A Little Confused Over G vs H Rated Tires And Load/Inflation Data -- Updated at End

[BillO]

The older coach I bought came outfitted with Dayton "G" rated tires.  After weighing the coach at the corners I find that I have to inflate these tires to the point that the coach rides pretty rough.

I'm starting to research replacement tires as the Daytons are getting toward the end of useful life.  However, the whole tire load/inflation and rating system has me a bit confused.

On some websites (Goodyear, in particular) when I look up my size (295/75R22.5) they show a load/inflation table that's identical for both G and H rated tires except that the H rated tires extend to heavier loadings.

On other sites (e.g. Bridgestone) they have different tables for G vs. H rated tires with the H rated tires requiring consistently less inflation (10-15 psi) for the same loads.

The Michelin data is equally confusing within its own lineup.  Their comparable tire -- 275/80R22.5 -- shows load data like Goddyear for some models and data like Bridgestone for other models.

I understand that there can be differences in tire construction, but also thought that there was some level of standardization in ratings and load/inflation data.  Are there no industry standards?

On a practical level, if I switch to one of the H rated tires that indicate lower required inflation will the heavier tire construction simply offset the lower pressure and result in the same ride?

[tireman9]

Lets see if i can shed some light to help clear up the confusion.

Since the load is carried by the air and not the tire it is reasonable for tires to have the same load capacity at the same inflation, no matter the Load Range. You can read more at this site.

I took a look at the Load/Inflation tables at Firestone pg 4 of 9 and find the LR-G tires are rated for 6175 Lbs @ 110 psi and LR-H 6610 Lbs @ 120 psi.

Goodyear page 15 we see the ratings 6175 @ 110 and 6610 @ 120 for the G and H Load Range.

Michelin tables for size 275/80R22.5 LR-G shows 6175 at 110 psi but LR-H shows 7160 Lbs @ 120 psi.

NOTE the different Load Range Michelin tires are also of different design so there are a number of possible reasons the 7160 Lbs is different for the other tires. This shows why it is important to check the Load/Inflation tables published by the manufacturer of your specific tires.

Industry Standards as published by Tire & Rim Association show a 295/75R22.5 and 275/70R22.5 as being rated the same at 6175 at 110 for LR-G and 6610 at 120 for LR-H. If a manufacturer makes some special provisions or design changes and tests to a different load they may choose to publish load capacity that is slightly different than you might find for a different design or from a different manufacturer.

To answer your final question, you can not simply change the Load Range but not change the inflation pressure and assume that you will have a different load

capacity. You must use the tables from your tire manufacturer for your exact tire and be sure you always check your inflation and have enough air to carry the load. You did not say what your actual loads are I can't look at the possibility of there being a choice of a tire that would allow a lower inflation but I doubt the inflation difference would be very significant.

[planocat]

"NOTE the different Load Range Michelin tires are also of different design so there are a number of possible reasons the 7160 Lbs is different for the other tires. This shows why it is important to check the Load/Inflation tables published by the manufacturer of your specific tires."

I'm with you BillO, it's still confusing to me as the Michelin tire chart I'm looking at is for the same model tire with different ratings. Guess we'll have to accept the premise that the same tire isn't really the same from load range G to H.

Thanks Tireman9 for pointing us to the right places for info.

[BillO]

Thanks for the replies.

However, I'm still confused.

Tireman9, the references that you give for Firestone and Bridgestone support the premise that a given air pressure should support a given load. In both of those cases if I take my front tires with a load of 5590 pounds (that is the maximum of the two tires) they say 100 psi min regardless of tire load rating.

Yet, when I look at the data you reference for Michelin I see a different story. That Michelin data is posted in total axle load, which in my case for the front axle would be 11,180 pounds. In their LRG series Michelin shows that I would need 100 psi min to support 11,560 pounds, but when I look at their LRH series I would only need 90 psi min to support 11,380 pounds.

The load table for the G series gives a slightly higher safety factor simply because the next step down is below the required load. However, as minimum inflations both G and H ratings have an adequate safety factor in my mind.

I'm not sure what "significant" is to you, but the 10 psi difference is significant to me and I suspect would result in a smoother ride --- If I can believe the data table.

Planocat.

I can easily understand that tires of different construction could have an overall higher load rating at a higher pressure. What I'm having the most trouble with is that the tires would have differing load capacities at the same pressure as Michelin's data implies.

