Micro-minnie tire upgrade

[jadatis]

Dont maniacally change pressure every trip.
Checking is OK, but yust let it change with temperature in tire. Even if goes cold above the reference-pressure belonging to the loadrange.

And certainly dont blead air from a warm tire. Not because you burn your fingers, but the tire needs the lesser deflection that goes with the higher pressure, to give lesser heatproduction.

If you determined a pressure with a comfortable reserve, only check if in line with the temperature change, if so do nothing.

For that I made a handy list, so you can roughly calculate it by head, even when driving.

Use it like this.
Look up the cold pressure you filled for the axle.
Then read behind the degr. F / PSI.
Remember that or write it down.
My list assumes cold filled ( when temp in and out the tire is the same) at 70 degr. F, but if you calculate it going from 60 degr, it wont give dramatic differences.

70degrF./degrF/psi
26 psi/ 13 F/psi
27 psi/ 12,5F/psi
28 psi/ 12,5F/psi
29 psi/ 12 F/psi
30 psi/ 12 F/psi
31 psi/ 11,5F/psi
32 psi/ 11,5F/psi
33 psi/ 11 F/psi
34 psi/ 11 F/psi
35 psi/ 10,5F/psi
36 psi/ 10,5F/psi
37 psi/ 10 F/psi
39 psi/ 10 F/ps
40 psi/ 9,5 F/psi
42 psi/ 9,5 F/psi
43 psi/ 9 F/psi
45 psi/ 9 F/psi
46 psi/ 8,5 F/psi
49 psi/ 8,5 F/psi
50 psi/ 8 F/psi
53 psi/ 8 F/psi
54 psi/ 7,5 F/psi
58 psi/ 7,5 F/psi
59 psi/ 7 F/psi
63 psi/ 7 F/psi
64 psi/ 6,5 F/psi
70 psi/ 6,5 F/psi
71 psi/ 6 F/psi
77 psi/ 6 F/psi
78 psi/ 5,5 F/psi
86 psi/ 5,5 F/psi
87 psi/ 5 F/psi
96 psi/ 5 F/psi
97 psi/ 4,5 F/psi
109 psi/ 4,5 F/psi
110 psi/ 4 F/psi
126 psi/ 4 F/psi
127 psi/ 3,5 F/psi
148 psi/ 3,5 F/psi
149 psi/ 3 F/psi
177 psi/ 3 F/psi

[tinglett]

Nice!

This is good to know. I usually try to look at my tire temps ahead of a trip before the tires get hit hard by the sunlight. But sometimes I'll be scratching my head because one side of the trailer is in the shade and the other is in intense sunlight.

So if I follow, if my 65 psi tires show correct on the shade side (let's assume 70F), and let's say the sunny side shows as 96F, then I should expect the tires to be about 4 psi higher? That is, 69 psi on that side would still be "normal"?

I normally don't fret about this so long as the tires are consistent. I also figure my tires are unlikely to get additional air by accident .

[jadatis]

You show that you understand how to calculate with my list.
26 degrF temperature rising/ 6.5 degrF= 4 psi.

But in practice in your example you measure a 4 psi higher pressure, and calculate from that, that the sunny side must have 96 degr F in tire.

So on a hot morning, when stupid mother nature did not let it cool down during the night, and still 96 degrF in the shade(both sides of RV) tires need the 69 psi in your example.
If you then measure 65 psi, you must have lost some air from the tires (or whatever gascompound, like more Nitrogen)

[Tireman9]

Originally Posted by Bcborn

Tireman9 thank you for your input.
I pulled this link from your blog.

https://www.rvtiresafety.net/2019/08...ange-what.html

From reading your blog, if that guy inflated his Load Range "D" ST tires to the 50lbs as shown on the decal, you stated he would gain nothing as the 50lbs would give him (see charts below). One might add, If he wanted to try that, would he not need to know, if the given Load Range "D" ST tire would support the manufacturers stated GAWR of 7000lbs at 50psi (as did the Load range "C" originally equipped tire). Looking at the table below, for the endurance yes. If so would he not gain a smoother ride at 50lbs inflation? Would he though loose longevity?
Increasing the label recommendation 10% (55psi) or 20% (60psi) as you suggested would give him more reserve and he would still be under the Load Range "D" ST tire max of 65psi. Again would he be sacrificing longevity.

