Tire pressure monitor systems

[hammer55]

your the expert, the video on their web site says that you set the low pressure warning to 10 psi below the set psi, and the high 20 psi above the set pressure,

https://youtu.be/5-KsnSUM2F8

now if your set psi is 90 and the max tire pressure on the side wall says 100psi, and then the temperature exceeds the max pressure of the side wall, then I am not understanding, if the tire can handle a max pressure of 175 psi, why do they have it stamped on the sidewall 100, as you can see I am not a tire expert, I need to read more about this pressure stuff on your site I guess, thanks for the info

Originally Posted by Tireman9

Thanks for the additional info. Lets set aside the pressure measurement question and assume the tires were set to 90.

You said you set the tires low at 80 or high at 110. I do not understand why. With a motorhome you should always have the tires set to no less than the minimum pressure needed to support the heavier end of each axle based on actual measurements. I have covered this a number of times in my blog. I also recommend that cold inflation pressure be set to that minimum inflation +10% and rounded up to the next 5 or 10 psi increment to make measurement and remembering pressure easier.

We know that if we follow the math of 'Gas Law" that tire pressure will change about 2% for each change of 10F. So if your tires were running at Ambient + the normal 20 to 60F range in temperatures, we could expect a 4% to 12% increase ion pressure. I have seen some reports of a pressure increase of as much as 15% but that is the exception in my experience and may be a function of improper load measurement or higher operating speed.

A review of the TST manual shows the high pressure warning to be at 175 psi from factory so have no idea why your unit is giving a high pressure warning at 110psi as you said in post #36.

RE tire capability. Your LR-G tires should handle 175psi with no problem as long as they have not been damages, run with low inflation or improperly repaired.

Suggestions:
1. Set the high pressure warning to 175 psi
2. Confirm your measured loads and that 90psi is at least 10% greater than the minimum shown for the measured load per the information in the Load tables.

[Tireman9]

Originally Posted by hammer55

your the expert, the video on their web site says that you set the low pressure warning to 10 psi below the set psi, and the high 20 psi above the set pressure,

https://youtu.be/5-KsnSUM2F8

now if your set psi is 90 and the max tire pressure on the side wall says 100psi, and then the temperature exceeds the max pressure of the side wall, then I am not understanding, if the tire can handle a max pressure of 175 psi, why do they have it stamped on the sidewall 100, as you can see I am not a tire expert, I need to read more about this pressure stuff on your site I guess, thanks for the info

I watched the video and I do not agree with the suggestion to set the low pressure warning below the pressure needed to support the load. This could result is driving on an overloaded tire for days which could do damage.

I do suggest you review my blog for more details and background on tire load and inflation, I also have a post on Minimum vs Maximum inflation.

But the short answer is
Set the low pressure warning on the TPMS to the minimum pressure needed to support the measured load.

Select your cold "set" pressure to that minimum +10% and round up to next 5 or 10 psi. So if you need 80 to support the load your set pressure would be 88 rounded to 90. If you needed 85 to carry the load the set pressure would be 94 rounded to 95

I am more concerned with high temperature than high pressure as tires are designed to tolerate pressure increase due to operation. Most TPMS use 70c or 158F as the high temperature warning level and I am comfortable with that.

With your truck tires, I would be comfortable with a pressure increase of 25 or maybe 30 psi

[lbrjet]

If you are comfortable with a max pressure increase of 30 for his tires, why tell him to set the high pressure at 175? You are confusing even more than usual.

The 100 psi rating for your tire is the maximum cold tire inflation number, in your case above for 68 degrees. Tires are designed to handle an increase beyond this pressure when heated up. I have never seen a tire company publish exactly what 'beyond' means, but a 10-20 percent increase could probably be considered normal. A combination of sun, rolling resistence, and ambient temperature increase all influence the temperature increase in your tire and hence the pressure increase. You tire is not going to blow at 110 and I would be surprised if you see it that high very often.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[Tireman9]

Originally Posted by lbrjet

If you are comfortable with a max pressure increase of 30 for his tires, why tell him to set the high pressure at 175? You are confusing even more than usual.

