Is there any way to test if a tire gauge reads correctly?

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Is there any way to test if a tire gauge reads correctly?

November 21, 2020, 07:41:27 am

I have two analog gauges. One sold by Bookstone back when. And a "truck" gauge that has a flexible line that is great for checking the pressure.

Both read the same at low pressure. I carry 24 pounds in the Jeep tires.
I keep the LD front tires at 56. At that pressure, the gauges read 5 pounds different.
I have little expectation that either is correct. But I have gone along with the reading for years.
Is there a way to know the pressure shown is correct?

PS
I don't check pressure every day. I usually walk around with an IR gun at a rest stop and check for high temps.
I can't recall having to add air ever.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #1 – November 21, 2020, 09:02:42 am

If you really want to know, buy a ANSI certified gauge like this one:
ElitePro™ Tire Pressure Gauge - 100 PSI | JACO

Even then, certified gauges can vary by a psi or two and still be within spec.

If you know someone who is into motorsports (autocross or track driving), they could probably help you compare your gauges to theirs. Similarly, a performance focused shop would be able to help.

Rich

Re: Is there any way to test if a tire gauge reads correctly?

Reply #2 – November 21, 2020, 09:18:09 am

I purchased the above Tire Pressure 6 months ago on the recommendation of a LD Owner. It is easy to use, and if you read the specs below provided by the manufacturer you would probably have confidence that the readings are correct. If you go to the site of the recommended Gauge as posted above this was their information.

"2A) WHAT IS THE ACCURACY OF YOUR MECHANICAL GAUGES?
All of our mechanical gauges are designed, engineered, and performance tested at our ANSI and NIST approved industrial facility in Crystal Lake, IL. Our company's industrial testing facility is one of only a few facilities that are actually approved to certify gauges to the standards of ANSI, ASME, and NIST (others may say they are).

During production, each gauge is calibrated on professional calibration equipment to ±2% accuracy at the middle of the scale. We also check various other pressure ranges during calibration to ensure accuracy throughout the entire scale. We are approved by NIST to offer certifications to ANSI Standards, and most of our mechanical gauges are certified to ANSI B40.1 Standards. Since we take extra steps during calibration, our gauges often fall much more precise than our advertised specs.

Certified ANSI B40.1 Standards: each calibrated gauge is within 2% accuracy in the middle 25-75% range of the scale, and within 3% accuracy in the lower and upper quarters."

Cheers!

Tony R (aka codefour)

Re: Is there any way to test if a tire gauge reads correctly?

Reply #3 – November 21, 2020, 10:00:41 am

I have put a Jaco gauge in my Amazon cart. Not in stock right now.
Thanks for the info

Re: Is there any way to test if a tire gauge reads correctly?

Reply #4 – November 21, 2020, 10:05:23 am

The Jaco gauge shows as available on Amazon.

Amazon.com: JACO ElitePro Tire Pressure Gauge - 100 PSI: Industrial & Scientific

As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #5 – November 21, 2020, 10:46:00 am

I believe that most good tire stores can test your gauge for accuracy. As noted, if you are within a few percentage points, that meets spec but can make a difference of a few PSI at rig tire pressures.

My digital gauge is consistent. By that I mean if I do three checks of a tire, I will get the same number, within 0.5 psi, all three times. I have set my tire pressures based on handling. At 65 front and 70 rear, my Michelins allowed a fair amount of drift. When I went to all steel Goodyears, they recommended 70 and 75, and I had no drift, zero. When I wore out the Goodyears, I could not get recent manufacture Goodyears so I went back to Michelins. I began experimenting with pressures to find a pressure with less drift. For me, that is 73 psi front and 78 psi rear. If I am within 0.5 PSI of those numbers I am good.

So, for me, I am not concerned about matching a paper number. I want consistency side to side, and I want optimal handling and control. If my gauge is off by 2 psi, I really don't care. (FWIW, when I get rig service, tire pressures are checked, particularly if they rotate the fronts. Their reported pressures are always within 1 PSI of mine.)