[tireman9]

BillO

First off try to separate out the Axle Load info and calculate the individual tire load. I have no Idea why Michelin is different. Sometimes I think they do things different just to be different.

Second. Take a look at the actual tire designs you are considering. Michelin lists different designs with different tread patterns and tread depths.

Remembering that in general thicker rubber runs hotter than thin. Hotter is more likely to fail than cooler. These design features come into play when passing a given test.

Now it might be possible to make a table with many features and dimensions of the difference between the different Mi designs but that's a lot of work and you still might be overlooking some special construction feature.

The other item is you are really looking at 10 psi difference to gain 90# load capacity per tire. I would agree that 10 is significant as this is 10% but do not think 90# is significant as it is closer to 2%.

I am inclined to believe that Michelin gave the higher load rating for some marketing reason to meet some truck manufacturer specific need for the extra 180# on an axle.

Now I am also not sure if you could actually feel a 10 psi difference in a blind over the road evaluation and even if you can it would not be something that couldn't be achieved with a bit of extra cushion on the driver seat.

A quick review of a tire that might be good for RV application is the MI XZA3. This design has a G & H with the G rated at 6175# @ 110 and the H at 7160 @ 120 psi.

I cannot explain the difference in the numbers. Possible error in the Michelin web page?

[BillO]

Tireman9,

To your first point, I actually started with individual tire loads. I simply doubled the load on the most heavily loaded steer tire to match the Michelin table.

Second, I do understand that Michelin (and others) might have specific designs with unusual ratings. However, the G vs H thing runs throughout much of their tire line. In the table that I took the H pressure/load numbers from the heading is actually,

275/80R22.5 LRH XDE^®2+, XZA3^®, XZA3^®+ EVERTREAD ™, XZE^® ,

implying that the data apply to all those models (they have a similar table for all the G ratings).

"The other item is you are really looking at 10 psi difference to gain 90# load capacity per tire. I would agree that 10 is significant as this is 10% but do not think 90# is significant as it is closer to 2%."

I think that you missed my point here. I went to the G and H tables and found the min inflation to carry my load for each tire rating just as if I had these tires on my coach. It's not a case of 10 psi difference to gain 90# per tire. Those are loads from differently rated tires. The actual differential within one rating is considerably higher. For the G rated tire 90 psi will support 10,740# (which was below my load, as was their data at 95psi) while 100 psi supports 11,560#. For the H rated tire 90 psi supports 11,380# (which exceeds my load) and 100 psi supports 12,380# (way more than needed).

As I stated in my original post, the current Dayton tires give a pretty harsh ride when inflated to the load/inflation data (plus 5%) and I'm looking for anything that will smooth that out. Unlike a truck, my coach has a lot of things in it, beyond the driver, that suffer some from that harshness. Some on this forum have stated that simply switching from a truck-oriented tire, like Toyo, to Michelin provided a smoother ride. I can understand that in different designs and looking to take it to the next step.

Finally, it is considered common wisdom that most tire failures in the RV world are due to underinflation and that we should all follow the tire manufacturer's data. I can't imagine that it is a simple web page error because the same G vs H loading tables are all over Michelin's websites in different presentations, as well as on Bridgestone's site (as a footnote, I incorrectly typed Bridgestone when I menat Goodyear in my previous post).

Bottom line is that I'm still as confused as previously.

[tireman9]

OK got the info and I understand it. Now lets see if I can translate Tire Geek speak to English.

1. The load and inflation information on the Michelin web pages for the 275/80R22.5 LR-G and LR-H are correct.

2. The rated load for these two tires is different, even at the same inflation.

3. The reason is that the LR-G was designed to US Tire & Rim Association "TRA" standards and the LR-H was designed to similar but not identical European Tyre and Rim Technical Organization "ETRTO".

4. TRA calculations and tables were calculated in "inch" units while the ETRTO and other similar organizations like The Japan Automobile Tyre manufacturers Association "JATMA" have always been metric based.

Now introduce the fact that you take a tire originally intended for the European market and try to match it to the tire developed for the US market and convert the units then do the rounding such as the 123 psi for the max of the European LR-H etc etc and you end up with confused customers.

So bottom line.

Use the information for dimensions, load, and inflation for a specific tire as published by the manufactuer of the tire you are considering.

You can still consult other sources but you need to remember that there may be slight variations.

Just FYI here are just some of the source books that tire engineers need to consult and follow during the design process.

