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TPMS - fireside chat


Bob Nodine

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Weather turned cold here a few days ago, 18 degrees at the house. We have three vehicles, all garaged, a 2013 Chevy Silverado Z71 CrewCab, a 2015 Ford CMax Hybrid, and a 2020 Chevy Sonic. Took the Sonic out Wednesday morning and soon got the low pressure alarm and the display told me the air pressure in each of the four tires. Keep in mind this is a vehicle that cost less than $20K. Took the truck out yesterday morning and got the same low pressure alarm and the vehicle shows me the air pressure in each of the four ties. Of course this was because of the large drop in temp from the garage to the outside. But it got me to wondering about my motorhome. I spend a lot of time keeping the TMPS on the motrorhome working by replacing batteries, etc. My three vehicles never give me any trouble and don't need battery replacement. Our coach is 15 years old and maybe this is not the case with new coaches, but why don't Class A motorhomes come from the factory with a built in TPMS like my other vehicles. I know you are going to say because the house and coach are built by different manufactures but surely they could solve that problem. From a safety stand point I think Class A coaches should have the TPMS built in just like my other vehicles.

 

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I wish my pressure pro receiver could use the car transmitters. The batteries  lasted 12 years on my pickup and I got a whole set of 4 for 40$ on Amazon. Instead I spend about 150$ a year on a few replacements that are supposed to last 5 years. I like the pressure pro other than that.

It has always been interesting that car tires are affected by temp change much more so than rv tires. The reason is atmospheric pressure is about 1/3 of the total pressure in a car tire but maybe only 1/7 of the rv tire pressure. So for the internal pressure to change by 10 percent to respond to a 10 percent change in absolute temp, the car tire pressure changes my more than twice the rv tire pressure.

If you were in outer space, the rv and car tires would change by the same. So, is there anything that can be done to make tire pressure less temperature dependent  ?

Bill g 06 dynasty

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I agree and have often wondered the same. You would think that the National Highway Transportation Safety Administration and the National Transportation Safety Board would be mandating it.

Some very early motorcoaches came with a built-in TPMS (sensor inside the wheel) called Smart Wave / Smart Tire that was excellent but I don't hear much about that TPMS any longer. Out of business most likely.

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4 hours ago, Hotrod said:

I wish my pressure pro receiver could use the car transmitters. The batteries  lasted 12 years on my pickup and I got a whole set of 4 for 40$ on Amazon. Instead I spend about 150$ a year on a few replacements that are supposed to last 5 years. I like the pressure pro other than that.

It has always been interesting that car tires are affected by temp change much more so than rv tires. The reason is atmospheric pressure is about 1/3 of the total pressure in a car tire but maybe only 1/7 of the rv tire pressure. So for the internal pressure to change by 10 percent to respond to a 10 percent change in absolute temp, the car tire pressure changes my more than twice the rv tire pressure.

If you were in outer space, the rv and car tires would change by the same. So, is there anything that can be done to make tire pressure less temperature dependent  ?

Bill g 06 dynasty

I wonder if inflation with nitrogen makes any difference.

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I'm thinking the sensors as currently manufactured cannot withstand the high pressure of the motorhome tires. Not sure if the demand would be enough to perfect such an animal and/or be politically correct if they could be mandated. I use the TST monitors and have been satisfied with them for the past 7 years....Dennis

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16 hours ago, Bob Nodine said:

Weather turned cold here a few days ago, 18 degrees at the house. We have three vehicles, all garaged, a 2013 Chevy Silverado Z71 CrewCab, a 2015 Ford CMax Hybrid, and a 2020 Chevy Sonic. Took the Sonic out Wednesday morning and soon got the low pressure alarm and the display told me the air pressure in each of the four tires. Keep in mind this is a vehicle that cost less than $20K. Took the truck out yesterday morning and got the same low pressure alarm and the vehicle shows me the air pressure in each of the four ties. Of course this was because of the large drop in temp from the garage to the outside. But it got me to wondering about my motorhome. I spend a lot of time keeping the TMPS on the motrorhome working by replacing batteries, etc. My three vehicles never give me any trouble and don't need battery replacement. Our coach is 15 years old and maybe this is not the case with new coaches, but why don't Class A motorhomes come from the factory with a built in TPMS like my other vehicles. I know you are going to say because the house and coach are built by different manufactures but surely they could solve that problem. From a safety stand point I think Class A coaches should have the TPMS built in just like my other vehicles.

