Tire Pressure gauges

[Mel Wilbur]

When comparing the reading on a new truck type digital tire pressure gauge I discovered that there was a 4 1/2 psi difference with the Dill truck gauge I had been using for years. I took both gauges to my local tire dealer that has the latest Hunter wheel balancing machine which includes a very accurate inflation system to find out which one was correct. Money well spent as it was the new digital. Fortunately, the Hunter technician happened to be there checking the calibration that day so I feel confident of the readings.

[lassen]

So Mel which is the right one, and which is the one that is 4 1/2 psi off?

Thanks....Jack

[bcope01]

Mel, did you check the gauges throughout the whole range of pressures (i.e., 10, 20, 30, 40, 50, 60, 70, 80 psi, etc.), or just a single pressure?

Bill

[Mel Wilbur]

Jack, the digital gauge was correct.

Bill, I checked 50,65, and 80psi and all were off the same 4 1/2 psi within 1-2% but of course that could vary with different gauges. My original gauge was reading low which meant that when I thought the rear tires were inflated at 80psi they were actually almost 85psi, not good.

[Tom and Jennifer Pierpan]

Mel, I would be interested in the name of the new truck tire digital pressure gauge that you purchased.
Tom

[Mel Wilbur]

Tom, the gauge is the Accutire MS5220 which I purchased from www.garage-toys.com I chose this particular one due to the straight line connection for the inner dual which works best for me as my outside duals are Alcoa aluminum with a different hole pattern than the original steel wheels.

[whemme]

I am with Mel. I also use a digital tire pressure gauge from the same company but a different model, in my case it is the Accutire MS-4000 that I have had for about three years. It has now been replaced with a newer model, the Accutire MS-4004B that has a built-in flashlight. My MS-4000 uses a red back lighted LCD readout whereas the newer MS-4004B model uses a blue back lighted LCD readout. As I recall I bought my MS-4000 unit in a Sears store.

The MS-4004B model is available for $26.99 from the same source that Mel bought his MS-5520 model (I think MS-5520 is correct; in his post, Mel has it as MS-5220). Direct website link is a follows: http://garage-toys.com/tiprgu.html

The older MS-4000 model that I have is still available from several online retailers one of which is Amazon.com which has it currently for a price of $19.99. Direct website link is as follows: http://www.amazon.com/Accutire-MS-4000- ... B00005AXI4

Both of these units offer a measurement range of 5 to 99 psi with readout in 0.5 psi increments, whereas the MS-5520 model Mel uses has a range of 5 to 150 psi. Specified accuracy is + or - 1% + 0.5 psi which means at 80 psi they will have a maximum error of 1.3 psi.

My experience in using the MS-4000 model (which I think would also apply to the newer MS-4004B model) is that due to the 45 degree head design, a person needs to accurately place the head onto the tire valve stem to get a good seal. This takes some practice and unless you accurately engage the two, air leakage occurs and the gauge responds with a 00.0 reading. Once you get a good seal without air leakage, you can remove the gauge and it will store the pressure reading for about 2 or 3 seconds for easy reading before going blank permitting you to make another measurement on the same or a different tire.

I also use a Advantage PressurePro tire pressure monitoring system on my Born Free and that system's pressure transmitters are also quite accurate. I have found that the MS-4000 pressure gauge reading agrees within 1.0 psi of the readouts from the PressurePro sensors in all 6 tire positions. The accuracy of these Accutire digital gauges are really quite good.

Below are photos of both the MS-4000 and MS-4004B products.

[camai7]

I don't recall the name but what about the valve caps that are set for a fixed pressure and show the color green when all is well and the color turns red when the tires are underinflated? Any one have an opinion on these?

