Tire inflation vs altitude vs load distribution

[P & T]

Originally Posted by jadatis

Also the infuence of humidity I did research.
In the cold pressure influence of that is marginal.
Will make a list for that to, but for now, 100% humidity, the partial pressure of water is related to the temperature.
Boiling point of water 212 degrF, 100% humidity is 14.7 psi, so at average ambiënt pressure it can go on evaporating.
But in a tire with 110psi if enaugh liquid water still partial pressure of water as gas is 14.7 psi.
At 70degrF PP H2O 0.33psi.
So that lower pressure wich goes back must have another reason, mayby a slow reacting tmps sensor.

Thanks for the feedback. I figured humidity could be negligible and that's why I thought bleeding some air out (when cold) and then bringing all of the tires up to 110psi would offer my OCD mind some peace.

I paid good money for TPMS sensors to let me see what is going on. When I see the air pressure going down then up, (on one tire only) it makes me curious.

[P & T]

Originally Posted by travelin texans

I'm thinking after all these years I need to go back to school & take a 6 week course in "Tire Inflations 101"!! Never realized squirting air into a tire to its recommended pressure was so technical.
Does it matter which knee I kneel on on either side of the rv? I Normally check with gauge, lay it down, using the same hand to hold the air hose, squirt as needed, then use the gauge in that same hand again, repeat at each tire.
SORRY! For that smart a## comment, couldn't help myself!! But that's how these tire discussions seem to go!

Left knee, always.

[P & T]

Originally Posted by Tireman9

1 Stop messing with your tires every day. You are not gaining anything but are potennally damaging the valve core so it might stick and leak,


2 Your standard set inflation can be calculated from your truck scale weight readings and the load inflation tables as long as the inflation needed to carry the measured load is at least 10% below your set pressure.


3. You do not need to adjust for altitude. I covered this in my blog and at most it's only worth a couple PSI.


4. DO NOT BLEED air out of a hot tire. Only set the tires when they are not warmed up from being in the Sun or from driving.


5. You are way overthinking inflation. Just have 10% "cushion" of inflation above the number from the tables and set when tires are not in Sun and are not warm from driving. DO NOT WORRY about Sun side vs Shade side numbers while driving.


6 ONLY worry about being lower than the number in the Load/Inflation table. You can see +20 to +25% increase in hot pressure over cold pressure and all is still OK.

Thanks. I look at truck drivers all the time and wonder how they feel so confident (or are they just stupid) pushing the limits...speeding, zig zagging, short stopping distances, etc. I do take the towing as a responsibility to myself, passengers and others on the road.

There is another component here that has to do with "China bombs" and poor quality of builds from the manufacturers. As we were on the road and I saw simple things fail due to poor workmanship, it makes me want to improve every facet of the rig while driving at 55mph plus. I like to sleep well.

[P & T]

Originally Posted by Tireman9

1 Stop messing with your tires every day. You are not gaining anything but are potennally damaging the valve core so it might stick and leak,


2 Your standard set inflation can be calculated from your truck scale weight readings and the load inflation tables as long as the inflation needed to carry the measured load is at least 10% below your set pressure.


3. You do not need to adjust for altitude. I covered this in my blog and at most it's only worth a couple PSI.


4. DO NOT BLEED air out of a hot tire. Only set the tires when they are not warmed up from being in the Sun or from driving.


5. You are way overthinking inflation. Just have 10% "cushion" of inflation above the number from the tables and set when tires are not in Sun and are not warm from driving. DO NOT WORRY about Sun side vs Shade side numbers while driving.


6 ONLY worry about being lower than the number in the Load/Inflation table. You can see +20 to +25% increase in hot pressure over cold pressure and all is still OK.

I read you blog post but is the load/inflation table universal or tire specific? The link only took me to one part of the thread so I'll have to dig if it's there. Thanks in advance!

[flybouy]

Originally Posted by P & T

Thanks for the feedback. I figured humidity could be negligible and that's why I thought bleeding some air out (when cold) and then bringing all of the tires up to 110psi would offer my OCD mind some peace.

I paid good money for TPMS sensors to let me see what is going on. When I see the air pressure going down then up, (on one tire only) it makes me curious.

