TMPS Variation From Guage

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camperAL

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Hi, I have an EZ TPMS and while I know there is variations in gauges and TMPS caps I seem to be getting about 5 or 6 lbs variation in the difference between the gauge and the caps. Check front passenger tire and it check exactly. Duals are a different story being off five or six pounds. Can the caps be adjusted? Do people take in account the difference and don't worry about it? I know this subject has been discussed to death, couldn't find an answer to my questions.

Do we have spell check on this new software?
 

DonTom

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Hi, I have an EZ TPMS and while I know there is variations in gauges and TMPS caps I seem to be getting about 5 or 6 lbs variation in the difference between the gauge and the caps. Check front passenger tire and it check exactly. Duals are a different story being off five or six pounds. Can the caps be adjusted? Do people take in account the difference and don't worry about it? I know this subject has been discussed to death, couldn't find an answer to my questions.

Do we have spell check on this new software?
I have many different types of TPMS. All ten of my motorcycles below have such, as well as my RV.

Usually, the alarms can be adjusted, but I have never seen any where the PSI could be adjusted. Just set your alarms for where you really want them, by using a decent gauge. Most do have alarms for under PSI that can be set, and some over PSI and temperature.

The accuracy varies. But I find most of mine to be within a few PSI of a decent gauge. Some are less accurate at higher PSI, which probably explains your duals.

You can get spell checkers for your internet browser that will work well here in this forum. I am using Chrome and misspelled words have a red line under them that I can right click on and see the words that are close that I can select to replace those underlined words with. What browser are you using?

Whatever it is, do an internet search for a spell checker for it. That way is better than a forum spell checker as it will work everywhere, as does mine.

-Don- Auburn, CA
 

John From Detroit

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I do not know the EZ system but I know this
When I had my rig weighed by Aweigh We Go (RV Safety Com) if I recall correctly)
They offered to calibrate my tire gauges.. I had pressure pro at the time and they told me that PP is traditional +/- one PSI or less that is to say very accrate.

Some "Stick" Gauges cab easily be 5 PSI or more off the mark.,
 

camperAL

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My gauge was purchased from a truck semi supply store and isn't the stick type. Figure it should be fairly accurate. My shop put pressure in the tire I check that matched my gauge. The gauge shows a near accurate on the duals but the TPMS caps are showing low compared to that. In fact all the duals are lower by about four or five lbs. and wondering if it could be the TPMS caps. Thought about switche the caps around to see what happens.

Thanks for the replies!
 

lavarock1210

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What is most important with a TPMS. That is if the pressures are Consistent. If you read the same pressure day after day at the same temperature then your TPMS sensors are consistent.

I have had a Pressure Pro and TST TPMS systems and both were very consistent.

The thing to watch for in a TPMS reading is any significant changes and more important that all tires report pressures that are very close assuming they were close when first aired up.

As for accuracy I just live with the difference knowing changes and differences between tires is what is important.

 

Mark_K5LXP

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"Factory" TPMS (in the tire) sensors read absolute pressure. Not sure if cap style sensors do this or not. Living at 5000ftASL I've just grown accustomed to the dash readings being 3-4PSI low. Per above I don't get too wound up over what the RV TPMS reports, it's only job is to let me know when things are going south.

Mark B.
Albuquerque, NM
 

DonTom

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One of my favorite types of TPMS are the ones that can be added to the Garmin GPS units. Very easy to set up, has high and low pressure alarm settings and is as accurate as any of my best tire gauges. They even show three digits instead of two. I can probably check my best gauges with this TPMS setup!

Replaceable sensor batteries.

Such as the TPMS in the Garmin 395LM which I own many of. Not cheap, as the pair of sensors are extra, and each one cost $70.00 ($140.00 per two wheel motorcycle) in addition to the GPS price. But we get what we pay for.

I do NOT know if any of the RV Garmin GPS units work with a TPMS.

But for my RV, I use one of these, as it shows PSI even when the RV has not been moved for months. It sends the TPMS only every few hours when parked, but every few minutes while driving. And instantly when a problem is detected. I use the flow-though sensors, which are less hassle and never have to be removed except for battery changes.

With the Garmin, the wheels have to rotate a couple of times for them to work.