If you over inflate a tire past its required air pressure for any given load based on tire load inflation tables (in this case he is guessing as the weight every trip could be different), does the tire not tend to wear in the center as the GAWR weight may not be their to flatten out the tire to achieve even wear. Same holds true if you under inflate a tire, would you not get greater wear on the outer edges?
Winnebago the Manufacturer achieved compliance by installing the Load Range "C" tire (1760lbs load rating). Why would they install a Load Range "D" (2040 lbs load rating) on this same trailer, except for greater reserve. I get it greater reserve means increased safety (assuming the trailer gets overloaded).
Did I and many others make the right choice in replacing the OEM tire with a tire of greater load capacity (I Carlysle Radial Trail HD and other's with the Goodyear Endurance) when we never load the trailer to the maximum GAWR (3300lbs cargo)?
Thanks again Tireman9

Without covering your statements point by point:
The RV MFG by Regulation must provide tires that are capable of supporting the GAWR. There is nothing prohibiting having tires with load capacity greater than GAWR.

Depending on tire size it is possible for LR-C to provide exactly 100% of the GAWR load BUT RVIA (Gold oval sticker on the side of many RV near the door) recently changed their requirements that tires must be able to support 110% of GAWR, so the RVIA requirements are "Better" than DOT Regulation. Am I correct that Winni are RVIA Approved?

If you only need 50 psi (LR-C) to support the GAWR I see nothing wrong with a MFG providing LR-D tires and still showing 50 psi on the Certification label, assuming they meet both DOT and RVIA requirements. Nothing wrong that is other than not providing better tire life for their customers. Given the supply issues due to COVID etc a MFG may have been able to get LR-D tires but not LR-C tires so chose to provide the LR-D tires so they could sell the unit. BUT staying with 50 psi does nothing to provide a Reserve Load.

As I previously pointed out specifying an inflation greater than what is needed to support exactly 100% of GAWR is done every day on almost every car and many trucks every day. Here are a few examples.



Yes lower inflation will give smoother ride but at a cost of tire durability. One of the main reasons for better durability of tires on cars is because as a group they have a smaller percentage of tires in overload with over half of RVs that have been weighed showing a tire and or axle in overload.


Finally I do not understand why people think that running tires in overload or with almost no Reserve Load is not going to come back and bite them. None of this addresses the significant and unique shear forces placed on tires when they are in trailer service. An argument could be made that trailer tires need AT LEAST 25% Reserve load (the amount needed to offset the Interply Shear forces) with something closer to 40 or 50% being needed to allow tires to wear out befor they age out.

[Tireman9]

Originally Posted by jadatis

Dont maniacally change pressure every trip.
Checking is OK, but yust let it change with temperature in tire. Even if goes cold above the reference-pressure belonging to the loadrange.

And certainly dont blead air from a warm tire. Not because you burn your fingers, but the tire needs the lesser deflection that goes with the higher pressure, to give lesser heatproduction.

If you determined a pressure with a comfortable reserve, only check if in line with the temperature change, if so do nothing.

For that I made a handy list, so you can roughly calculate it by head, even when driving.

Use it like this.
Look up the cold pressure you filled for the axle.
Then read behind the degr. F / PSI.
Remember that or write it down.
My list assumes cold filled ( when temp in and out the tire is the same) at 70 degr. F, but if you calculate it going from 60 degr, it wont give dramatic differences.

70degrF./degrF/psi

snip
177 psi/ 3 F/psi

jadatis please stop overloading people with the extra information. You are making their life much more complex and complicated than it needs to be. If they inflate their tires to at least the needed inflation when the tires are not warmed they should be good to go. Especially if they add a 10% cushion on inflation so they don't need to chase the inflation every time the Ambient temperature changes a couple degrees. That 10% inflation margin covers them for a change in Ambient of 50F.Only in extreme cases will they need to adjust air pressure. A couple years ago I traveled from Ohio to Oregon to Banff to Glacier & Yellowstone and back to Ohio over a 7 week period. Only one time during the 7 weeks I decided to add 2 to 4 psi to my tires and at no time did my reserve inflation drop below 5%.

[tinglett]

Originally Posted by jadatis

You show that you understand how to calculate with my list.
26 degrF temperature rising/ 6.5 degrF= 4 psi.

But in practice in your example you measure a 4 psi higher pressure, and calculate from that, that the sunny side must have 96 degr F in tire.

I look at this differently because I have a TPMS that shows pressure and temperature. In theory at a glance I know that I'm good to go or need to top off with air. Usually I'm good to go. But sometimes that sunlight is heating up tires. Now I have a bit of an idea of what's expected and what is too low -- and more specifically I know I'm within 3-4 PSI which is within my operating range anyway. So I can quit worrying about it .