Not to retrigger your OCD but if you think about is logically, have you ever seen a tire installer install a tire and pull a vacuum on it before inflating? They use "shop air" to inflate tires. Most tire shops use an in-line water separator on their hoses and not expensive air dryers like paint shops use.

Air up tires, drive, monitor your TPMS and relax. Life is too short to obsess over this.

[Tireman9]

Originally Posted by LeeSpice

I also have the Salin Tires with a max of 110lbs (think they're the same model as yours) I've been worried because they're Chinese tires and I had a chinese tire explode on me about 3 years ago. On a smaller trailer, they were trailer Kings. I read the Reviews on the Salin and they seem much more heavy duty, so I've left them on (for now). On tire pressures I was also religiously putting them at 110lb cold. But in May I was traveling in San Antonio and spoke to a tire shop and the friendly guy said you don't need 110lbs unless you're running max load on the tire, which I think is about 4K pounds. I found a table for this. Actually you should be inflating the tire based on the load on the tire. I calculated the weight and backed off to 95lbs, based on the table. The guy at the shop said it's better not to overinflate the tire since the trailer rides better and the tire can deflect in response to road hazards (as opposed to failing).

How did you "calculate" the load? Ideally you would have a scale reading. Sorry but as an actual tire design and forensic engineer your "tire guy" is mistaken. Lower inflation means more deflection which means more heat being generated in the tire structure. This heat can be the cause of shorter tire life.

[Tireman9]

Originally Posted by travelin texans

I'm thinking after all these years I need to go back to school & take a 6 week course in "Tire Inflations 101"!! Never realized squirting air into a tire to its recommended pressure was so technical.
Does it matter which knee I kneel on on either side of the rv? I Normally check with gauge, lay it down, using the same hand to hold the air hose, squirt as needed, then use the gauge in that same hand again, repeat at each tire.
SORRY! For that smart a## comment, couldn't help myself!! But that's how these tire discussions seem to go!

I believe that I am the only actual tire design engineer on this thread and can tell you that there is an amazing amount of incorrect information on tires and inflation out there.


But tamping out the fires of mis-information means I will never be out of a job.

[wiredgeorge]

Originally Posted by Tireman9

Yes I suggest people ignore that post. It's as useful as "Mental Masturbation"

Marshall? He fired across your bow! This should be great.... don't disappoint and come up with a good response for your fans!

I am the only certified non-tire engineer and wise guy on this thread and I can truly say it has gone downhill rapidly and doesn't seem to have hit bottom yet. Marshall! Honestly, you just air your LRE tires to 80PSI and use a TPMS? How have you survived all these years? Do you wife and friends know?

[flybouy]

Originally Posted by wiredgeorge

Marshall? He fired across your bow! This should be great.... don't disappoint and come up with a good response for your fans!

I am the only certified non-tire engineer and wise guy on this thread and I can truly say it has gone downhill rapidly and doesn't seem to have hit bottom yet. Marshall! Honestly, you just air your LRE tires to 80PSI and use a TPMS? How have you survived all these years? Do you wife and friends know?

I think he was referencing the post that I made the comment about. I often do stupid stuff so my default is the KISS (keep is simple stupid) methodology. I do however feel jeoulose that I don't have the time to dwell on the minutia of these type of threads.

[sourdough]

Originally Posted by Tireman9

I believe that I am the only actual tire design engineer on this thread and can tell you that there is an amazing amount of incorrect information on tires and inflation out there.


But tamping out the fires of mis-information means I will never be out of a job.

Well....some put credence in titles others in actual experience. I know a guy(s) that has I don't know how many "degrees", "titles" and "doctorates". He loves to tout his "knowledge" by quoting his "degrees". Now can he change shocks, install a lift, tell a good tire from a bad one etc.? Nope, that would be me or someone else. Does he have any sense? He was behind the door when that was passed out. Of course when I called him on it years ago he told me he had written all kinds of papers that were "studied" and people found value in....I shook my head and told him that was a shame.

All to say a title has value to the holder of that title - I learned long ago that I looked for other qualities in addition to that before I hired someone. Maybe to a potential employer but the one that will decide what is misinformation or not will be me so you don't have to waste your time trying to tamp out any fires for me.