-Don- Auburn, CA
 

camperAL

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Hi, First thanks for the replies. Forgot to mention that I loose the signal a lot when they are on for a time. Maybe need to change the batteries. My rig is only about 24 foot from the duels to the display. I tend to turn off the display for a short period of time then back on. Usually in about five minutes things begin to display again.

Sounds like I just need to relax or call the EZ place to find out why they are off the four or five pounds. Figure since the two front tires show a good reading that matches my gauge, the duels or part of them should be closer. Safe travels!

Al
 

DonTom

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I tend to turn off the display for a short period of time then back on. Usually in about five minutes things begin to display again.
That is perfectly normal. You have to understand how they work to understand why. TPMS are MUCH more complicated than most people realize.

In your case above, since your display was turned off, it has to wait for the next TPMS to be reported for each sensor. Five minutes is very FAST if that is all it takes for six wheels or more to report. But that time will vary greatly, because the sensors sending out the signals happen at different random times from each wheel.

And here is something everybody should know about external TPMS (and very few know this):

Say your hubcap comes off and breaks a TPMS sensor and now your valve stem is a half mile back on the freeway, with the TPMS still connected, but is now a half mile behind you. Your TPMS will show perfectly normal PSI for that missing TPMS sensor. And it can show as normal PSI for up to around ten minutes. IOW, no problem shown for a totally blow out tire for around ten minutes.

However, if you get a blowout and the TPMS sensor is still next to the RV, you get an instant (like a second delay at the most) that you have a tire problem.

BTW, you may ask me how I know. ;)

But really, I knew in advance that could happen, as I understand how they work. But it's way TMI to put in one of these forum messages.

But they are kinda tricky to understand as they cover many different possible scenarios, other than the missing sensor that is not seen at all for perhaps five or ten minutes. It is related to why it takes that long for your display to work. Waiting for the next digital signal from each TPMS sensor to be transmitted. So when out of range of the sensor, it has nothing new to display so it displays your last known PSI as if there is no problem at all.

But one other thing you should understand is that it takes a long time to get a TPMS update to the monitor unless something changes. So a sensor a half mile back on the road is no update as it is out of range, so all looks perfectly normal as your RV is probably shaking all over the road (depending on which wheel). The sensor DID send the instant update that you have a blowout, but no way can you see it from a half mile down the road.

-Don- Auburn, CA
 
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8Muddypaws

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I replace my batteries once a year. I get them from Amazon. Even name brands are inexpensive. I use silicon lube on the o-rings and have never had a problem.
 

DonTom

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I replace my batteries once a year. I get them from Amazon.
Me too. With some of these TPMS sensor batteries, Amazon or on-line elsewhere are the only places I know of where to buy them. Many of the ones used in my motorcycle TPMS sensors, AFAIK, can only be purchased on-line.

So it's best to have several extras laying around, such as with my CR1225's. But Amazon usually only takes a couple of days for small batteries.

-Don- Auburn, CA
 

Old_Crow

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So, what do you guys do with the sensors when you're parked for a while? I work managing campgrounds in the summer and I'm typically parked for 6 or 7 months at a time during the season.
 

DonTom

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So, what do you guys do with the sensors when you're parked for a while? I work managing campgrounds in the summer and I'm typically parked for 6 or 7 months at a time during the season.
With most types, there is no reason to ever remove the sensors. Most do not use any power until the wheels spin.

But there are exceptions, such as Pressure Pro. They always send out the signal if they move or not. But this way also has an advantage, they can be read at any time, such as being parked for weeks. But it is best that these are removed to help with the battery life. But even left on, they will last a long time (just not as long). Because the data burst transmissions are a short in length (less than a second) form the sensors (the transmitters) and are only sent once every few minutes. But these do not have user replaceable batteries and costs about the same as new sensors to have the batteries replaced by Pressure Pro. I think they have the oldest technology we can buy today.

IMO, best idea are the ones that send out the digital signal every couple of hours when the wheels do NOT move, but every few minutes when they do. Those will always give the readings and never have the need to be removed, except for when it is time for the user to replace the sensor batteries.

That is the type I have in my RV. This setup.


-Don- Auburn, CA
 

Old_Crow

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I never thought about the sensors going to sleep and not using power, thanks.
I bought the Tire Minder system. I read in the manual that if it's been sitting for a while you can "wake it up" and have it poll all the sensors at once when you get ready to start driving. I'll be checking my tires and prepping to move in a couple of weeks and plan on installing it at that time.
 
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