The 100 psi rating for your tire is the maximum cold tire inflation number, in your case above for 68 degrees. Tires are designed to handle an increase beyond this pressure when heated up. I have never seen a tire company publish exactly what 'beyond' means, but a 10-20 percent increase could probably be considered normal. A combination of sun, rolling resistence, and ambient temperature increase all influence the temperature increase in your tire and hence the pressure increase. You tire is not going to blow at 110 and I would be surprised if you see it that high very often.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

Point I am trying to make is that they can set the high pressure warning much higher than the 110 as suggested by TST in their Mar 27 2012 video. I have no idea what TST was thinking about by suggesting that running under-inflated when they instruct users to set the low pressure warning at 10 psi below the tire set pressure". I also do not know why the High pressure TST suggested resulted in a warning signal.

I see little reason for any high pressure warning as I do not know how you can get that without already exceeding the high temperature warning of 158F.

I have contacted Hammer55 and offered to call and talk them through tire pressure setting.


There are a number of posts on this forum I have written outling exactly how to learn what pressure to set your tires to and what to set the TPMS at. I also have over 200 posts on my blog with probably over 40% having something to do with load and pressure.

I seem to keep writing the same advice over and over as apparently people are not willing to do a few basic searches on this or other similar forums and look at the qualifications of the poster to see if the questions they have are already answered.

I have also contacted TST and asked what they were basing their pressure warnings on.

I do not understand your reference to 68 degrees in my example. It does not matter what the ambient temperature is. If you have established you need xx psi to support your measured load and you have added my suggested margin the resulting number is the pressure I would suggest for your tire set pressure. There are no calculations or further adjustments of pressure that are based on ambient temperature.

Note my 100 psi example is not the inflation I am suggesting for hammer55 but just an example for calculation example.

I do get a bit frustrated at time. I know that if I write something someone will more than likely take information out of context and they may end up having a tire failure.

This information should be provided by evert RV dealer but it isn't. GY and Michelin each have RV specific publications and even video on RV tire inflation but again few seem willing to read these information books. I have traveled across the US at my own expense offering seminars on RV tire application and I spend many hours each week responding to questions on a number of RV forums. Just this morning I even contacted Tire Rack and pointed out another error I discovered in the web site.

Sometimes the wife asks why I bother. Sometimes I agree and wonder.

[lbrjet]

The first sentence was for you Tireman and the rest for for the poster you suggested 175 degrees to. He set his 100 lb max tires at cold 68 degrees. Maybe you have to many threads in your brain to remember 2 hours ago.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[Tireman9]

New info.
Just heard back from TST. Twice they hung up on me because the blog I write, that is owned and run by RVTravel.com has a competitor TPMS company as a sponsor.

It is their position that I am bias so they are not willing to discuss, in a civil manner, the question of why they are advising customers set the high and low pressure warning to "-10psi and +20 psi".
What is interesting is that the first person I talked with, before I identified myself as a tire engineer and that I write a blog on RTire Safety, insisted that the video said -10% and +20% and that even -30% was reasonable in hot temperatures.
She was reasonable and asked for my name and number so someone could call me back to discuss the question.

It was a man that called back. said he thought my "Tiretraker blog was nice looking" but he had no interest in talking with a competitor and immediately hung up on me before I could say a word,

I returned his call and he said that because I "worked for a competitor" I was bias and again hung up on me.

IMO TST appears to not be interested in helping customers understand proper setting of their TPMS if they would have to talk with a tire engineer that writes a blog that is posted on a site owned and run by another individual.

Maybe my hearing is off. When I listen to the Youtube
https://youtu.be/5-KsnSUM2F8
at about 3:16 and again at 3:50 I seem to hear advise to set the the pressures to a psi not a percent.

But maybe because I don't work for TST my hearing must be off.