[BillO]

Tireman9,

Thanks for researching the issue for us. I think that the fact that these tires were developed to different standards goes a ways toward answering the question.

"Now introduce the fact that you take a tire originally intended for the European market and try to match it to the tire developed for the US market and convert the units then do the rounding such as the 123 psi for the max of the European LR-H etc etc and you end up with confused customers." (emphasis added).

That statement is sure correct ... and that's from someone with advanced engineering training!

Now, the million (perhaps thousands) dollar question for me. If the H tires are a more substantial tire (my reading of the implication that they can carry more load at a given pressure, as well as go to higher overall pressure/load) are they likely to give a harsher ride than a corresponding G rated tire inflated 10 psi more? Can that question even be answered without actually installing and riding on the tires?

The second question I still have to resolve is the distinction of regional versus long-haul tire characterization. I was originally looking at the Michelin XZE tire which is available only in H rating and is billed as Regional haul tire. The regional haul description seemed to fit my general RV driving -- a few hundred miles per day and then a number of tight curves with back and forth to get into a campground slot. I also looked at the XZA3 that you suggested earlier. This comes in both G and H as you noted and Michelin bills this as a Long-Haul tire.

Is a regional haul tire (made to endure more scrubbing, etc.) likely to have a stiffer sidewall that would ride harsher than a long haul tire? Conversely, is a long-haul tire likely to suffer more from the typical daily maneuvering of RV life?

I did see that on their RV tire site, Michelin lists the XRV tire as "long-haul" type.

I also like the 7 year/700,000 mile casing warranty on the XZA3. Not that I'll ever reach the mileage, but the duration is appealing.

Thanks again.

Bill

[tireman9]

Bill. Sorry to say there is no good way to predict the ride difference, if any when you are not changing inflation pressure.

I did significant NVH (Noise Vibration Handling) vehicle evaluations and you would be surprised at how different vehicles respond to similar tire changes. Never did a Class-A NVH test though.

If Mich lists both Regional and Long Haul on their RV tire page. I would select one from that page if you have decided to go with that brand. If all else was equal you will probably get better fuel economy with shallower tread if that makes a difference.

Good Luck and let us know what you learn after you get the new tires.

[BillO]

Thanks for clearng up the G versus H mystery for me. I guess I'll just have to make a decision and give one of the Michelin tires It's pretty hard to beat them with the new FMCA agreement.

Regards,

Bill

[rcgoss]

BillO

Have been reading these posts with some interest and have a couple of comments.

Not that he needs any reinforcement, but I'd second tireman9's suggestions/recommendations. However, I did not find any reference to specifically how much weight you have bearing on each tire on your motorhome, the maximum psi rating of the rims, or how much maximum axle loading is permitted. If you weigh the individual axles with both tire ends on the scale at a truck stop you do not know how much actual weight is being carried by each tire on the axle and that is extremely important to determine before you start going for a minimum acceptable tire pressure. Many motorhomes come stock with significant weight bias to one side or the other and then the way you load it can compound the problem. Only after you weigh your coach with independent wheel scales, should you start talking about reducing tire pressures. The weight bias on our coach is about 600 pounds more on the right front than the left front. It's significantly less on the rear axle. (Manufacturer said that was about normal and within legal limits). Thus, both front tires need to be aired up to the same pressure required for the heaviest loaded tire. On our coach that works out to right around 105 psi (minimum). I normally carry 115 psi in the in cooler temperatures and closer to 120 psi in the fronts when temperatures will be in the 80s and above. Why? I like to have a bit of tire loading cushion, especially should a tire develop a slow leak due to a road hazard or I have to drive a long distance on a crowned road with a left crosswind in the summer (seems to happen a lot here in south Texas). Bottom line, the psi margin is a personal preference. The pressures are well within the tire ratings, as well as the rim ratings for our motorhome.

It's been my experience that "tire safety" has nothing whatsoever to do with anyone's perception of a comfortable ride. After seeing results of blown tires, (other peoples, not mine) I've come to the conclusion that if riding on a cloud is what a person is looking for, a motorhome might not the best choice of travel. My most comfortable ride is now one that ends up with us arriving where we were headed with no tire issues. The roads in this country, especially the interstates, are absolutely awful in some areas and you just can't let enough air out of the tires to fix that.