 

 

10 hours ago, Paul A. said:

I wonder if inflation with nitrogen makes any difference.

NO. Dry air and nitrogen behave the same way. Most of what is claimed about Nitrogen is false. The main thing is it has no oxidizer and so cannot promote or feed a fire which is great on an aircraft but not so meaningful on a Moho.
 

Bill G

06 Dynasty

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I believe the real reason they do not include them is because of the varying pressure requirements of each coach according to weight as well as tires.

I used to run 105 - 108 lbs in my 275 tires. When I went to 295's I was able to lower the pressure to 100 lbs. In addition to varying pressures between coaches and tires comes the addition of toads and the need to monitor their pressures with a remote TPMS device. I think because of all the variables with our coaches the manufacturers just throw their hands up and say " let the owner worry about it ".

I am left trying to figure out how the manufacturers could install a permanent system that can be constantly programmed with our own personal variables. My Ram 2500 came from the factory with 60 psi set for the front tires and 80 psi for the rears. I just had my tires rotated at 10,000 miles and it took a while for the system to learn the front tire was on the rear and vice versus. Until then I had low pressure alarms. How the system learns the new tire positions and resets itself I haven't a clue.

So if they did install a permanent system at the factory we are still left with having to get a TPMS for our toads. I cannot speak for the rest of you but there is no way I will tow our show trailer or toad without a TPMS. If I am going to buy a TPMS for the toad I might as well get the sensors for the coach as well. JMHO. One last question...... What about the coach owners like myself who run Tyron bands ? How would those be installed over the top of an internal pressure sensor ?

 

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13 hours ago, Dennis H said:

.....I use the TST monitors and have been satisfied with them for the past 7 years....Dennis

I've also had TST (non color display and repeater in the engine bay of the coach) for several years, and basically happy.  One minor annoying "problem" I have is one to three or more sensors (coach and toad as well experience this) will suddenly (and almost simultaneously) set an alarm of high pressure. ... Like 545 lbs (coach) or 400 something (toad). It may go off for 3-5 minutes then read normal values again.  Strangely, many times it happens just as we slow down or turn into the campground ... I've sometimes joked "there's our arrival alarm ... Time to wake up dear...". Once in a while one may go off crossing an overpass.  It is not any particular sensor, and happens even with new batteries.  Sometimes it happens in the AM as I've turned the monitor on as I pack up sewer/water/elec, in which case the repeater is off as it is on a switched ignition circuit.  The coach is flow through sensors while the toad is the other (maybe why one kind reads 500 something lbs and the other 400 something). As the tire(s) couldn't just magically gain a few hundred pounds in an instant, I just press a button to silence it and continue onward...   Anybody else experience this weird behavior? 

 

 

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18 hours ago, amphi_sc said:

I've also had TST (non color display and repeater in the engine bay of the coach) for several years, and basically happy.  One minor annoying "problem" I have is one to three or more sensors (coach and toad as well experience this) will suddenly (and almost simultaneously) set an alarm of high pressure. ... Like 545 lbs (coach) or 400 something (toad). It may go off for 3-5 minutes then read normal values again.  Strangely, many times it happens just as we slow down or turn into the campground ... I've sometimes joked "there's our arrival alarm ... Time to wake up dear...". Once in a while one may go off crossing an overpass.  It is not any particular sensor, and happens even with new batteries.  Sometimes it happens in the AM as I've turned the monitor on as I pack up sewer/water/elec, in which case the repeater is off as it is on a switched ignition circuit.  The coach is flow through sensors while the toad is the other (maybe why one kind reads 500 something lbs and the other 400 something). As the tire(s) couldn't just magically gain a few hundred pounds in an instant, I just press a button to silence it and continue onward...   Anybody else experience this weird behavior? 