[lbrjet]

The high pressure on my Tire Traker from the manual is 25 percent. The max I have reached is 22 percent so that alarm has never sounded so I don't know if it actually works. The manual says 15 percent on low pressure and I have tested that this works.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[lbrjet]

When I set mine up I set the psi to 68.3 (instead of 65) so it would would alarm at 58 instead of 55 which is closer to 10 percent.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[Lincoln20]

In response to Tireman and the TST dispute. I guess my first question is do you work for, or are you associated with Tire Traker in any way? Do you feel any obligation to Tire Traker? I went to your site to see what may have made the TST folks question your call. At the top of your site is a massive banner that says "This Blog is Sponsored by Tire Traker". IF you are going to be a nuetral party then you may want to drop the sponsorship, or at least go with sponsors not directly associated with what you are disputing on your posts. Im not saying that to be ugly, I happen to think your blog is useful, but getting into it with other TPMS systems in a public forum when you are sponsored by Tire Traker just doesnt seem cool. If you follow TPMS then you have to know that TST is a leader in this space.
Having said that, I believe all TPMS say to set your parameters above and below the suggested cold tire rating. Is anyone suggesting that if the exact number the tire should be at is 90 psi then that is where the low parameter is? The alarm would be driving you nuts on cold mornings.
Anyway, RVing is supposed to be fun, this post is a bit stressful, I think I will move on to another one.

[Tireman9]

typo in post $46
-30 should be +30

[Tireman9]

Originally Posted by Lincoln20

In response to Tireman and the TST dispute. I guess my first question is do you work for, or are you associated with Tire Traker in any way? Do you feel any obligation to Tire Traker? I went to your site to see what may have made the TST folks question your call. At the top of your site is a massive banner that says "This Blog is Sponsored by Tire Traker". IF you are going to be a nuetral party then you may want to drop the sponsorship, or at least go with sponsors not directly associated with what you are disputing on your posts. Im not saying that to be ugly, I happen to think your blog is useful, but getting into it with other TPMS systems in a public forum when you are sponsored by Tire Traker just doesnt seem cool. If you follow TPMS then you have to know that TST is a leader in this space.
Having said that, I believe all TPMS say to set your parameters above and below the suggested cold tire rating. Is anyone suggesting that if the exact number the tire should be at is 90 psi then that is where the low parameter is? The alarm would be driving you nuts on cold mornings.
Anyway, RVing is supposed to be fun, this post is a bit stressful, I think I will move on to another one.

RE sponsorship and my integrity.

I have no say in who sponsors the blog I write for. I do not own the blog. I just was asked to write for it by RVTravle bookstore. I receive no commission relative to sales of TPMS. If you read my post "Best TPMS" you will not see me mention any brand. You will be hard pressed to see me say "Tire brand X" is the best or brand or y is the worst.

I do not work for and never have worked for any company that makes or sells TPMS. I will admit to talking with a guy that sells Tire Traker when I am giving seminars at RV Conventions. I have also talked with vendors of a variety of products so maybe that means I cannot offer any un-bias opinions?

I have no problem with people using TST brand or Pressure Pro or Tire Minder. I bought and installed my personal TPM system in 2008 before I started to write my blog in 2011.

I do object to it being implied that my technical opinion is for sale to the highest bidder.

I will say that ANY TPM system should spec the warning to go off when the tire is overloaded. I agree with the general warning of 158F for the max running tire temp from ANY TPM.
The only reason I contacted TST was to try and get clarification on hammer55 high pressure warning level of +20 psi. If a user gets a false warning then IMO the user may start to ignore warnings from the TPMS which would not be a good situation.

Instead of providing an answer to my question of why they thought -10 to +20psi was a good range, I felt my integrity was called into question. The fact that they thought the blog was "the TireTraker blog" suggests they did not look at more than the heading. They refused to even talk to me. They did provide conflicting information i.e. the pressure warnings were to be -10% to +20% or sometimes +30% of base line pressure. Listen to the Youtube and tell me what they advise then come up with an answer for what hammer55 should do.

I have worked with engineers from two other major tire companies and I worked at the 3rd of the big three. We had no problem discussing technical issues with each other and agree on many topics.

In my carer I worked with "secret" sensitive information from GM, Ford, Chrysler, Toyota, Honda, Fiat, Saturn, BMW and Subaru but was never criticized for not offering the best un-bias technical advice I could. When working with different teams on Indy car tires no one questioned my integrity then either.

If I have said something incorrect concerning tires or TPMS or valves, I will gladly issue an apology and retraction. All I ask is that facts and data be presented to support the claim I am wrong.