Ken F in NM

Re: Is there any way to test if a tire gauge reads correctly?

Reply #6 – November 21, 2020, 11:02:13 am

Quote from: Kenneth Fears - November 21, 2020, 10:46:00 am

I believe that most good tire stores can test your gauge for accuracy. As noted, if you are within a few percentage points, that meets spec but can make a difference of a few PSI at rig tire pressures.

My digital gauge is consistent. By that I mean if I do three checks of a tire, I will get the same number, within 0.5 psi, all three times. I have set my tire pressures based on handling. At 65 front and 70 rear, my Michelins allowed a fair amount of drift. When I went to all steel Goodyears, they recommended 70 and 75, and I had no drift, zero. When I wore out the Goodyears, I could not get recent manufacture Goodyears so I went back to Michelins. I began experimenting with pressures to find a pressure with less drift. For me, that is 73 psi front and 78 psi rear. If I am within 0.5 PSI of those numbers I am good.

So, for me, I am not concerned about matching a paper number. I want consistency side to side, and I want optimal handling and control. If my gauge is off by 2 psi, I really don't care. (FWIW, when I get rig service, tire pressures are checked, particularly if they rotate the fronts. Their reported pressures are always within 1 PSI of mine.)

Ken F in NM

Since most of us never wear out a set of tires, adjusting the pressures to personal handling and control comfort levels, as long as the pressures are within safety guidelines, seems reasonable.

Chris

Re: Is there any way to test if a tire gauge reads correctly?

Reply #7 – November 21, 2020, 11:10:07 am

"(FWIW, when I get rig service, tire pressures are checked, particularly if they rotate the fronts. Their reported pressures are always within 1 PSI of mine.)"

The service shop where I go always checks and inflates the tire pressure as part of their multi-point inspection. After finding the readings other than I specified I now *insist* that they use my gauge when adjusting pressure!

Re: Is there any way to test if a tire gauge reads correctly?

Reply #8 – November 21, 2020, 11:22:54 am

I trust myself, not a shop, to check the pressures on the rig's tires after a (front) tire rotation and any service involving wheels or tires, including tire replacement. In my experience, there is too much variation among gauges (and who's reading them) to be confident that the numbers are accurate.

YMMV, as always.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #9 – November 21, 2020, 04:58:51 pm

Quote from: Joan - November 21, 2020, 11:22:54 am

I trust myself, not a shop, to check the pressures on the rig's tires after a (front) tire rotation and any service involving wheels or tires, including tire replacement. In my experience, there is too much variation among gauges (and who's reading them) to be confident that the numbers are accurate.

Oh yeah. I always tell them to leave my tire pressure as is. I have to watch them on an oil change as they want to inflate to max pressure. The pressures I run are what Michelin suggests for the weight I have on the axels. It must work as tire wear is about zilch.

My gauges are consistent, they just read differently at high pressure. I have been educated today that there standards that at least Jayco follows.

What do you mean by drift Ken? Wandering from a straight line? I have never noticed drift except on some sections of some interstates where I am sure the surface is biased in some way.

The tire gauges I have seen in tire shops sure as heck are not certified to any standard. I doubt those shirt pocket gauges or the ones of the hose are even close to being right.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #10 – November 21, 2020, 05:33:48 pm

When I take my rig to the Ford Truck Center, the service writer greets me with, "I know; don't touch the tires!"

Re: Is there any way to test if a tire gauge reads correctly?

Reply #11 – November 21, 2020, 06:09:41 pm

Don, to me, drift is if I am pressed by lateral wind from a passing big rig or a cross wind, my rig wanted to drift to the side. With a cross wind, no big deal, but a passing rig would push first the back to the right, which I would correct, then the pressure on the back would release and the front would want to drift right. If the road cross section was a bit non-uniform, the same thing would happen. As I added pressure, I started with the Michelin table values of 65 and 70, but noted that in each case, I was closest to those numbers but a bit above. So, I tried the next higher settings, 70 and 75. The improvement was dramatic. After that, I adjusted by 1 PSI at a time, until I felt the ride and handling were just about perfect. I settled on 73 and 78, per my gauge, as being perfect.