That's my perspective on this.

[tinglett]

Originally Posted by Tireman9

If you only need 50 psi (LR-C) to support the GAWR I see nothing wrong with a MFG providing LR-D tires and still showing 50 psi on the Certification label, assuming they meet both DOT and RVIA requirements. Nothing wrong that is other than not providing better tire life for their customers. Given the supply issues due to COVID etc a MFG may have been able to get LR-D tires but not LR-C tires so chose to provide the LR-D tires so they could sell the unit. BUT staying with 50 psi does nothing to provide a Reserve Load.

Sorry, I'm maybe feeling a little dense as there is a lot of information here. I think you are saying it over and over, but here goes the question:

Let's say my tires are very much over spec for my actual weight that I've checked at a CAT scale. Yes, technically I can run them on less air safely (per a chart) for a "smoother" ride. But I think you are saying the tires will last a lot longer if I don't do this. Instead, run them at their full rated inflation and they will run a lot longer and hopefully wear out before they age out.

Do I have this right? I don't have a problem with "hard" tires. Honestly, there's an earthquake back there either way when I'm running down the road. I can hardly imagine softer tires make that big a difference in the grand scheme of things.

[jadatis]

I dont see what I am making it complicated.
Yust making it as simple as possible.
If you understand the system, you dont do wrong things, like bleading air from a warm tire., for instance.

[jadatis]

Originally Posted by tinglett

I look at this differently because I have a TPMS that shows pressure and temperature. In theory at a glance I know that I'm good to go or need to top off with air. Usually I'm good to go. But sometimes that sunlight is heating up tires. Now I have a bit of an idea of what's expected and what is too low -- and more specifically I know I'm within 3-4 PSI which is within my operating range anyway. So I can quit worrying about it .

That's my perspective on this.

When does your TMPS begins giving psi and temperature?
Most shut down when standing, and start up when driving.
But the temperature reading of external sensors is not reliable, because gives temp at the end of the valve.
Then with my system you can check it.
Cold pressure it gives exact, because same temp at the end of valve as inside the tire.

[Tireman9]

Originally Posted by RocknRoll

Very informative thread. If I may throw in my recent experience...

One thing I do not see mentioned is how outside temperatures can affect tire pressures. Last Nov-Dec, I had a R/T excursion from upstate SC to the Keys.

Outside temperatures ranged from the mid-30's to the 90's and I found myself either adding or reducing air not only prior to every trip, but on a few occasions during mid-travel. The tires on the side of the trailer facing the sun would increase by 2-3 lbs. alone. This was worrisome as I was constantly attempting to monitor and maintain a constant psi in the tires.

The point I'm trying to make and what I've discovered is that having a margin of safety, especially in temperature extremes cannot be understated.

I still have the stock china bomb tires still on my TT and consider myself extremely fortunate that I did not suffer any negative consequences. I plan on replacing them this year with a "D" or higher rating before my next trip.

I have covered the effects of a change in Ambient temperature in great detail in my RV Tire Safety Blog with some 40 posts on Cold Inflation pressure or similar. I have also covered my reason for recommending that people run a +10% margin on inflation over the minimum needed to support the load so they do not have to worry about adjusting pressure every time the Ambient changes a few degrees.


Bottom line: Once you have learned the MINIMUM inflation to run on your RV based on actual scale measurement of the heaviest loading expected and consulting the load inflation tables you add 10% to that number. With tire pressure changing at about 2% for each change in Ambient of 10°F, that 10% margin should cover you for a drop of as much as 40 or 50 degrees.
Using the readings from my TPMS in the morning of each travel day I can monitor my pressure change and know if I need to plan on adding pressure if there has been a significant temperature drop or just keep an eye on the pressure if it has gone up. Most days I make no adjustment.


You do not need to worry about a change in pressure of + a few psi as long as you know you are still above the MINIMUM inflation and have not seen a pressure increase of 20% or more.
I would never adjust pressure during a travel day and if I am going to adjust I will only adjust once when I am done traveling for that day. Usually the next AM when the tires have cooled down to the surrounding Ambient temperature..
Remember that the inflation pressure in the tables or on your RV Certification sticker are when the tire is not warmed up from being driver or in direct sunlight for the previous 2 hours.

