Tyre pressure is different on the size of Tyre and the weight of the
Van.
My question is how accurate or
The machine that blows the tyres up.
And how often do they get calibration done?.
I'm asking because I've had different reading from different machines.
As I always check mine before I go on a trip and ALWAYS cold
No one on here will know how often the calibration gets done, the only people who might know are the forecourt attendants. But that would be a stretch.
------------- XVI yes?
As well is two words!
How does a sage know everything about everything? or does he? or does he just think he does?
Remember, if you buy something you bought it, not brought it.
Are you referring to tyre inflators on garage forecourts?
If so they have a +/- tolerance when installed of around 5%. Add in the way a lot of people abuse them and it doesn't take long to make the 5% more like 10 or 20%.
I carry my own tyre pressure gauge and always use that to check the pressures. Not claiming my gauge is accurate but it's consistent.
Not sure too many people expect the gauge on a forecourt pump to be accurate, and from rather unscientific anecdotal checking/comparisons by various people/organisations over the years that expectation seems to be justified!
I'd use one to inflate my tyres, BUT I'd use my own gauge to verify pressure, as wouldn't trust an unknown gauge!
They will be accurate enough at manufacture, but have heard that Trading Standards who have responsibility for checking continuing accuracy don't have the resources to do so, so they are largely unchecked and could be wildly inaccurate!
Just had my car serviced at a main dealership, when I checked tyre pressures (verifying they were inflated to heavily loaded pressures for towing the van) I found they were not at the recommended pressure, but over inflated for normal running and underinflated for heavy loads! It went into garage with them at loaded pressure, so someone has meddled with the inflation to an incorrect figure, now that could be a incompetent fitter, or an inaccurate gauge on their airline, but either way, not to be trusted!
Often overlooked is that recommended tyre pressures are COLD figures as you mention, even a short journey to garage can raise the pressure by the heating of the tyres due to flexing and heat from brakes. I recently fitted Tyrepal pressure/temperature sensor system to my caravan wheels, and it was 'enlightening' (well aware of the technical facts, but not the timing before fitting) at how quickly the tyre pressure (and temperature) rose once on the road, within only a mile the pressure was well up and close to the maximum that it reached on a much longer journey! Set your pressures to recommended figures, even with an accurate gauge, after driving any distance to a forecourt and you'll likely be technically underinflated!
AND as some do, the practice of deflating hot tyres to get back down to the recommended figure is just WRONG! Allowances are made for normal pressure increase in hot tyres, even the MAX allowable pressure marked on the sidewall is a COLD figure, not a pressure never to be exceeded under running conditions!
By the comments I'm going to invest in a good gauge.
It's not good that you cannot trust the forecourt ones, considering you have to pay for them.
I'm old enough to remember when it was free.
Sadly you get nothing free now
I use a Michelin tyre pressure gauge and when air is required I use a 12v pump ( from Amazon ). The pump allows you to preset the pressure required and stops pumping once the pressure is reached. I have checked the accuracy between the guage and the 12v pump and they both give similar results.
Whether any particular gauge is accurate is perhaps not so important although I am sure there are regulations stipulating that garage forecourt air pumps should be accurate to within certain parameters. Best to buy a gauge that use use all the time to get consistency. I use a Halfords digital monitor.
last year i fitted a tyrepal system to my van.. for what its worth after traveling for twenty minutes or so the tyre pressure reads about 5 psi more than at the start of the journey..
what is an unknown is just how recommended tyre pressures are arrived at in the first place.. i dont think its as critical as some people think it is..
Quote: Originally posted by trog100 on 16/9/2023
.. i dont think its as critical as some people think it is..
trog
When I first picked my van up from the dealers, it handled like a total pig, despite the nose weight subsequently turning out to be very heavy (heavy nose weight generally improves handling!), even at moderate speeds on reasonable roads the ATC was kicking in frequently, I wondered what the hell I'd bought if it was so bad at 40 and 50mph! Turned out the tyres were under inflated, only a few PSI, but more significant percentages - one by 15%, the other by 20%! After inflating to correct pressure and lightening the nose weight it's been a dream to tow in all conditions over thousands of miles, even at accidental over 70mph.
So maybe tyre pressure is not so critical on some vans, no personal experience to pass comment on, but certainly on others it can be the difference between a 'dangerous' liability and a dream tow!
I have never relied on garage tyre inflators to be accurate, I always check them with my own. As has already been said, even if my own gauge is not 100% accurate, at least it is consistent. I very rarely use garage inflators anyway, I have my own and check my tyres before I leave home so that my tyres are cold.
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets
Topic: Tyre pressure
via mobile 15/9/2023 at 4:16am