Ken F in NM

Re: Is there any way to test if a tire gauge reads correctly?

Reply #12 – November 21, 2020, 06:39:09 pm

Quote from: Kenneth Fears - November 21, 2020, 06:09:41 pm

Don, to me, drift is if I am pressed by lateral wind from a passing big rig or a cross wind, my rig wanted to drift to the side. With a cross wind, no big deal, but a passing rig would push first the back to the right, which I would correct, then the pressure on the back would release and the front would want to drift right. If the road cross section was a bit non-uniform, the same thing would happen. As I added pressure, I started with the Michelin table values of 65 and 70, but noted that in each case, I was closest to those numbers but a bit above. So, I tried the next higher settings, 70 and 75. The improvement was dramatic. After that, I adjusted by 1 PSI at a time, until I felt the ride and handling were just about perfect. I settled on 73 and 78, per my gauge, as being perfect.

Ken F in NM

I know nothing about drift physics but it would seem to me that the lower the tire pressure, the less drift there should be because tires at lower pressure would have more rubber on the road thus more resistance to drift. I'll let the experts dissect this conjecture.

Chris

Re: Is there any way to test if a tire gauge reads correctly?

Reply #13 – November 21, 2020, 07:02:49 pm

The tire shop I go to test their gauges. They showed me the test euuipment which looked like a large barometer. They tested my Michelin tire gauge, battery powered and recommended by the yahoo LD forum, for 80 and 30 psi. That was a few years ago and I should go back. Oh ya, my gauge was dead on. This shop supplies tires for commercial fleets and heavy equipment.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #14 – November 21, 2020, 08:45:12 pm

Chris, the drift doesn't come from the tread slipping. It comes from the sidewalls flexing. So, higher pressure, less side wall flex.

Ken F in NM

Re: Is there any way to test if a tire gauge reads correctly?

Reply #15 – November 21, 2020, 08:49:02 pm

Would that apply to this kind of drifting?

https://www.youtube.com/watch?v=IBXGO3QZFTQ

Re: Is there any way to test if a tire gauge reads correctly?

Reply #16 – November 21, 2020, 10:59:14 pm

Quote from: Chris Horst - November 21, 2020, 06:39:09 pm

I know nothing about drift physics but it would seem to me that the lower the tire pressure, the less drift there should be because tires at lower pressure would have more rubber on the road thus more resistance to drift. I'll let the experts dissect this conjecture.

A tire with a side load develops a slip angle in the tread that's on the road, and generally, the smaller the slip angle for a given side load, the better the stability of a vehicle in crosswinds and cornering. Higher tire pressures reduce the slip angle for a given side load. This link might help; there are surely articles with easier to grasp descriptions, so you might want to look further if it's interesting.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #17 – November 22, 2020, 07:26:29 am

Ken wrote: Don, to me, drift is if I am pressed by the lateral wind from a passing big rig or a crosswind, my rig wanted to drift to the side.

OK, I think we all experience that. Some people spend $ adding 'handling improvement hardware' to attempt to minimize it.
A few years back I concentrated on what I did when a big rig passed me and found I did a quick and not conscious movement of the steering wheel to compensate for the air pressure of the big rig. I am going to experiment when I get my new gauge and see if a pound more or less will make a difference for me. I am OK with it as it is, but maybe... Of course, I will need to drive on interstates and I seldom do that, so it may be a long time and by then I will have forgotten about it.

The rig feels every bump when the tires get inflated to 80 as tire shops and dealers want to do. So if it's a trade-off of a slight push by a big rig or a smoother ride, I will stay with smooth.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #18 – November 22, 2020, 08:08:24 am

Yesterday we were driving N on I-95 to Savannah with significant east winds causing a lot of drift to the left. Adding the ruts of the pavement it required steady attention to keep on track. My cold pressures were 60 front 75 rear. The TST monitoring showed 73F & 83R with warm tires. Passing trucks increased the side drift. I am not sure what would decrease this drifting. I do have the Bilstein shocks. Towing the Cherokee makes no difference. With the new 7.3L engine it’s hard to realize it is even back there.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #19 – November 22, 2020, 09:07:27 am

Don, it is definitely a balancing act between drift at lower pressures and a hard ride at higher. That is why I experimented, finally settling on pressures that worked well for me. These days, I have almost zero drift when a truck passes me.