Lincoln, if you want to set up a blog with no sponsorship and want me to write for you all you need to do is ask. Let me know the URL and when we will go public. Alternately if you know a non tire product related company that would like to sponsor my blog I can put them in contact with the blog owner.

FYI IMO Tire Traker is wrong for suggesting the normal low pressure warning should be -15% below baseline without providing more information on how to properly select the baseline pressure. They were in business before they started to sponsor the blog so I have no authority over their practices. All I can do is talk with them and try and convince them to do a better job.

In my more recent posts about TPMS I am suggesting the warning pressure should be the pressure at which the tire becomes overloaded based on the Load Inflation table and the measured tire load of the tires on the RV. If anyone can provide data as to why this suggestion is wrong I am more than willing to listen to the argument as long as there is data to back up their position.

I really wish this thread had not degenerated but I am still looking for data that suggests that running at -10psi or -10% inflation is OK for the tire.

[hammer55]

well sorry for taking this post down, was just wanting to know the max pressure the good year tire was safe to run, as far as the low pressure, well , the is just a generic number to me, I want to keep them at the target psi for load, but what I do not want to do is stress the tire sidewall with a exorbitant amount of pressure to blow the tire, if the tire can handle 30psi over the sidewall pressure stamped on the tire, then I am fine with that, I was just not happy with the alarm sounding which I set the tire monitor to 20psi as recommended by tst video, so with my ambient temp in the am, I set my tires at 90psi, and the tst read anywhere from 89 to 92 psi( which I am not sure of the +- accuracy of the tst507, but it was close, anyway it alarmed at 110 to 111 psi, as long as it is safe to run at +30 psi then I am good running at 110psi, I was trying to read more about GY tires yeaterday, and will read more this morning, and the news always distracts me too,,,,lol
thanks to all who responded trying to direct me in this,

[hammer55]

here is what this dumb guy that I amshould have done, is set my high pressure at 20PSI over the sidewall stamped max pressure, and been done with it, I should have thought it through, but I didn't, oh well live and learn, still like all the info, and still reading, but most of GY site info is very vague to say the least

[Tireman9]

Tire max pressure. Not the pressure related to the tire load, just the static max pressure.

If the tire is sound and has never been damaged, punctured or repaired i.e. like new,
it is my experience that tires can handle two times the maximum pressure molded on the tire sidewall or 200 psi WHICHEVER IS LOWER.

It should be noted that this is static pressure measured on special test wheels. It is also not the pressure used to "seat" tire beads which is identified on the sidewall of many tires. This 'SEATING" pressure is many times significantly lower than the load max pressure. It may be in the 35 psi range. Improperly seated tires ( not lubricated or not firmly and concentric seating against the wheel) can fail at rather low pressure.

There are videos of tire explosions where a tire does explode. In some cases at less than sidewall max but this is usually related to a tire that has been run with less than 80% of the pressure needed to support the load.

Despite what some think tires simply do not "blow out" from normal pressure increase seen when a tire is run down the road. Sidewall failures are almost always the result of fatigue of the sidewall due to operation while significantly under-inflated for the load on the tire. The other time for a sidewall to fail is after (seconds to weeks) some impact such as hitting large road trash or large pot hole.

[lbrjet]

"still looking for data that suggests that running at -10psi or -10% inflation is OK for the tire."

It all depends on the leeway you have between your actual load and the max load for the tire. Run a load range higher than needed for actual load like I do and it is fine.


2010 F250 5.4L 3.73
2011 Flagstaff 831FKBSS
Equal-i-zer 4pt 12K

[KingFisher]

The more I read about tpms the more confused I become.

We were taking the Windjammer 3001W I bought to take to Florida on a local camping trip tuesday just to check it out, about 90 miles away. 15 miles in a tire exploded and tore up the side of the trailer. After much difficulty since tractor trailer driving idiots couldn't get in the middle lane of a 3 lane northbound interstate and kept flying by me right next to my trailer at 70+ mph I finally got the tire changed and the Windjammer back home.

We moved our clothes and food over to our sunset trail and went ahead with our trip.