 

 

Yes, about a year ago or so I had exactly the same problem and called TST.  They told me it was a glitch and the monitors were picking up other TPMS's in the area.  They said they had 2 new monitors a black and white one and a color one that had different software and it would solve the problem, they even offered a discount for that reason.  I settled on the new black and white and they were right, it totally solved the problem, give them a call.  And the new monitor is worlds better than the old one.

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58 minutes ago, willbo777 said:

Yes, about a year ago or so I had exactly the same problem and called TST.  They told me it was a glitch and the monitors were picking up other TPMS's in the area.  They said they had 2 new monitors a black and white one and a color one that had different software and it would solve the problem, they even offered a discount for that reason.  I settled on the new black and white and they were right, it totally solved the problem, give them a call.  And the new monitor is worlds better than the old one.

Had the same problem this past summer when at a campground but cleared up once I got on the road. Called TST and the problem is caused by interference with others at the campground that have the new unit. Told TST that I use the system to check my pressures before I leave and having to remove each sensor to check manually is not acceptable. If your older monitor is less than 2 years old, TST will send you a new monochrome display AT NO CHARGE.

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On 12/5/2020 at 6:06 AM, Bob Nodine said:

Weather turned cold here a few days ago, 18 degrees at the house. We have three vehicles, all garaged, a 2013 Chevy Silverado Z71 CrewCab, a 2015 Ford CMax Hybrid, and a 2020 Chevy Sonic. Took the Sonic out Wednesday morning and soon got the low pressure alarm and the display told me the air pressure in each of the four tires. Keep in mind this is a vehicle that cost less than $20K. Took the truck out yesterday morning and got the same low pressure alarm and the vehicle shows me the air pressure in each of the four ties. Of course this was because of the large drop in temp from the garage to the outside. But it got me to wondering about my motorhome. I spend a lot of time keeping the TMPS on the motrorhome working by replacing batteries, etc. My three vehicles never give me any trouble and don't need battery replacement. Our coach is 15 years old and maybe this is not the case with new coaches, but why don't Class A motorhomes come from the factory with a built in TPMS like my other vehicles. I know you are going to say because the house and coach are built by different manufactures but surely they could solve that problem. From a safety stand point I think Class A coaches should have the TPMS built in just like my other vehicles.

 

Are you sure the cars don’t require battery replacement periodically? I found my 2017 Expedition does when I purchased new tires. 
 

BTW, do your cars have just the factory TPMS or add on aftermarket?

Ed           
’05 HR Ambassador 

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I would like to reply to several statements since I am the Lead Tech at TST.  First, those of you that have our system and it is pre-2016 and you are getting readings of 200-600+ PSI: There was a firmware update in late 2015. Any display manufactured before this update will read those high PSI numbers if the coach gets close to a unit that has one of our newer systems. What happens is the sensors will transmit through the newer repeater and that signal now has the firmware update. The older displays do not know how to interpret the updated signals when they receive them. They then display 200-600+ PSI. There is no way to update the firmware in the older displays. You just have to replace the display with a new color or monochrome unit. They are both backwards compatible with the order sensors. We are no longer giving away displays. That occurred a few times several years ago. The new displays are reasonably priced.

There is a manufacturer putting the TST TPMS internal sensors in their units. That is Forest River. They were the first to jump on the bandwagon over a year ago and we are now in many of the towable units. Other manufacturers are now talking with us to outfit their new units. Dynamax is also putting our external sensors on their products. I agree, with a Class A motorhome, it should be a no brainer to include a tire pressure monitoring system in it from the factory as a safety measure!

