measuring tire pressure

[Jon A.]

ok, beginner question.  the auris manual (those that have a compressor instead of a tire) state that the compressor should be only used for emergencies. 

but do any of you measure tire pressure regularly with that compressor? after a search in the internet i came to the conclusion that majority of the tire pressure gauges will be inaccurate, so maybe the compressor could be used as a go to  means for both checking the pressure and the tire pump?

[eygo]

i'd go and buy a digital tyre pressure gauge

dial pressure gauges are never that accurate even when new

they are for indication purposes to buy a calibrated gauge

would cost more than the pump.

[TonyHSD]

I use similar to that one for pumping up the tyres and than get the exact measurements with digital One and things are going well. It is important to do so when car been stationary for more than an hour and never after even a short run, once the tyres are moving they heat up and pressures goes higher, i mean a lot higher. 

 

[Countrylad]

Most of these pumps are badly flawed for anything more than the occasional top-ups, not least because the screw-on fitting that goes onto the valve is such an iffy arrangement. (From the moment it goes fffffffffffft to the moment it seals, you could have lost 3 psi!) Bring back the old snap-on fittings, at least they were quick and decisive.

What annoys me more, though, is that when the tyre pressure warning on the dashboard lights up, it doesn't tell you which tyre is soft. (And it might be by only 1 psi, so a visual inspection isn't necessarily going to make the difference either.)

And then, when you get the pump out, have you ever noticed that the soft tyre is always the last one you try? Which means that the other three are now probably over-pressure. Oh joy.

 

[eygo]

i'm sure i've heard that you have to loose 10% of tyre pressure before the tpms light comes on.

[Byzii]

The problem with any, and I mean any gauge you can buy (even the absurdly expensive ones which cost more than 300 pounds) is that they're inherently inaccurate, and they require professional calibration very often.

Sadly there's no simple and affordable way for the average person to make sure their tires are always at correct pressure. Best one can do is to buy a somewhat reputable brand gauge and then frequently go to a place which gets its equipment calibrated. When that place checks the pressure, immediately check it with your gauge and note down the difference, then again check with calibrated equipment to see how much air is being let out when installing the gauge.

Again, the problem is that this has to get done on a monthly basis since the common gauges one can buy can change their readings based on whether the pigeon landed on a left or right side of the branch of the tree overlooking your car.

[eygo]

at work i have to get the pressure gauges calibrated, the calibration isnt what you'd think.

a machine is used to apply pressure to a gauge then the needle is removed

and replaced to read the correct pressure as this is the only way to change the way the

needle reads, inside there is a copper pressure pipe that expands when pressurized 

this in turn move the needle.