then & must have topped them up.

The car drove like a dog hopping & skipping about all over the place, even my daughter who is learning to drive noticed the diffrence in the ride.

I checked them with my gauge & let about 3 psi out of each tire.

So do I go by my gauge or theirs?

[Black Diamond]

I have been doing a lot of hi way miles on my Cooper ATs. The car plate recommends 35 psi. I have been running them at 40 psi for a lower Rowling resistance & they are wearing nice & flat across the tread. I got then balanced & rotated at about 10000ks & told the tyre place what I have been running then at so they checked then & must have topped them up.

The car drove like a dog hopping & skipping about all over the place, even my daughter who is learning to drive noticed the diffrence in the ride.

I checked them with my gauge & let about 3 psi out of each tire.

So do I go by my gauge or theirs?

Yours. Whatever pressure it reads whether it's right or not doesn't matter, if it works for you and it sounds like it did then Stick with that.

[Grayzo]

Head into your local CATERPILLAR dealership and pick up a CAT tyre guage.p/n 1P-0545. Been using one for about 16 years never let me down yet. Will set ya back $35.61 inc GST 

[prodigyrf]

Mine is accurate and all the rest are out 

[Bird]

What is accurate then?
I'd trust a commercial grade compressor with electronic gauge than my cheap repco air compressor. But yes, could not be accurate, but then nothing is...?

not even car speedos are accurate... Anything mass produced to a *spec* of something like +/- XXX is never going to be accurate.

The only accurate one I've ever used was one a mate used for road racing, he worked at Qantas as engineer and got it calibrated through/at work...

[Mik01]

not even car speedos are accurate... Anything mass produced to a *spec* of something like +/- XXX is never going to be accurate.

The only accurate one I've ever used was one a mate used for road racing, he worked at Qantas as engineer and got it calibrated through/at work...

So you understand the futility of your comment? If nothing is accurate, then tyre pressures are all wrong all of the time, and it doesn't matter what is used.
As I said, I'd trust one of those commercial jobs over my cheap compressor made in a sweatshop.
So one is likely more accurate than the other. Possible valid answer to the OP question I suppose.

[fishfinder]

who invented the pressure gauge and was he accurate at the beginning ? so all our gauges night be wrong

[edz]

Ok then seems as though gauges are inaccurate, forget PSI amounts ... just need to carry a ruler , lay it alongside each tyre , let air out till you get a longer contact point from the tyre.. repeat till all tyres match then go test / adjust as needed up or down by letting air out / adding air  .. if it works let down to that measurement each time .. 

[KingBilly]

As I said, I'd trust one of those commercial jobs over my cheap compressor made in a sweatshop.

I have seen servo gauges take some abuse with drivers just chucking them down on the driveway when they are finished so not sure how much faith I would put in one of them.  Plus most servos wouldn't care about their quality or accuracy anymore, just as long as there is a gauge on the end of the hose.

The sweatshop statement is a little broad.  Just because you pay a premium price, doesn't mean it was manufactured to higher standard.  Maybe you are just paying a premium for a known brand/make 

KB

[Steffo1]

From a tyre company. Check the under/over inflation comments.

[Jeepers Creepers]

I have seen servo gauges take some abuse with drivers just chucking them down on the driveway when they are finished so not sure how much faith I would put in one of them.  Plus most servos wouldn't care about their quality or accuracy anymore, just as long as there is a gauge on the end of the hose.

The sweatshop statement is a little broad.  Just because you pay a premium price, doesn't mean it was manufactured to higher standard.  Maybe you are just paying a premium for a known brand/make 

KB

The best servo ones that don't cop much abuse, are the wall mounted ding dong gauges, so all the dikheads get to stuff up is the airline itself.

As for the ones with the gauge at the inflation point, that's a whole new ball game, after they get dropped, kicked and run over each day.

[knoath]

Ok then seems as though gauges are inaccurate, forget PSI amounts ... just need to carry a ruler , lay it alongside each tyre , let air out till you get a longer contact point from the tyre.. repeat till all tyres match then go test / adjust as needed up or down by letting air out / adding air  .. if it works let down to that measurement each time .. 

Who's to say your ruler is accurately calibrated edz???

[Mik01]

I have seen servo gauges take some abuse with drivers just chucking them down on the driveway when they are finished so not sure how much faith I would put in one of them.  Plus most servos wouldn't care about their quality or accuracy anymore, just as long as there is a gauge on the end of the hose.

The sweatshop statement is a little broad.  Just because you pay a premium price, doesn't mean it was manufactured to higher standard.  Maybe you are just paying a premium for a known brand/make 

KB

I try to only use the electronic jobs - don't trust the manual gauge ones for the reasons you mention.
my statement isn't broad - I said I would trust the electric commercial jobbie than the other cheapie made for home job. 

would you seriously argue that my $99 repco job (which just died by the way, after less than a year and only being used 3 times) is likely to be as accurate as the electronic commercial air compressors at servos?

anyway, how long is a piece of string? I'm going to open a new thread titled - 'clocks - how accurate is yours?' 

[Bird]

So you understand the futility of your comment? If nothing is accurate, then tyre pressures are all wrong all of the time, and it doesn't matter what is used.

That may come as a shock to you that they are probably wrong most of the time, but hey thats life.
Nope, I know what I said, thus why I said it...

The only 2 things you can do are
1 - buy one and get it calibrated 1ce a yr cause bouncing around will more than likely change the calibration - also the more its used.
or as we all do
2-  buy one and work out the readings and if you wanna go down 20psi, then you go down 20psi on the reading...

Chances are if you bought 10 gauges of different makes/models they would all read different - a few maybe 100% correct they may not. Its just how it is...

When they mass produce things like this, they don't say 100% of the product has to be 100% correct - or the price would skyrocket... they say (example) + or - 3psi on the reading, and the cheaper the item, probably the larger that number is.

[KingBilly]

would you seriously argue that my $99 repco job (which just died by the way, after less than a year and only being used 3 times) is likely to be as accurate as the electronic commercial air compressors at servos?

Don't get so excited 

Now that you have elaborated and we now know you are talking about the electronic servo tyre gauges, the whole argument changes.  I was under the impression you were comparing like with like and comparing your Repco gauge with the older style gauge on the end of a hose at the servo.  If, and only if, the servo electronic gauges are calibrated regularly, then I would agree with you.

But there is no regulations saying they must be accurate or regularly calibrated according to the servo manger I just spoke to whilst topping up.

KB

[Bird]

Now that you have elaborated and we now know you are talking about the electronic servo tyre gauges

the digital one (where you preset the pressure that you want ) at the local el-cheapo servo reads different to my ARB and Michelin and the Mobil servo next doors digital gauges!