Jim G
206 Camelot
TST Rep

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Jim

I also have a fairly new TST color monitor.  I find the monitor impossible to read with daylight glare.  The blue numbers on the black background do not provide enough contrast for me to differentiate the values.  I have not found any way to change color combinations or increase the contrast.  Have I just missed some adjustment somewhere.  (I can no longer find the instruction booklet.)  Thanks.

 

Richard

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Richard,

We are coming out with a visor for the color (or monochrome) display. Tests show that this helps a lot with the screen readability. I believe it will be ready in the next few weeks. Not sure the price, but it will be low. That will help. You can not change the color combination on the display.

JimG
2006 Camelot

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On 12/7/2020 at 9:00 AM, saflyer said:

Are you sure the cars don’t require battery replacement periodically? I found my 2017 Expedition does when I purchased new tires. 
 

BTW, do your cars have just the factory TPMS or add on aftermarket?

Ed           
’05 HR Ambassador 

Well ED, I don't know, in fact there is a lot I don't know as I am finding out. All I can tell you is that my three vehicles have built in tire pressure monitoring from the factory. The readings display through the information system built into the instrument panel. Both my CMax and Sliverado have had tire replacements and if they replaced batteries when putting on new tires they did not mention it to me or charge me for them. I purchased a 2007 Ford SportTrac new that I gave to one of the daughters about two years ago. It has a built in tire pressure monitoring system that still works at over 200,000 miles. That vehicle has had a number of tire replacements and after each tire change you would have to drive it for a few hundreds yards to clear out the low pressure alarms.

My motorhome has an aftermarket tire pressure monitoring system and we also attach sensors to the toad when we use it behind the motorhome.

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There are many different OEM TPMS variations.  For the most part, you cannot just replace the batteries.  The battery is molded into the valve stem assembly.  Prices for replacement sensors are all over the map.  I have heard some GM ones costing $150 each.  Of course the dealer will tell you that you need to replace all 4, so with labor it can approach $800.  
              
I did a little research and found that TPMS batteries last anywhere from 3-10 years.  That info was no help.  I know that in 2019 a sensor went bad in my 2009 F150 and the Motorcraft part was around $45.  I purchased an aftermarket set of 4 on eBay for $20.  Took the truck to Walmart and they installed the replacement for free.  The reason they did it for free was because they advertise a $29.95 TPMS replacement service.  Well, I had dropped the truck off there a week earlier and after waiting all day they called and said they could not replace my sensor because it was “special “.  Apparently, there are some “one size fits all” solutions out there.

My final thought:  I would much rather have the aftermarket system where the sensors thread onto the valve stem.  They are cheap, you can easily replace the battery and you don’t have to take it to a tire shop and have the tire broke down to work on the sensor.  The downside is they are easily removed - meaning someone could steal them.  When the Feds mandated TPMS in 2008 I thought it was a great thing.  I now realize it was yet another thing that only the dealer or a shop could work on, as not many do it yourselfers have a means of dismounting tires.

Dan 

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Batteries for the sensors are an interesting subject. The reason our TPMS batteries now only last between 1.5 and 2 years is that they are constantly transmitting a signal to the display. An OEM system transmits less frequently and can therefore go a much longer time before they have to be replaced. This is why we went from the 510 system, with non-replaceable batteries, to our current 507 system so our customers can replace the batteries and not have to send them in to us. This basically made the 510 system obsolete in a relatively short time.

As far as theft goes, we do not see people stealing sensors. If you do not have the rest of the system, they are worthless. Most of the time they are not even noticed on the valve stem. We do provide a sensor "theft deterrent" to help keep honest people honest! Actually, we have had more displays stolen off the dash because they think the display is a GPS unit and rip it off.

If the battery is depleted in the sensor, our system does show a warning and the display will beep. We want to let you know that the tire will not be transmitting data and, if a problem occurs with that tire, you will not know it. Very important to replace the battery as soon as possible so you are protected.