[P & T]

Originally Posted by flybouy

Not to retrigger your OCD but if you think about is logically, have you ever seen a tire installer install a tire and pull a vacuum on it before inflating? They use "shop air" to inflate tires. Most tire shops use an in-line water separator on their hoses and not expensive air dryers like paint shops use.

Air up tires, drive, monitor your TPMS and relax. Life is too short to obsess over this.

Damn, retriggered OCD.

I get not pulling it into a vacuum but then there are the "nitrogen" arguments that I've heard over the years. I never gave much thought to a refrigerated air dryer added to my shop compressor, but hmmm

[flybouy]

Originally Posted by P & T

Damn, retriggered OCD.

I get not pulling it into a vacuum but then there are the "nitrogen" arguments that I've heard over the years. I never gave much thought to a refrigerated air dryer added to my shop compressor, but hmmm

Sorry about the trigger. I don't have a "shop" just a garage full of tools and junk. I have 2 methods of controlling moisture on my compressor. First is a simple air/water separator that requires manually drying periodically. I also added a solenoid automatic blow off valve on the compressor tank. When I shut the compressor down it automatically dumps the low point drain on the tank. I don't do any fine paint work so it keeps the air dry enough for my use. I also have an automatic oiler for the branch that I connect the airtools on. Over the years I find myself using fewer air tools and more cordless tools. These days they are just as effective and less cumberson IMO.

[flybouy]

Originally Posted by Tireman9

I believe that I am the only actual tire design engineer on this thread and can tell you that there is an amazing amount of incorrect information on tires and inflation out there.


But tamping out the fires of mis-information means I will never be out of a job.

I didn't know the forum had hired an "actual tire design engineer". Why wasn't I told about this?

[wiredgeorge]

Originally Posted by flybouy

I didn't know the forum had hired an "actual tire design engineer". Why wasn't I told about this?

I had one of our esteemed experts jump on me when I suggested the use of RV toilet paper to a new owner. He cited his many years of overarching RV experience to tell me that RV toilet paper wasn't needed; just septic safe. When someone feels the need to cite their vast expertise and experience I generally consider that person a... well to be nice... I won't say.

Many folks on this site have vast and comprehensive experience in many areas I do not but telling folks how smart you are is like going into a bar and telling everyone in the bar you are the bad man who can whup anyone in the joint. There is always someone waiting to hear that type thing.

[flybouy]

Originally Posted by wiredgeorge

I had one of our esteemed experts jump on me when I suggested the use of RV toilet paper to a new owner. He cited his many years of overarching RV experience to tell me that RV toilet paper wasn't needed; just septic safe. When someone feels the need to cite their vast expertise and experience I generally consider that person a... well to be nice... I won't say.

Many folks on this site have vast and comprehensive experience in many areas I do not but telling folks how smart you are is like going into a bar and telling everyone in the bar you are the bad man who can whup anyone in the joint. There is always someone waiting to hear that type thing.

There are many narcissistic people in the world (look at just about any politician) and self proclaimed "experts" that are prevalent en masse on social media. It's just a part of life and social media enables it by having for all practical purposes one way conversations. Some just feel the need to be "the authoritative voice" in EVERY post and don't realize that most folks see thru the BS.

I like your bar analogy but I can tell you from personal experience that there's another side to that coin. When I was young I was pretty strong and tall for the times. I cleared out a few bars in my youth and it always started the same way. Some little Walter Mitty would get drunk off his bottom and thought he was Super Man. Then he'd pick the largest guy at the bar to "prove his masculinity" that he lacked when sober. It was a lose lose situation because if I just backhanded the twerp and put him down I was the bad guy for hitting someone smaller. Take the insults and move on and I was a coward. It took me a couple of brawls to realize it wasn't worth it and just not frequent those bars.

Social media is very similar. There's always someone that wants' to challenge everyone and hiding behind a keyboard gives them the courage like that alcohol gives a drunk. It's all a matter of degrees and how far someone goes with their behavior. Just my opinion.