That being said, I did find that when I took off my 8 year old Goodyears (Load Range H) and replaced them with Michelins (Load Range H), the handling improved dramatically as did the ride comfort even with near 120 psi in the front tires.

About Michelin tire charts...be careful which one you are looking at. I'm not sure the charts are still current but when I bought my tires I found that they had two. One for commercial vehicles, including commercial buses, and one for RVs. The same tires and sizes are listed but tire loadings at various tire pressures are different in many cases (...I suppose because as a group we RVers tend to overload our vehicles and don't tend to visually inspect our tires or check tire pressures on a regular basis and then we often go and park them in the same spot for 6 months at a time, then crank'em up and head out without checking the tire pressures. (I've seen that done on more than one occasion.)

As far as I know there is no reason to purchase an H rated tire if a G rated tire is specified by your motorhome/chassis manufacturer. While the H rated tire can carry more weight at its upper limit there may be no difference in air pressure to carry less weight than with the G, almost certainly not enough to make any ride difference. Thing is, it is the amount of tire flexing that causes the temperature to build up in a tire. Lower the air pressure and the more it flexes with a given load factor and the hotter it gets. Since the tire is composed of many different pieces/layers of rubber that were just vulcanized together (a process that bonds the various pieces and layers together with, among other things, heat). When a tire gets hot enough things can start to unravel. The harder a tire is made to work the easier it is to cause it to come apart.

Hey Tireman9, if I stated any of this incorrectly, please don't hesitate to offer corrections.

Keep the shiny side up...

[BillO]

BillO

Have been reading these posts with some interest and have a couple of comments.

Not that he needs any reinforcement, but I'd second tireman9's suggestions/recommendations. However, I did not find any reference to specifically how much weight you have bearing on each tire on your motorhome, the maximum psi rating of the rims, or how much maximum axle loading is permitted. If you weigh the individual axles with both tire ends on the scale at a truck stop you do not know how much actual weight is being carried by each tire on the axle and that is extremely important to determine before you start going for a minimum acceptable tire pressure.

I started this topic by pointing out that I had weighed the coach at the corners and further elaborated on that point in a subsequent post. I used a specific example from my front axle to point out the differences in load/inflation data between G and H rated tires. In actuality, I have to run the current G rated rear tires at maximum 110 psi to carry their load and provide 5 psi safety.

Many motorhomes come stock with significant weight bias to one side or the other and then the way you load it can compound the problem. Only after you weigh your coach with independent wheel scales, should you start talking about reducing tire pressures. The weight bias on our coach is about 600 pounds more on the right front than the left front. It's significantly less on the rear axle. (Manufacturer said that was about normal and within legal limits).

After weighing my coach and making adjustments in moveable items (both cargo and regular components) several times, I have the weight differential down to less than 150 pounds side-to-side. In my third post I pointed out that I had taken the MAXIMUM individual wheel load to use as the axle load in the Michelin table referenced.

Thus, both front tires need to be aired up to the same pressure required for the heaviest loaded tire. On our coach that works out to right around 105 psi (minimum). I normally carry 115 psi in the in cooler temperatures and closer to 120 psi in the fronts when temperatures will be in the 80s and above. Why? I like to have a bit of tire loading cushion, especially should a tire develop a slow leak due to a road hazard or I have to drive a long distance on a crowned road with a left crosswind in the summer (seems to happen a lot here in south Texas). Bottom line, the psi margin is a personal preference. The pressures are well within the tire ratings, as well as the rim ratings for our motorhome.

If you substituted rear tires for front in your example it might be my case, except that with the G rated tires I max out now at 110psi. However, when I started looking into H rated tires I noticed the anomaly that with some H rated tires the required minimum psi dropped from 105 to 90 or 95psi prompting this whole inquiry.

It's been my experience that "tire safety" has nothing whatsoever to do with anyone's perception of a comfortable ride. After seeing results of blown tires, (other peoples, not mine) I've come to the conclusion that if riding on a cloud is what a person is looking for, a motorhome might not the best choice of travel. My most comfortable ride is now one that ends up with us arriving where we were headed with no tire issues. The roads in this country, especially the interstates, are absolutely awful in some areas and you just can't let enough air out of the tires to fix that.

My inquiry really had nothing to do with tire safety relating to comfortable ride nor riding on a cloud. I DO however, believe that driving over the gravel roads of the Escapees' CG in Livingston shouldn't feel like taking a dump truck to the town dump and hoped someone could shed some light on this H rated tire pressure differential.

