How do YOU check your tyre pressure is accurate?

[Collin]

We're told that tyre pressures are so crucial, yet I am constantly frustrated at efforts to get an accurate pressure reading.
Garage pressure gauges, as everyone knows, are notoriously unreliable.
So I bought a good quality digital gauge and it read 3 psi higher than my old gauge. Then I bought a Michelin compressor and that showed a 2 psi difference.
So when I had a new tyre fitted, I reasoned that a specialist company would surely have very precise gauges and I asked the fitter specifically to put in 32 psi on his gauge so that I could check his reading against mine. Sure enough, my gauge showed a 2psi difference - it read 34. Cracked it, I thought. Just remember that my gauge reads 2 psi higher than is correct and add another couple of pounds.
I've worked on this principle for some time, but am now totally disillusioned after being told my by another tyre fitter that none of their gauges are necessarily very accurate.
So it's back to square one for me, and my question is, does anyone have a failsafe system to establish that their tyre pressures are accurate?

 

[Parksy]

Tyre pressures can vary with temperature changes anyway so I wouldn't have thought that 2lb/p.s.i. over would make a lot of difference.
What started out as 32lb/psi might read 33 or 34 at the end of a journey so if the guage was 100% accurate the tyre pressures would have to be checked when cold. I use the digital guage on my tyre inflator and I work to the principle that as long as the tyre pressure readings are the same for each tyre when cold and are within the limits in the handbook I have done all that could reasonably be expected of me.
Regular inspection of the tyres would soon reveal if the reading was way out.

 

[TheTravellingRooster]

Hi to you all out there. The first thing that I do is avoid the garage tyre pressure equiptment,on two counts. Firstly,you have to drive to them to use them,that gives a false reading straight away,defeding upon ambient temperature of the atmosphere and the time of year you can be forcing damp/wet air into the tyre,NOT A GOOD IDEA. The unreliable nature of them caused by abuse, even if the air is bone dry in the Summer you have higher ambient temperatures that then give doubley false readings,and the pressure could rise between 4lb psi & 7lb psi just on a 1mile trip to the fuel station pressure guage. Our Twin Axle Caravan is also subjected to all of the same problems,but the implications don't bare thinking about.
I use a Cigar Lighter Powered Compressor and have 1 digital gauge that has shown (by substitution/comparison with my other 3 gauges to be the most consistently stable).I have fitted an after-market Cigar Type Socket into the caravan the powers my battery top-up Solar Panel just in front of the twin axle position so as to be able to inflate the caravan tyres as & when needed. The 12v curly type extension leads proved to be a waste of time,current draw kept blowing fuses on the extension lead in-line fuse facility.
The one thing that I now have is consistancey,and as Paksey says 2lb psi up or down is of little consequence in the greater scheme of things. That said, I will often put a broad band of White Chalk right across all Eight Tyres after loading and ready to go,and after a hundred yards or so look at the loss of chalk pattern to indicate the 'footprint' of each tyre. Then adjust accordingly,up or down.

 

[mcghee]

what you need is a big u-guage!

 

[Taff]

I was told that if the garage does not charge for air to put into your tyres, they do not have to ensure the gauge is accurate, However some garages charge for the air you use and they must ensure the gauge is accurate.

 

[TD42]

I have the old type Michelin analog??? type pressure gauge,the one that pushes out a metal column. being totally mechanical there is nothing to go wrong. I always use this to check my tyres whatever the method used to inflate them

 

[Philspadders]

pcl in sheffield make forecourt air supplies. As they leave the factory these units are fully calibrated at 20degc.

however , forecourt temps are up an down , the air temp changes etc. Unless you measure your tyre pressure off the car, at 20degs c with incoming air to the compressor at 20 degc ( and of course as air is compressed it coosl anyway)your readings will be all over the place,

Best bet is take 3 gauges and at the same time take 3 readings and use the average reading as the correct pressure.

 

[forestgump]

dont be to harsh on your self the fact off heat and what you hav`e in the vanat the time will be diffrent .I use a digge one and as long as its with in 3 or 4 lbs i am ok with that.

 

[Collin]

Thanks guys, I can see now that tyre pressures are not an exact science and I can see why I get different readings. I like Phil's approach best as I already double check with my own gauge and the built in compressor gauge. I guess I can easily make a third check with my analogue "push out barrel type" which I thought was unreliable (due to possible grit, wear, etc), but I'll dig it out!

 

[weejock]

If your old barrel type is old it may not be too reliable if any of the seals have perished a bit.

Keep doing what your doing and remember if the tyre wears in the middle it is over inflated and at the sides it is under inflated.

The idea of the chalk mark is a good one though

 

[joeby]

a car website were testing tyre pressure gauges and one of the most accurate was the Draper 69924 analogue gauge which can be bought from www.thedrapershop.co.uk or various other web sites , i keep mine in the garage and check mine once a week before leaving , but i also carry a digatal gauge in the car ,which i check against the draper one

 

[ProfJohnL]

It is very difficult for the normal consumer to know how accurate any of these gauges may be.
TD4 if a gauge is offered for use by the public whether it is payed for or not the gauge must be reasonable accurate. Its the same principal as the scales that supermarkets locate near loose produce.
A number of respondents are using digital gauges, and I am pleased to read that they check them against other gauges to ascertain their relative accuracy. I have a Halfords pump with digital pressure gauge and pre set cut off, and unless it set up and used exactly as the instructions the gauge can be highly inconsistent.
I always double check with pencil type gauge after inflating. For reference I have access to a calibrated industrial gauge. I have always been surprised at how consistent the pencil gauge has been always producing a reading of approx 0.1 Kpa lower than the calibrated gauge.

 

[joeby]

the pencil guages are very accurate , and were very highly rated ,and very easy to stow away ,nobody should be with out one , i shouldnt think the average person has a fail safe system

 

[chrisbee1]

I am fortunate in that where I work all our gauges are calibrated every 6 months.My pencil type gauge is also checked at the same time and seems to keep it's accuracy. Additionally, I have nitrogen filled tyres which are claimed to stop the pressure leaking through the tyre material. It seems to work okay, the pressures have remained constant for at least the last two years.

 

[Collin]

Thanks Joeby, I like the look of the Draper so I have just ordered one for a tenner. (You'd better be right!! lol). It will be check number three, behind the digi and the Michelin compressor!!

 

[ChrisUK]

Good question this one. It concerns me too. I went to my local tyre dealer that I always use and asked if I could check my guage against one of theirs. Bit surprised, and so was he, that theirs varied by a few pounds. I bought an expensive digital one from Halfords which generally seems OK, but I went out to use it yesterday and it wouldn't work. Too cold for the electronics (I keep it in the car).

 

[xtrailman]

I have found tyre pressures can increase without turning a wheel, just by being in the sun, or the ambient temperature increasing.
I use a 15 year old pencil gauge, and always add a couple of psi for luck.

 

[joeby]

http://www.autoexpress.co.uk/front_website/gallery.php?id=369901 this gauge was not the winner but was commended

 

[Past_it]

I have 2 old style pop out ones and a digital........ they all give different readings.
Oh dear, problems problems.