[Tireman9]

Originally Posted by sourdough

Well....some put credence in titles others in actual experience. I know a guy(s) that has I don't know how many "degrees", "titles" and "doctorates". He loves to tout his "knowledge" by quoting his "degrees". Now can he change shocks, install a lift, tell a good tire from a bad one etc.? Nope, that would be me or someone else. Does he have any sense? He was behind the door when that was passed out. Of course when I called him on it years ago he told me he had written all kinds of papers that were "studied" and people found value in....I shook my head and told him that was a shame.

All to say a title has value to the holder of that title - I learned long ago that I looked for other qualities in addition to that before I hired someone. Maybe to a potential employer but the one that will decide what is misinformation or not will be me so you don't have to waste your time trying to tamp out any fires for me.

I don't recall mentioning any degrees. But if it helps I have over 40 years experience is designing and specifying the components and compounds to be used in a variety of tires including Truck Tires, Indy race tires, Passenger and Light Truck tires. I am a Court Recognized "Expert" in Failed Tire Forensics. I have presented and taught tire inspection to many other Tire Engineers and to the Engineers at DOT. I have worked with Ford, GM, Chrysler, Honda, Toyota, Nissan, MB, and Mazda to answer and resolve a variety of tire related issues. I discovered and have published articles on the Interply Shear forces that are unique to RV Trailer applications. Maybe you don't consider any of the above as having value when it comes to tire performance or durability. As far as on-hand experience I owned and drove a few race cars at tracks like Riverside, Daytona, Mid-Ohio, Mosport & Road Atlanta. Our team won 3 consecutive 24 hour races at the "Longest day" of Nelson so I do know how to "change a shock" or do a brake job in under 4 minutes.
So after reviewing my 500+ posts on my RVTireSafety blog what is your question and where did I give incorrect advice? If I made a mistake I would like to know so I can correct it.

[CWtheMan]

Originally Posted by Tireman9

So after reviewing my 500+ posts on my RVTireSafety blog what is your question and where did I give incorrect advice? If I made a mistake I would like to know so I can correct it.

You gave incorrect/incomplete information in this thread about inflation to the load carried.

The USTMA gives an example of inflation for the load carried for automotive RVs. By applying that without their caveat ("However, Never use inflation pressures below the vehicle manufacturers recommendations")you disagrerd with your own industry's standards (USTMA).

Wouldn't you be using a double standard by not following your industries standards?

[sourdough]

Originally Posted by Tireman9

I don't recall mentioning any degrees. But if it helps I have over 40 years experience is designing and specifying the components and compounds to be used in a variety of tires including Truck Tires, Indy race tires, Passenger and Light Truck tires. I am a Court Recognized "Expert" in Failed Tire Forensics. I have presented and taught tire inspection to many other Tire Engineers and to the Engineers at DOT. I have worked with Ford, GM, Chrysler, Honda, Toyota, Nissan, MB, and Mazda to answer and resolve a variety of tire related issues. I discovered and have published articles on the Interply Shear forces that are unique to RV Trailer applications. Maybe you don't consider any of the above as having value when it comes to tire performance or durability. As far as on-hand experience I owned and drove a few race cars at tracks like Riverside, Daytona, Mid-Ohio, Mosport & Road Atlanta. Our team won 3 consecutive 24 hour races at the "Longest day" of Nelson so I do know how to "change a shock" or do a brake job in under 4 minutes.
So after reviewing my 500+ posts on my RVTireSafety blog what is your question and where did I give incorrect advice? If I made a mistake I would like to know so I can correct it.

In post 47 you stated you believed you were the only "actual" tire design engineer on the thread. An actual engineer will have a degree of some kind from some place. You have stated that countless times throuhout many threads so you obviously place it in high regard.

I'm not going back to re-read your previous posts as I'm sure I've read them in the past. I'm sure there will be some errors but they probably didn't warrant a rebuttal. As for questions, I have none you can provide answers to.

[Tireman9]

Done with this thread. You can ask your tire questions of others.

[P & T]

So I finally found this chart but it only shows single or dual. Is this normal that triple axle would not be shown? Either way it's 110psi and I guess if I keep a 10% cushion (actual load vs. rating), then I'm good, I think.