That being said, I did find that when I took off my 8 year old Goodyears (Load Range H) and replaced them with Michelins (Load Range H), the handling improved dramatically as did the ride comfort even with near 120 psi in the front tires.

That statement is encouraging to me, as I suspect the Dayton Metros that came with my coach probably ride worse than Goodyear.

About Michelin tire charts...be careful which one you are looking at. I'm not sure the charts are still current but when I bought my tires I found that they had two. One for commercial vehicles, including commercial buses, and one for RVs. The same tires and sizes are listed but tire loadings at various tire pressures are different in many cases (...I suppose because as a group we RVers tend to overload our vehicles and don't tend to visually inspect our tires or check tire pressures on a regular basis and then we often go and park them in the same spot for 6 months at a time, then crank'em up and head out without checking the tire pressures. (I've seen that done on more than one occasion.)

Although we've picked on Michelin in this thread, the G vs H anomaly isn't limited to them. Bridgestone shows the same thing in some of their tire line.

As far as I know there is no reason to purchase an H rated tire if a G rated tire is specified by your motorhome/chassis manufacturer.

My coach was made in 1994. Back then they listed G rated tires and considerably lower inflation pressures --- until I looked at the footnote of 55mph ratings.

While the H rated tire can carry more weight at its upper limit there may be no difference in air pressure to carry less weight than with the G, almost certainly not enough to make any ride difference.

That is exactly the anomaly that prompted this topic in the first place. SOME H rated tires have load/inflation data showing 10-15% less inflation for the same load. I addressed this earlier.

Thing is, it is the amount of tire flexing that causes the temperature to build up in a tire. Lower the air pressure and the more it flexes with a given load factor and the hotter it gets. Since the tire is composed of many different pieces/layers of rubber that were just vulcanized together (a process that bonds the various pieces and layers together with, among other things, heat). When a tire gets hot enough things can start to unravel. The harder a tire is made to work the easier it is to cause it to come apart.

These points are all valid within a particular load range of a tire. However, I'm still not convinced that the same holds true when comparing between two tires with different load ranges and load/inflation characteristics. If Michelin says their H rated XZE tire (or Bridgestone with their R280 H rated) will support 5600 pounds with 90 psi versus 100psi for a G rated tire of the same brand, then something else is going on. Seems to me that if there were a heat issue in the H rated tires both manufacturers would have footnotes to that effect.

Hey Tireman9, if I stated any of this incorrectly, please don't hesitate to offer corrections.

Keep the shiny side up...

Cheers,

Bill

[BillO]

After carefully considering the info here, as well as talking with a couple tire dealers and a Michelin tech rep I finally went with the Michelin XZA3+ tires in the H (16 ply) rating.

These tires allowed me to drop tire pressure 10 psi both front and rear while still being ~10 psi above minimum for the tire load (which is actually a bit more than safety factor than the Michelin rep suggested)

Whether its the tires, the inflation pressure or both the change in ride is pronounced. The gravel roads at my common campground no longer feel so much like an old fashioned washboard and the road/bridge gaps feel more like a bump and less like driving over a tank trap.

I'm pretty happy with the immediate result, but time will tell about durability, etc.

[andyshane]

I've enjoyed reading the thread, take an interest in tires. 'Will tell you what I've been doing, hope you can point me to something written by either the manufacturers of the Natl Hwy Tfc Safety Admin about adding a safety margin. 'Never heard that term before, want to learn more about it.

First, someone was talking about Michelin data pertaining to total axle weight; I was prompted to dig out my guide and re-read the introduction from the tire manufacturer.

For RV use only, Michelin displays tire loads per axle end in the

load and inflation tables, as we recommend weighing each axle

end

separately and using the heaviest end weight to determine

the axle's cold inflation tire pressure.

I highlighted the operative term that caught my eye.

If my math is correct, that gives you a margin of a total front axle weight up to 11,380 lbs on 90 psi. True, some of the company's tire charts refer to total axle weight; but, my RV table deals with axle-end.

After re-reading my Michelin stuff and the NHTSA guidelines, I keep coming up with the inflation table values as "recommended" rather than "minimum," and would like to hear if I've been under-inflating mine. All my crosschecks suggest that inflating to the recommended value for the rounded-upward heaviest axle-end weight is optimum for the tire itself: I've been running 85 psi in my 275/70R22.5 LRJ XZE2 Energy model with 7,000 miles of decent handling, perfect tread wear distribution and a peak running temp (IR scan, not stem temp) of 120F.