In my post on how I program my TPMS I cover the margins by setting the Low pressure warning level to protect the tire from ever being lower then the minimum required. My high pressure warning is set to +20 to + 25% as undamaged tires can easily tolerate that higher pressure assuming they were set correctly in the first place.

[Tireman9]

Originally Posted by tinglett

Sorry, I'm maybe feeling a little dense as there is a lot of information here. I think you are saying it over and over, but here goes the question:

Let's say my tires are very much over spec for my actual weight that I've checked at a CAT scale. Yes, technically I can run them on less air safely (per a chart) for a "smoother" ride. But I think you are saying the tires will last a lot longer if I don't do this. Instead, run them at their full rated inflation and they will run a lot longer and hopefully wear out before they age out.

Do I have this right? I don't have a problem with "hard" tires. Honestly, there's an earthquake back there either way when I'm running down the road. I can hardly imagine softer tires make that big a difference in the grand scheme of things.

Sounds like you know your actual tire loads. If you have "up-rated" your tires you could see what inflation on the new tires would deliver 30 to 35% Reserve load. That may be less that the up-rated tire sidewall number. On my Class-C I run +20 to +25% reserve load. BUT a Class-C does not have the extra forces from extra Interply Shear so trailer applications could use better reserve than what I have on my Class-C.

seen in tires in trailer application.

[Bcborn]

Originally Posted by Tireman9

Bottom line: Once you have learned the MINIMUM inflation to run on your RV based on actual scale measurement of the heaviest loading expected and consulting the load inflation tables you add 10% to that number. With tire pressure changing at about 2% for each change in Ambient of 10°F, that 10% margin should cover you for a drop of as much as 40 or 50 degrees.

I cannot seem to find a Carlyle inflation tables for their ST tires.

If I'm following this thread correctly, most owners are not upgrading the load capacity of their tire (C -> D) to carry more load, but to increase durability, safety and provide greater reserve before the tire is overloaded.

If the GAWR is below the max, lets take a Micro Minnie with a GAWR of 7000lbs.

In a perfect world, (tandem axle) each tire needs to support 1750lbs. The typical load range "C" supports 1760 at 50psi. Add an additional 10% safety factor and we are at 55psi per tire which is the max for a load range "C" tire.

Like the Load Range "C" Tire, the load range Range "D" tire is rated to support 1760lbs per tire at 50psi too, and a whopping 2040lbs per tire at 65psi, for a maximum capacity of 8160GAWR.

If an owner loaded their 7000 GAWR Minnie to 7800lbs (1950/tire) with a "D rated tire inflated to 65psi (tire max) your in range for the tire, but you have over loaded the trailer.

You load your 7000lb GAWR Mini with load range "D" tires to 8100lbs (2050 x 4) you will likely find more than a tire scattered across the highway.

Tireman9 I have never heard you say; If an owner upgrades the tire to a heavier load range and the trailer GAWR is never exceeded, it's acceptable to inflate the upgraded tire 10% over trailer decal for the trailer. But a better option due to shear forces to inflate to 25%, no greater than the max which tire is rated, this satisfies the load/inflation tables and provides a greater reserve over stock.

[Bcborn]

Originally Posted by Bcborn

I cannot seem to find a Carlyle inflation tables for their ST tires.

If I'm following this thread correctly, most owners are not upgrading the load capacity of their tire (C -> D) to carry more load, but to increase durability, safety and provide greater reserve before the tire is overloaded.

If the GAWR is below the max, lets take a Micro Minnie with a GAWR of 7000lbs.

In a perfect world, (tandem axle) each tire needs to support 1750lbs. The typical load range "C" supports 1760 at 50psi. Add an additional 10% safety factor and we are at 55psi per tire which is the max for a load range "C" tire.

Like the Load Range "C" Tire, the load range Range "D" tire is rated to support 1760lbs per tire at 50psi too, and a whopping 2040lbs per tire at 65psi, for a maximum capacity of 8160GAWR.

If an owner loaded their 7000 GAWR Minnie to 7800lbs (1950/tire) with a "D rated tire inflated to 65psi (tire max) your in range for the tire, but you have over loaded the trailer.

You load your 7000lb GAWR Mini with load range "D" tires to 8100lbs (2050 x 4) you will likely find more than a tire scattered across the highway.

Tireman9 I have never heard you say; If an owner upgrades the tire to a heavier load range and the trailer GAWR is never exceeded, it's acceptable to inflate the upgraded tire 10% over trailer decal for the trailer. But a better option due to shear forces to inflate to 25%, no greater than the max which tire is rated, this satisfies the load/inflation tables and provides a greater reserve over stock.