Now that I'm back I'm obviously going to get 4 brand new tires for the Windjammer. Been thinking about tpms since I drove half a mile without hearing anything after the tire exploded, my Labrador was panting heavily in my ear and I had the radio on.

I'd hate to invest in a ton of money since I'll be taking this trailer on maybe one local trip after I get if fixed and new tires, and then I'll be pulling it to Florida and it will sit there year round.

Is there a good dependable unit that I can remove easily once I park the trailer in florida, then bring back with me and put it on the sunset trail 250RB?

[Delco Bobby]

Originally Posted by Tireman9

RE sponsorship and my integrity.

I have no say in who sponsors the blog I write for. I do not own the blog. I just was asked to write for it by RVTravle bookstore. I receive no commission relative to sales of TPMS. If you read my post "Best TPMS" you will not see me mention any brand. You will be hard pressed to see me say "Tire brand X" is the best or brand or y is the worst.

I do not work for and never have worked for any company that makes or sells TPMS. I will admit to talking with a guy that sells Tire Traker when I am giving seminars at RV Conventions. I have also talked with vendors of a variety of products so maybe that means I cannot offer any un-bias opinions?

I have no problem with people using TST brand or Pressure Pro or Tire Minder. I bought and installed my personal TPM system in 2008 before I started to write my blog in 2011.

I do object to it being implied that my technical opinion is for sale to the highest bidder.

I will say that ANY TPM system should spec the warning to go off when the tire is overloaded. I agree with the general warning of 158F for the max running tire temp from ANY TPM.
The only reason I contacted TST was to try and get clarification on hammer55 high pressure warning level of +20 psi. If a user gets a false warning then IMO the user may start to ignore warnings from the TPMS which would not be a good situation.

Instead of providing an answer to my question of why they thought -10 to +20psi was a good range, I felt my integrity was called into question. The fact that they thought the blog was "the TireTraker blog" suggests they did not look at more than the heading. They refused to even talk to me. They did provide conflicting information i.e. the pressure warnings were to be -10% to +20% or sometimes +30% of base line pressure. Listen to the Youtube and tell me what they advise then come up with an answer for what hammer55 should do.

I have worked with engineers from two other major tire companies and I worked at the 3rd of the big three. We had no problem discussing technical issues with each other and agree on many topics.

In my carer I worked with "secret" sensitive information from GM, Ford, Chrysler, Toyota, Honda, Fiat, Saturn, BMW and Subaru but was never criticized for not offering the best un-bias technical advice I could. When working with different teams on Indy car tires no one questioned my integrity then either.

If I have said something incorrect concerning tires or TPMS or valves, I will gladly issue an apology and retraction. All I ask is that facts and data be presented to support the claim I am wrong.

Lincoln, if you want to set up a blog with no sponsorship and want me to write for you all you need to do is ask. Let me know the URL and when we will go public. Alternately if you know a non tire product related company that would like to sponsor my blog I can put them in contact with the blog owner.

FYI IMO Tire Traker is wrong for suggesting the normal low pressure warning should be -15% below baseline without providing more information on how to properly select the baseline pressure. They were in business before they started to sponsor the blog so I have no authority over their practices. All I can do is talk with them and try and convince them to do a better job.

In my more recent posts about TPMS I am suggesting the warning pressure should be the pressure at which the tire becomes overloaded based on the Load Inflation table and the measured tire load of the tires on the RV. If anyone can provide data as to why this suggestion is wrong I am more than willing to listen to the argument as long as there is data to back up their position.

I really wish this thread had not degenerated but I am still looking for data that suggests that running at -10psi or -10% inflation is OK for the tire.

I think you perform an excellent service and offer much needed advice.

I appreciate your efforts.

We could eliminate all sponsorship and go to paid subscriptions but few would be willing to do so.

Thanks,

Bobby

[Tireman9]

I want to help KingFisher while at the same tiime avoid the label of being bias so I will not post a link to my blog but will offer the following.
"Friday, May 23, 2014 What is the "Best" TPMS

Yes along with What is the "best" brand tire or Best RV or maybe even the Best pizza, people seem to think that there is a single answer to almost every brand selection that everyone will agree on.