JimG
2006 Camelot
TST Rep

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I rotate my own tires on our vehicles and wonder how the system knows the tire position. Just the other day when I got the two low pressure alarms the display matched the position with the lowest PSI. It is possible on the truck that I had landed all four tires back to the original OEM position but I have only rotated the tires once on the Sonic so not possible there. I rotate using the modified X method and the front tires move to the rear on the same side and the rears move to the front reversing sides. Over the years we have been plagued with tires making a noise after 7 or 8 thousand miles because they develop a scallop. Once this happens no amount of rotating with stop the noise and the only solution is to purchase new tires. For that reason I rotate tires every 5000 miles. Another hard lesson learned is that on vehicles with stability control - which is almost every vehicle sold now- you must replace all four tires at the same time. Any difference in diameter between the front and back tires will drive the control system crazy. 

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I would also like to rotate my tires to alleviate a slight heal/toe wear pattern.  However, to reverse this wear pattern it would require putting the drive tires in a position where they will rotate in the opposite direction from where they were first installed.  I have always been told that radial tires should be rotated so they will turn in the same direction (front to back same side on a car).  Does this logic carry over to the heavy duty truck tires on our motorhomes?  Thanks for any insight you might have.

Richard    

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47 minutes ago, hex_nut said:

I would also like to rotate my tires to alleviate a slight heal/toe wear pattern.  However, to reverse this wear pattern it would require putting the drive tires in a position where they will rotate in the opposite direction from where they were first installed.  I have always been told that radial tires should be rotated so they will turn in the same direction (front to back same side on a car).  Does this logic carry over to the heavy duty truck tires on our motorhomes?  Thanks for any insight you might have.

Richard    

That may vary by tire model and manufacturer. I believe with the Michelin xza2’s that I run it is not supposed to matter. But the only rotation I have ever done is to retire steer tires based on time and put them on the right drive wheel as a pair. 
 

bill g 06 dynasty

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7 hours ago, hex_nut said:

I would also like to rotate my tires to alleviate a slight heal/toe wear pattern.  However, to reverse this wear pattern it would require putting the drive tires in a position where they will rotate in the opposite direction from where they were first installed.  I have always been told that radial tires should be rotated so they will turn in the same direction (front to back same side on a car).  Does this logic carry over to the heavy duty truck tires on our motorhomes?  Thanks for any insight you might have.

Richard    

Modern radial tires can be moved to the opposite side of the vehicle and rotated in the reverse direction. By using the modified X pattern each tire will spend time at each wheel position of the vehicle and eliminate the heal/toe wear pattern. We are talking about passenger and light truck tires here. I don't know about the heavy duty tires and never rotate tire on the motorhome.

 

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On 12/7/2020 at 12:48 PM, ncjimgr said:

I would like to reply to several statements since I am the Lead Tech at TST.  First, those of you that have our system and it is pre-2016 and you are getting readings of 200-600+ PSI: There was a firmware update in late 2015. Any display manufactured before this update will read those high PSI numbers if the coach gets close to a unit that has one of our newer systems. What happens is the sensors will transmit through the newer repeater and that signal now has the firmware update. The older displays do not know how to interpret the updated signals when they receive them. They then display 200-600+ PSI. There is no way to update the firmware in the older displays. You just have to replace the display with a new color or monochrome unit. They are both backwards compatible with the order sensors. We are no longer giving away displays. That occurred a few times several years ago. The new displays are reasonably priced.

There is a manufacturer putting the TST TPMS internal sensors in their units. That is Forest River. They were the first to jump on the bandwagon over a year ago and we are now in many of the towable units. Other manufacturers are now talking with us to outfit their new units. Dynamax is also putting our external sensors on their products. I agree, with a Class A motorhome, it should be a no brainer to include a tire pressure monitoring system in it from the factory as a safety measure!

Jim G
206 Camelot
TST Rep

Jim, 

I have an older TST system.  Bought it back in the early 2000s so it's 15+ years old.  I never experienced the false reading problem in all this time.

Will the new TST color monitor work with my sensors?

Edited by rpasetto
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