Should have read GVWR in all and not GAWR in my post, my bad. The GAWR was 3500/axle x 2 = 7000 GVWR

[tinglett]

What still has me a bit puzzled is whether or not I'm throwing money away by upgrading my tires. Sure, it's nice to have more margin, but is there any value to going to 70% over vs 25% over? That's what would happen if moved up to an E load tire (which would need new wheels on my rig). Sure, these numbers are at full inflation so I could run the E load tire with less PSI, but I'm not hearing that this helps longevity at all. I would get a "softer" ride, however one might measure the value of that.

It sounds like the main thing is to keep within recommended spec, and by this I mean with the recommended margin. It sounds like 25% is plenty. But, of course, I need to actually weigh the trailer to make sure I am really in this definition of "spec."

[Tireman9]

Originally Posted by Bcborn

I cannot seem to find a Carlyle inflation tables for their ST tires.

If I'm following this thread correctly, most owners are not upgrading the load capacity of their tire (C -> D) to carry more load, but to increase durability, safety and provide greater reserve before the tire is overloaded.

If the GAWR is below the max, lets take a Micro Minnie with a GAWR of 7000lbs.

In a perfect world, (tandem axle) each tire needs to support 1750lbs. The typical load range "C" supports 1760 at 50psi. Add an additional 10% safety factor and we are at 55psi per tire which is the max for a load range "C" tire.

Like the Load Range "C" Tire, the load range Range "D" tire is rated to support 1760lbs per tire at 50psi too, and a whopping 2040lbs per tire at 65psi, for a maximum capacity of 8160GAWR.

If an owner loaded their 7000 GAWR Minnie to 7800lbs (1950/tire) with a "D rated tire inflated to 65psi (tire max) your in range for the tire, but you have over loaded the trailer.

You load your 7000lb GAWR Mini with load range "D" tires to 8100lbs (2050 x 4) you will likely find more than a tire scattered across the highway.

Tireman9 I have never heard you say; If an owner upgrades the tire to a heavier load range and the trailer GAWR is never exceeded, it's acceptable to inflate the upgraded tire 10% over trailer decal for the trailer. But a better option due to shear forces to inflate to 25%, no greater than the max which tire is rated, this satisfies the load/inflation tables and provides a greater reserve over stock.

I think you will find that all ST type tires follow the published Load& Inflation tables published by The US Tire & Rim Association aka TRA. If you need more information about these standards you can sometimes find a copy on eBay or in the Engineering Library of a few colleges.


RE the max inflation for LR-C. I just checked my copy of TRA and do not find any size ST tire with LR-C at 55 psi so I am wondering and would be interested to know where you fount that information.


My comment on "up-grading" from LR-C to LR-D was not intended to suggest also increasing the actual load on the tires but to increase the inflation to provide a greater Reserve Load. Increasing the inflation on a LR-C tire will not provide greater load capacity or more Reserve Load as tires clearly state the Maximum load capacity and the inflation needed to get that max Load. There is no increase of inflation above 50 psi in a LR-C tire that will result in an increase Load capacity.

You need to remember that GVWR is not always the total of the axles GAWR. IMO it is best to leave GVWR out of discussions on tire loading.

[Tireman9]

Originally Posted by tinglett

What still has me a bit puzzled is whether or not I'm throwing money away by upgrading my tires. Sure, it's nice to have more margin, but is there any value to going to 70% over vs 25% over? That's what would happen if moved up to an E load tire (which would need new wheels on my rig). Sure, these numbers are at full inflation so I could run the E load tire with less PSI, but I'm not hearing that this helps longevity at all. I would get a "softer" ride, however one might measure the value of that.

It sounds like the main thing is to keep within recommended spec, and by this I mean with the recommended margin. It sounds like 25% is plenty. But, of course, I need to actually weigh the trailer to make sure I am really in this definition of "spec."

I am not advocating the need for 75% reserve load so replacing LR-C with LR-E or LR-F for that matter is not needed or advised.


Most vehicles on the road today i.e. cars, are running with about 35% Reserve Load while most RV trailers have a negative Reserve Load i.e. are overloaded. This is a major portion of why RV trailers have so many tire failures relative to other vehicles on the highway. I really do not understand why people think there are no negative consequences to overloading their tires. I doubt that people are overfilling the engine with oil in the expectation of better engine performance. If you weigh 350# how comfortable would you be climbing a ladder rated for 200#?