As an engineer I feel that just as Henry Ford was wrong when he decided everyone would want a black car, there is seldom a "Best" anything that is the best for everyone. However, having said that, you probably still would like some guidance in selecting a TPMS.

NOTE: I am certain that ANY brand TPMS is better than not having a system.

So here is what I suggest you use for a selection system. I think this will be a good system to use even as the technology moves forward.

I think there are four major categories to use when shopping for a new or replacement system.

1. Performance: What does the system do and how well does it do it?

2. Cost: This includes more than just the initial purchase price as there may be the cost of installation and what about the batteries? When looking at cost I suggest you do a comparison based on the expected replacement cost of replacement sensors if you can't install batteries yourself.
Example - non-replaceable batteries last 5 to 6 years so include the cost of a set on new sensors vs the cost of replacing batteries every two or three years. (three sets at $1.50 per battery for example). Selection of an internal mount system will include the cost of the initial dismount and mount and balance of tires and a second dismount, mount and balance when the sensors need replacement a few years later. This cost could exceed the cost of a TPM system so is an important consideration

3. Warranty: This may be the easiest as I prefer a longer warranty to a shorter one. I believe that car manufacturers do a much better job of designing and building their product than does the RV industry. Given the prevalence of 3, 5 and even 10 year warranties for cars vs the normal few months offered by those selling RVs products with longer warranties are more likely to be better than those with short warranties.

4. Support & Service: How easy is it to contact the seller? Are there videos on YouTube showing how to install and program your TPMS?

Items 2 through 4 are best left to you to learn and investigate. Some people don't care about YouTube videos and others don't worry about warranties, so lets focus on "Performance"

Here are some questions to consider:
a. Does the system "talk" to your on-board video display? This may lock you into one brand to the exclusion of all others.

b. Accuracy: Some people are overly concerned with the accuracy of the TPMS. Personally I have observed that after setting my tire cold pressure using by calibrated digital hand gauge I see that the TPMS gives slightly different numbers for almost every tire BUT the difference is usually only a couple psi. While this may be measurable I don't consider it meaningful. You might want to review the concept of Measurable vs Meaningful. You could also review my comparison of two systems HERE.

c Temperature vs pressure checking. Most aftermarket systems will signal both pressure and temperature. Some people think temperature is very important but as a tire engineer I believe that if you have the proper load and inflation you do not need to worry about temperature variation and can expect to see operating temperatures range from +15°F to +50°F above ambient. Many TPMS have a warning temperature of between 150 and 160°F which is OK in my opinion for a warning level. It is very unlikely for you to have a tire get hot without having a loss of air precede the increase in temperature.

d. Early warning: I consider this an IMPORTANT and desirable feature
Imagine your cold pressure is 100 psi. Your low pressure warning is probably -15% or 85psi. When driving you might have a hot pressure of 120 psi. Now suppose you get a leak from a puncture or possibly a valve stem gasket leak. Would you rather get a warning when you loose 3 or 6 psi over a few minutes down from the 120 psi HOT pressure, or would you think it OK to only be warned after you loose 35 psi down from the hot pressure to the "Low Pressure Warning" level.?

In my opinion getting that "Early Warning" allows you to slow down and start looking for an exit or safe place to pull over as you monitor the air loss over then next 5 to 20 minutes you might have before you get down the the minimum pressure needed to carry the load.

Sometimes the rate of air loss can start small but increase over a few minutes as the hole in the tire gets bigger. If you only get the single warning it may already be too late to save and repair the tire.

I hope I have given you some things to consider when selecting the "Best for you" TPMS."

Hope this helps.

[smiley58]

Did you void your warranty by having someone make the hole larger? I would imagine the hole has the tire air valve in it that you made larger. Slick idea.

[Gidyupgo]

Smiley, it was waaay up the page somewhere, but I believe he said he had the hole in the hubcap/chrome wheel simulator enlarged so the screw on sensor wouldn't rub it. The hole the stem goes through was not changed, if I am remembering this right. Reading on my phone, so it woukd be scroll, scroll, scroll to go back past all of the scientific discussion to find it up there. Good question though.