[hrgermany]

These valve caps are called Tire Minders.The are made in Canada.They also make digital tire gauges.I am using those on my motorhome. At the beginning they some problems with pressure leakage, but this is now corrected. On my front tires I use 65#, on the rear tires 80#, and on my fill valves for the airbacks 50#. This makes it very easy to check for proper air pressure.
They can be bought directly from the company. Tel: 1-800-563-6679

Hans Rueckert
1995 BF 26RSB

[whemme]

As I understand it, the Tire Minders are valve stem cap replacements that will start indicating a low tire pressure when the pressure drops off somewhere in the 10 to 15% range. Depending on the particular model used, the indication is black in color when tire pressure is OK but will start to show yellow when a 10/15% pressure drop occurs. For the 80 psi units that you would use for the rear tires on a BF, that means that you would get a low pressure indication at around 70 psi. For the 65 psi units that you would use for the front tires, that means that you would get a low pressure indication at around 57 psi.

Other models have three color indications; green - OK, yellow - 10/15% pressure loss, and red - 25% pressure loss.

While this is better then nothing, I would still prefer that I know about a pressure loss before it drops that much. There are other similar products on the market. The photo below is of the Tire Minder Max product with three color indications.

[Roadtech]

This is an interesting tire guage. It eliminates the need to switch back and forth between the gauge and air compressor hose while inflating a tire. That has always been a pain when filling my tires. It comes in analog and digital. Has anyone had experience with one of these:

http://www.getagage.com/

[camai7]

Hope this question isn't too elementary. Since you are supposed to measure tire pressure when the tires are cold, do you simply determine the number of additional pounds cold, then add those same # of pounds when you drive to a gas station when the tires are no longer cold and show a different pressure than when they were cold?
I realize one could buy an air compressor, but if one doesn't have one, then what?

[whemme]

camai7,

Since I have an Advantage PressurePro tire pressure monitoring system in my Born Free coach, I can watch the pressure increase in each tire as they warm up from driving from a cold start. My experience is that you must drive the coach around 10 miles at cruising speed in order to get the tires up to their final operating temperature and the final pressure increase will be approximately 10%. So in my case where I run my rear duals at 75 psi initial cold inflation pressure, the pressure will increase to about 82 or 83 psi after being driven 10 miles or more.

So, my recommendation is if you need to add air to a tire that is already fully warmed up, I would inflate it to a pressure 10% higher than your desired cold inflation pressure setting.

[BonaProf]

Thanks for all the information on tire gauges and tire pressure. I enjoy reading the postings and thank all for joining in the discussion.

I tried an Accutire gauge a couple of years ago. It seemed to work well until one day I had no read out. I thought I would pop in a new battery but then discovered that I would have to return the device to the manufacturer and pay a fee. I decided it would have been cheaper to buy a new gauge and I went back to the old slide rule model.

I have noticed that some members have mentioned the psi that they try to maintain on their tires and noted it was different from what BornFree recommends. I have a E450 Ford, which Born Free says should have 50 psi in the front tires and 70 psi in the rear ones. They do show a "maximum psi" of 65 and 80. My question is what is best and why? Since this year's presidential campaign has commented on "properly inflated tires" saving gas, what's best to use when beginning a long cross-country road trip?

I must admit that I only check my tire pressure occasionally, usually before starting a long trip, and then kick the tires whenever I fill up with gas. How often do you check your tires?

Since I am obviously lazy, would the Tire sentry be a good choice for me? I would guess that you do not have your Tire sentry plugged in all the time since there are so many other gadgets that require cigar lighter use, but it would be good, I guess, to plug it in as you pull into a gas station since that would be more accurate than kicking the tires.

Lastly, while we are into air pressure, what is best for the air bag pressure? Born Free recommends 55 psi although it offers a wide range of possibilities from 10 to 90 psi. Here again, what is the theory behind increasing or decreasing air pressure? Does temperture or humdity matter or mountain driving versus flat land or the weight you are carrying? I usually try to follow the manufacturer's recommendation and measure the pressure in the morning before driving the RV, but there seems to be a science of psi that I am missing.

I would appreciate your sharing your reasons why a specific psi is better than another.

Thanks again!

[bfmc4fun]

Has any one used the led flashing valve caps. They are from Aviation Upgrade Technologies. www.aviationupgade.com (Snow in Colorado last nite) Bud