Tires have no "magic" rubber and while they can tolerate a fair amount of abuse and occasional overloading, they do have a finite life and every mile driven underinflated or overloaded is consuming a greater portion of the finite life that the miles driven at 90% or maybe even 80% of the tire max load. Remember that load is directly related to your inflation so running low on air amounts to the same damage as running overloaded.

[Bcborn]

Originally Posted by Tireman9

RE the max inflation for LR-C. I just checked my copy of TRA and do not find any size ST tire with LR-C at 55 psi so I am wondering and would be interested to know where you fount that information.

https://tirepressure.org/special-tra...rt#ST205/75R14

My comment on "up-grading" from LR-C to LR-D was not intended to suggest also increasing the actual load on the tires but to increase the inflation to provide a greater Reserve Load. Increasing the inflation on a LR-C tire will not provide greater load capacity or more Reserve Load as tires clearly state the Maximum load capacity and the inflation needed to get that max Load. There is no increase of inflation above 50 psi in a LR-C tire that will result in an increase Load capacity.

I agree you should not inflate past the max. Some dealers tell you not to inflate to the max (Not Winnebago) The reason I upgraded to a Load Range "D" tire (and assume most others) is for greater durability(a result of greater reserve, I'm learning here) To get that one must inflate the Load Range "D" to the tire max of 65psi.

You need to remember that GVWR is not always the total of the axles GAWR. IMO it is best to leave GVWR out of discussions on tire loading.

Winnebago gives three weights; (A) Cargo Carrying Capacity, (B) GVWR and (C) GAWR. I'm not sure in other cases, but for my 2017 Micro Minnie 2106FBS it just happens the GVWR (7000lbs) is twice the GAWR which is 3500lbs per axle. The Cargo carrying capacity is 3300lbs.

Manufactures I would think base the GVWR ensuring the axle/s carry that weight. If you were pulled into a scale, I assume they weigh the trailer to see if the GVWR is exceeded (not sure they weigh each axle individually as they do on most other vehicles (correct me if I'm wrong here).

As you stated trailer tires typically end up with a negative reserve (a result of an over loaded the trailer). We could talk about improper weight distribution too (will leave that for another day). Bottom line most issues are human error

My trailer loaded with gear comes in close to 5700lbs, a far cry from the maximum of 7000lbs. I'm probably not the only owner that never experiences the maximum weight capacity. Thus the question do we need to inflate to the tire maximum. As you stated it is good practice to inflate to the maximum if you do not know the exact maximum load on any given tire. Not to mention increased reserve is increased safety.

As stated in reference to Todd's post, no need on putting Load range "E" tires with a reserve of 75% (think it was). Obviously a Load Range "D" makes most sense as you stated Load Range "C" provide a negative reserve (due to over loading) in many cases.

Would you agree, if owners didn't overload and exceed the GVWR (Manufacturer has taken GAWR into account) then the OEM equipped tire should be adequate.

[Tireman9]

Originally Posted by Bcborn

As you stated trailer tires typically end up with a negative reserve (a result of an over loaded the trailer). We could talk about improper weight distribution too (will leave that for another day). Bottom line most issues are human error

My trailer loaded with gear comes in close to 5700lbs, a far cry from the maximum of 7000lbs. I'm probably not the only owner that never experiences the maximum weight capacity. Thus the question do we need to inflate to the tire maximum. As you stated it is good practice to inflate to the maximum if you do not know the exact maximum load on any given tire. Not to mention increased reserve is increased safety.

As stated in reference to Todd's post, no need on putting Load range "E" tires with a reserve of 75% (think it was). Obviously a Load Range "D" makes most sense as you stated Load Range "C" provide a negative reserve (due to over loading) in many cases.

Would you agree, if owners didn't overload and exceed the GVWR (Manufacturer has taken GAWR into account) then the OEM equipped tire should be adequate.

Yes OE tires should be adequate. BUT Are you sure your load split, side to side does not end up with one axle end supporting more than it's rated max load? The only way to know that for sure is to get "4 corner weights" which takes some planning and effort. Short term you could calculate 53% of each axle weight and you can get each axle weight at regular truck scales. The 53% number will cover most applications. If you are at or close to the tire max that would increase the importance of learning the actual loading on each tire.


I still would like to see no tire having more than 80% of the load it is rated for at the cold inflation you use as this would get you closer to the loading found on most non-RV vehicles which hopefully would result in longer tire life.