I've been thinking about this for a while and I can't come to a solution I'm happy with.... Years ago a mate of mine who ran a very expensive (car) wheel and tyre business drove around the local servo's checking pressure gauges. No real surprise, he found all of them were wrong and almost none of them matched. So, if I ignore servo gauges, I have one each on both my air compressor tyre inflators plus one that came with the 4wd compressor, plus another that came with a deflator set I bought and one old dial one that I found in a 4wd I bought once. (for no reason I can explain, I trust that old dial gauge the most.) My problem is that I can't figure out a way to find out which of them, if any, is accurate. I know it's a bit OCD but I'd love to be able to say "this is the accurate gauge, ignore what the other ones say". Can any of you suggest a way to check the accuracy of a gauge? Alternatively, do you have a preferred brand of gauge that you are confident is accurate?
No idea how accurate it is but its good to use and Im guessing that digital would have to be more user friendly than a dial http://www.bunnings.com.au/ozito-digital-tyre-inflator-tif-dit_p6270641
Factors of safety and margins of error come up all the time in my industry (engineering) - and for the most part unless it's life threatening or going to cause some catastrophic injury its not really given that much attention. Most of the time the specifications on the gauge will tell you +/- how accurate it is meant to be and for the rare instances I've checked it's normally fallen within those boundaries. I'd be picking a good quality gauge, checking the margin of error and using that as a benchmark if you're really concerned. You can then use that to compare to other readings you have gotten from other bits of equipment. To your point it would probably be very OCD and overly pedantic to attempt to compare several gauges and try to ascertain which is the most accurate - you'll most likely get a range and you'll simply be doing it forever. Analogue gauges are usually always more accurate than digital ones due to the rounding normally exhibited in a digital display, but it depends on how skilled you are at reading the analogue one and how many DP's you really care about (ie +/- 0.1, 0.01, 0.001 etc). The only time I've ever noticed a difference on my tyres is if they're about 5PSI off the mark which theoretically speaking is a huge drop.. but you deflate your tyres for certain conditions (eg wet weather) so it's not like it's a problem exactly - you adjust your riding to suit. My tyre pressures give two recommendations for rider only and rider + passenger, I'm normally happy somewhere in the middle as I'm a big bloke and don't often take passengers. End Novel.
Thanks @joker, that generally fits with what I was thinking. You know what they say - a man with a watch knows the time, a man with two watches is always unsure
the reason it would have changed due to driving around to each one to check them would have been that the pressure changes due to temperature. That's like thinking a multimeter is wrong when checking circuitry on different days with the temperature being different giving different resistance. Odds are when your friend was driving around the gauges where all correct and within a certain tolerance. not to mention the very small amount of air that gets released each time you check it etc. The cheapest solution would be to check the pressure at home before riding with something like this perhaps http://www.ebay.com/itm/Hella-Diagn...ash=item3cfbd5112a:g:PBUAAOSwBahVd5m6&vxp=mtr There is much cheaper but the Hella name and the fact that its chrome will heal the ocd a little.
I was able to buy a tyre gauge from 4 wheel online, forgot the brand, but compared the reading with an industrial gauge used by air craft maintenance. It shows about 90% correct reading.
Interesting stats....was the 10% variance on the upside or downside??? Would be easy enough to compensate for the variance if you know.
Its more of upside, but very minimal difference. I just remember the brand its Viair. You can just search it over 4 wheel online for more info.
If you tune into Dave Moss, he will tell you that you will test your gauge regularly against a known pressure. I'd be better off paying for classes teaching advanced skills than I would throwing money to have my gauge tested. I treat my analog gauge with care, making sure it's not dropped. The measurements from my gauge are repeatable from day to do, within tolerances my skills are capable of. If I start roasting tires, I might worry about pressures a bit more.
