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Accurate air pressure


belfastguzzi

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Does anyone know if their air gauge is really accurate? What can it be measured against? Is the only way to guarantee an accurate measurement to spend a lot of money on a top qualty professional instrument?

 

Although they get slated in the press, I suspect that the old stick/pencil gauges that I have are as accurate as anything. The digital gauges that I have bought all read differently. These are mostly Halford branded. I recently bought Oxford's digital gauge as it claims to be highly accurate, but am disappointed to find that it under-reads by 2 lb/sq' compared to the other gauges I checked against. But is it the correct one?

 

The Halfords digital and the sticks are a closer match than the Oxford, which has been recommended in the press.

 

It doesn't matter so much with car/truck tyres, but for the motorbike it would be nice to know to a better accuracy than 2lbs.

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Guest aironepony
Does anyone know if their air gauge is really accurate? What can it be measured against? Is the only way to guarantee an accurate measurement to spend a lot of money on a top qualty professional instrument?

 

Although they get slated in the press,  I suspect that the old stick/pencil gauges that I have are as accurate as anything. The digital gauges that I have bought all read differently. These are mostly Halford branded. I recently bought Oxford's digital gauge as it claims to be highly accurate, but am disappointed to find that it under-reads by 2 lb/sq' compared to the other gauges I checked against. But is it the correct one?

 

The Halfords digital and the sticks are a closer match than the Oxford, which has been recommended in the press.

 

It doesn't matter so much with car/truck tyres, but for the motorbike it would be nice to know to a better accuracy than 2lbs.

53803[/snapback]

 

 

The British Standard Tyre Gauge (lbs/sq inch) is in a glass case at Greenwich and is used to calibrate all BS474756 gauges .................... :thumbsup:

 

The SI unit version is usually housed in a temperature and humidity controlled environment in the basement of the Louvre, Paris and is currently on loan to the Getty Museum............. :thumbsup:

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is currently on loan to the Getty Museum............. :thumbsup:

53805[/snapback]

well, if they loan it out... :bbblll:

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well, if they loan it out...  :bbblll:

53806[/snapback]

Gentlemen,bring your gages to a calibration house, anybody in manufacturing knows all your tools need to be calibrated. Done deal!

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My gauges are all over the place, regardless of price...

rossoct tells it right!

My biggest peeve is trying to find a gas station that has a hose that reaches my valve stem properly.

Many are angled wrong or have donuts on the hose to protect the air fitting.

Donuts are for my belly :food:

But I guess if I never used my bicycle pump, I'd get even less excercise. :2c:

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...for the motorbike it would be nice to know to a better accuracy than 2lbs....

I agree, but I think we worry too much about tyre pressures. Maybe I'm insensitive but in normal use, 2lb either side of correct isn't critical to me. I also find gauges vary a lot but, over time, learn which ones are closest to average & therefore probably correct(ish)....

Trouble I had with pencil gauges is stiction affecting reading. I once wrecked a new tyre in a few laps on track on a very hot day. It was about 4 or 5 lbs out as I recall...

 

....My biggest peeve is trying to find a gas station that has a hose that reaches my valve stem properly....

The things hardly ever fit: I carry an angled valve adaptor.

 

KB :sun:

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The pencil type gauges are wildly inaccurate, especially as they get dirty. Just spraying some light lube into one can make the reading change considerably. Digital gauges should not suffer this problem but they can be calibrated incorrectly, especially if they come from some unknown assembly plant in Bangladesh or whatever. I have one of the ones that the BMW dealer sells, and I have no reason to doubt that it's calibration is probably very close to the actual pressure being read. It's just a good tool. Priced like a SnapOn I suppose, but worth the investment.

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The pencil type gauges are wildly inaccurate, especially as they get dirty. Just spraying some light lube into one can make the reading change considerably.

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Well, yes, but you're not meant to spray lube on them. Thick grease would have a serious effect too, the other way.

 

The local garage here has a new (new to here anyway) type of air supply. You set the required pressure on a digital display on the pump and then it stops when the pressure is reached.

No more very inaccurate analogue gauge on the hose. But whether it is accurate, I don't know. Certainly, it is closer to the reading on my own gauge(s).

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Well, yes, but you're not meant to spray lube on them. Thick grease would have a serious effect too, the other way.

 

They get dirty, they read wrong. Ya spray'em. They read different. Probably still wrong. They're only generally indicative of the pressure. I don't trust them for accuracy.

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Perhaps we should be using gauges that are calibrated (and accurate) in Bar(s) rather than p.s.i.

 

well if you've just come out of the bar..... wrap your lips around the valve stem, depress the valve with your tongue.. If your face blows up like Dizzy Gillespie then there's probably enough pressure to get you home...

 

Not that I've ever tried this of course... I just know people..

 

Cheers.Tim

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wrap your lips around the valve stem, depress the valve with your tongue..

53883[/snapback]

 

That kind of sh** is illegal and there are some very specific penalties outlined in the USA Patriot act.

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That kind of sh** is illegal and there are some very specific penalties outlined in the USA Patriot act.

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marc_marshal.jpg

What Maryland commuters to D.C. get to look at....

My guess is that a graphics artist was requested to come up with a poster, and figured, why beat around a bush, and just get straight to the point. The Russians sure had some great artists!

Have you narc'd on your "unusual" neighbor lately?

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