Which is correct?

Blaster 84 · 07-07-2013, 08:22 PM

This week I had our RV worked on and the technician brought all the tires up to proper pressure. I didn't see him do it and he didn't say what that pressure was. The next morning I decided to recheck them. My pencil type gauge indicated 50 psi, my digital gauge indicated 56 psi. What's the best way to determine which is correct?

B47 · 07-07-2013, 08:31 PM

Quote:

Originally Posted by Blaster 84

This week I had our RV worked on and the technician brought all the tires up to proper pressure. I didn't see him do it and he didn't say what that pressure was. The next morning I decided to recheck them. My pencil type gauge indicated 50 psi, my digital gauge indicated 56 psi. What's the best way to determine which is correct?

AFAIK there is no "best way", but I suggest you buy a quality air pressure gauge and only use that gauge to check the pressure.

IMO All tire pressures should be within 2-4 pounds of each other if there are no obvious defects, such as a leaking valve stem or flat tire and always check all the tires at the same time, preferably when they are "cold".

Over a period of time, you should learn if your gauge is reading the correct pressure or not.

Blaster 84 · 07-07-2013, 08:42 PM

I thought of that and I checked all the tires, they were consistently 6 lbs difference. It was first thing in the morning when I did it.

OldCoot · 07-07-2013, 08:54 PM

Quote:

Originally Posted by Blaster 84

I thought of that and I checked all the tires, they were consistently 6 lbs difference. It was first thing in the morning when I did it.

Either borrow another gauge or buy another one that is a top of the line and check them. It is like B said, just get some confidence in whatever one you like and use it.

**ependydad** · 07-07-2013, 10:25 PM

What's the joke?

A man with 2 watches never knows what time it is.

bakken · 07-07-2013, 10:32 PM

Check which gauge was made in China, and use the other one!

But seriously, spend a few bucks and buy a good gauge, worth every penny.

polkatronron · 07-08-2013, 05:05 PM

Go to a truck supply house and spend a good buck and get a good one. This Chinese crap is not accurate. I did and I have had his gusge now for ten years and it is dead on.

OldCoot · 07-08-2013, 05:10 PM

Quote:

Originally Posted by polkatronron

Go to a truck supply house and spend a good buck and get a good one. This Chinese crap is not accurate. I did and I have had his gusge now for ten years and it is dead on.

And how do you know it is 'dead on'?

roanmountaincampers · 07-08-2013, 05:18 PM

What is a good gauge? Where do I buy one?

roanmountaincampers · 07-08-2013, 05:21 PM

Quote:

Originally Posted by OldCoot

And how do you know it is 'dead on'?

Good point. How will I ever know how accurate a gauge is. Maybe I should just stick with my Wal Mart special. My Dad taught me when buying a thermometer to check them all in the store and buy one that agreed with the majority on display. How can I do that with a tire gauge??

OldCoot · 07-08-2013, 05:25 PM

This one might fill the bill.
Longacre Racing - Online Catalog: Electronic Wheel Scales, Gauges, Pyrometers, Chassis Setup and More!

JLeising · 07-08-2013, 05:32 PM

I bought three gauges - one for home, one for the car, and one for the RV. Took immediately to the parking lot of the auto parts store and measured a tire on my car. Two agreed; one read about 4 lbs higher. I took that one back and exchanged it (twice) until I got a third that agreed with the first two. I then set my tire pressures to the level I wanted using these gauges.

Just got my MH back from 20k service. I told the service center (a Ford dealership) to set the tire pressures at my desired levels - which I believed the tires were already at. Ford lowered the pressure in all six tires by ~5 psi. Apparently Ford's gauge agreed with the one I returned - and not with the three I kept!

mikegp1 · 07-08-2013, 05:43 PM

I actually use my gauge setup from my dirt modified. I have a triple gauge setup. One is setup to go to 30 and the other to 120. I made them both up. Work like a charm.

Blaster 84 · 07-09-2013, 07:04 PM

I took my two gauges to three different tire shops and asked them which one is correct. The first shop said they have no way of knowing and if we compared with their technicians they would all be different. The second shop said they didn't trust digital gauges but also commented that some times the pencil type gauge would drag. The third shop noted that my pencil type gauge had a 120 lb. max reading and he felt the gauge would not be accurate at the lower readings. He tested both gauges and said the digital gauge is definitely was the most accurate.

I observed that during this testing the readings were getting closer to each other and sometimes read the same. I believe the pencil type gauge did become inaccurate do to lack of use. The more I used it the more accurate it became. In the future I'll rely on my digital gauge.

rockfordroo · 07-09-2013, 07:23 PM

I would be surprised if even a good quality gauge (one you could afford) would be better than about 3% accurate. (As you can see above, a 0.1% accurate gauge will cost you $3200!!) On a 100 psi gauge, 3% is 3 psi. If yours was 3 psi high and the tire shop was 3 psi low, you'd be 6 psi apart. Not surprising. Without finding some place that truly has a highly accurate gauge that's periodically calibrated against a standard, to which you can compare, the best you can do is buy a quality one and hope for the best. Mine's a Craftsman dial gauge that cost me about $15.

rockfordroo · 07-09-2013, 07:25 PM

BTW, my Craftsman dial gauge compares very well with the TPMS readout in my wife's Chevy Traverse. Within a psi or two.

B47 · 07-09-2013, 07:28 PM

Quote:

Originally Posted by Blaster 84

I took my two gauges to three different tire shops and asked them which one is correct. The first shop said they have no way of knowing and if we compared with their technicians they would all be different. The second shop said they didn't trust digital gauges but also commented that some times the pencil type gauge would drag. The third shop noted that my pencil type gauge had a 120 lb. max reading and he felt the gauge would not be accurate at the lower readings. He tested both gauges and said the digital gauge is definitely was the most accurate.

I observed that during this testing the readings were getting closer to each other and sometimes read the same. I believe the pencil type gauge did become inaccurate do to lack of use. The more I used it the more accurate it became. In the future I'll rely on my digital gauge.

I commend you for all the effort and energy you have put into trying to find the most accurate tire pressure gauge.

The only other input I have, other than what I posted earlier in this thread, comes from my experience as a FAA Airworthiness Inspector assigned to a major U.S. airline. That being that the FAA requires major airlines is have a procedure to ensure that any equipment used to determine the final airworthiness status of a component is periodically calibrated to determine it is performing its function correctly. Such equipment includes VOM, electrical measuring devices, torque wrenches etc. Also included are tire pressure gauges because airlines usually check tire pressures on overnight maintenance checks.

These gauges, as you might suspect, are not the usual ones you can buy at your local auto supply store - they are very rugged and I never saw any pencil type gauges used, only the analog type. I can't comment on the digital type because I never saw those being used.

Bottom line - go with the digital or analog gauge IMO.

B47 · 07-09-2013, 07:33 PM

One thing I failed to mention here is that any gauge that is dropped is required to be taken out of service and re calibrated before it can be used again.

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