Mike, I was experiencing the same in my first few years. Once I found the right pressure for me, drift was no longer a concern. The tire pressure recommendations, from Michelin and from me, are for cold tires.

If you want to experiment, you know the "feel" at your current pressures. Raise them by 5 PSI and drive. Is it better? Raise them a bit more, but not above 80. At some point, the handling will not be improved but the ride gets harder. That is too high. The "right" pressure will depend on how your rig is loaded, the kinds of roads you are on and your personal preferred "feel". Don likes a softer ride, because he is rarely on an interstate. Thus, his speeds are lower and he is less likely to have big rigs passing him, giving drift less chance to affect him. So, if you are mostly on local roads, a softer ride is likely to be preferred. If you are a highway driver, drift may become more of an issue than bumps, and you may want a harder ride.

Bottom line, tire pressure may be the biggest factor in vehicle handling. Before spending a pile of money on add-ons to improve handling, think about examining the effect of tire pressure changes.

Ken F in NM

Re: Is there any way to test if a tire gauge reads correctly?

Reply #20 – November 22, 2020, 06:23:20 pm

Ken wrote: I started with the Michelin table values of 65 and 70, .... I adjusted by 1 PSI at a time, until I felt the ride and handling were just about perfect. I settled on 73 and 78, per my gauge, as being perfect.

That's a substantial increase. 78 is as good as 80 and that's too bumpy a ride for me. I will stand pat. But, thanks for the explanation of how you got there.

Just my opinion but adding handling improvement hardware is snake oil to me.

PS, I sure wish the quoted text would limit itself to the text I high-lite rather than the whole post

Re: Is there any way to test if a tire gauge reads correctly?

Reply #21 – November 22, 2020, 06:49:19 pm

Quote from: Don Malpas - November 22, 2020, 06:23:20 pm

Ken wrote: I started with the Michelin table values of 65 and 70, .... I adjusted by 1 PSI at a time, until I felt the ride and handling were just about perfect. I settled on 73 and 78, per my gauge, as being perfect.

That's a substantial increase. 78 is as good as 80 and that's too bumpy a ride for me. I will stand pat. But, thanks for the explanation of how you got there.

Just my opinion but adding handling improvement hardware is snake oil to me.

PS, I sure wish the quoted text would limit itself to the text I high-lite rather than the whole post

PS, I sure wish the quoted text would limit itself to the text I high-lite rather than the whole post

Seems to me it used to. Above is copy and paste. I'll check it out.

Chris

Re: Is there any way to test if a tire gauge reads correctly?

Reply #22 – November 22, 2020, 08:10:33 pm

you could put chalk marks on the side walls and tread. If the marks on the side walls get rubbed off in the first 20miles or so you're very likely under inflated for the driving you do even if you within the normal PSI range. If the marks on the tread is not gone in the first mile you are over inflated, even if your with in the normal inflation limits for your weight. Ask a road racer about chalk on tires.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #23 – November 23, 2020, 07:16:07 am

Chalk marks are an excellent way to determine if the entire tire surface is "exposed". I use it on my Jeep. It only takes about 20 feet in parking lot to tell if any area of the tire is not wearing evenly. I have not used it on the LD as I am getting even wear.

Re: Is there any way to test if a tire gauge reads correctly?

Reply #24 – November 24, 2020, 11:22:03 pm

Quote from: Don Malpas - November 22, 2020, 06:23:20 pm

PS, I sure wish the quoted text would limit itself to the text I high-lite rather than the whole post

This worked like Don said, took all text.
However, I just go in an edit out the stuff I didn't want to have in the quote.
Jane

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