Any additional information is greatly appreciated. Super thread!

[BillO]

Andy,

I cannot give you a definitive answer on your questions, but will give it a try.

First, the whole business of total axle weight versus axle end weight came about from the initial responses and references. Michelin puts out two different sets of load/inflation tables -- one for truckers who typical roll over Cat scales at truck stops and get total axle weight and a second for RVers that SHOULD be getting axle end weights because of the potential for considerable differences due to unequal load balance.

If you read my first entry in detail, you'll see that I started with load at the axle ends. However, an early respondent referenced the truckers' load/inflation table so I converted to total axle weight simply to make my point. I did use, and am still using, the axle end loads for my own calculations.

Second, the whole business of a tire pressure safety factor doesn't come from anything to do with the tires themselves, but rather the nature of RVing. A truck will go over a scale once, settle the load into a stable pattern which is then pretty much constant until delivery. In contrast, we RVers tend to measure the axle end loads once (or maybe if you're really diligent once/year) and then go on our way. Part of that "on our way" likely includes shopping trips, souvenir collecting, etc., as well as maybe tanking up more water than normal for a convention or the like. Those actions end up adding to that initial spot weight. The safety factor is more a safety for our behavior than because the tire charts are wrong.

Perhaps you are more careful in what you do with, or bring into, your motor home in terms of weight. I'm still learning after only 3 years of fulltiming and adding/subtracting things as I go so the safety margin is worthwhile for me.

[andyshane]

Andy,

...A truck will go over a scale once, settle the load into a stable pattern which is then pretty much constant until delivery. In contrast, we RVers tend to measure the axle end loads once (or maybe if you're really diligent once/year) and then go on our way. Part of that "on our way" likely includes shopping trips, souvenir collecting, etc., as well as maybe tanking up more water than normal for a convention or the like. Those actions end up adding to that initial spot weight. The safety factor is more a safety for our behavior than because the tire charts are wrong.

Perhaps you are more careful in what you do with, or bring into, your motor home in terms of weight. I'm still learning after only 3 years of fulltiming and adding/subtracting things as I go so the safety margin is worthwhile for me.

I too am learning, eager to come up with good answers.

The tech team at Michelin got back to us with the following quote (I highlighted "correct"):

The amount of air pressure required in each tire on an RV depends on the weight of the fully loaded vehicle. Therefore, the RV has to be weighed loaded by individual wheel position. Correct procedure on weighing the RV can be found in our RV Tire Guide under "How To Weigh The Recreational Vehicle". Once the actual corner loads are known, the

correct

air pressures can be determined. Use the RV load and inflation table (

http://www.michelinrvtires.

com/michelinrv/toolbox/

reference-material.jsp

) to establish the air pressure for the heaviest side of the RV. Match the opposite tire(s) across the axle with the same pressure.

It is acceptable to add a small amount of additional pressure as a safety margin.

Salient to this, is that users can define "margin" first, eg outright extra psi or the difference between their axle-end weight and that allowed in their chosen table block; then, they can decide what is appropriate to their pressure-checking and loading habits.

In my own case, given that I manually check my tires each trip to within 2 psi of optimum, and have virtually no load variance, that my tire wear is perfect and there exists a few hundred pounds per axle-end surplus until the next higher value is called for, I'll stick with the table. For the average user, however, I think the technique of going 5 psi over the table value is probably good insurance.

Special thanks to Michelin HQ for weighing in on this one. Given the hundreds of user reports floating around out there in various forums, it is obvious that Michelin is indeed the current best choice, for RV owners.

[dickandlois]

This thread has been an interesting read !

With the tire rating G and H. OK ! I get that part.

Tire pressure to load. I get that also.

Now, when it comes to ride comfort to me the comfort that one experiences comes from the sidewall flex that each tires designed to handle in the sidewall construction.

This sidewall flexing generates heat. Heat is also retained in the tread area and depends on the tread mass and road temperatures.

So if one under inflates the tires more sidewall motion on each rotation equals more heat, and I have not read any information regarding this in a chart offering a temperature to load and inflation relationship.

Has anyone found this kind of information or have some data that one can use to find what I call the sweet spot for the tires regardless of manufacture ? No two sidewalls are designed the same regarding material and type of belting.

Rich.