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Old 06-10-2024, 01:39 PM   #1
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Need help understanding Tire Pressure PSI Chart

I found this Goodyear Tire Chart for the G670 RV tire. Please help me understand the chart. I also have the weight on my RV. I am under the weight limit for all
Axles, as well as GVWR.

For the STEER weight, do I divide that weight by “2”? Then look at the Goodyear Chart and look at the weight (is that PER tire)?

For the DRIVE AXLE, do I divide that number by “4”? Then look at the Goodyear Chart and look at the weight (is that PER tire)?

For the COLD PSI pressure, as long as it has not been driven (early in the morning). Does the outside temp have any effect on the PSI? (It is now around 80 degrees her in Vegas early in the morning).

I had always set my PSI at 84 all around. But my tires looked like it can use some more air.

Thought??
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Old 06-10-2024, 02:09 PM   #2
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THOR #28908
The S and the D on that chart stand for single and dual wheels. That’s why certain trucks and RV’s the air pressure is higher in the rear than the front even though they’re really designed to carry the same amount of weight. Dual tires when aired up at a the same psi actually carry less weight than a single tire does. so if you read across that chart depending on which tire size you have, at 100 psi the front tire will carry “x” amount of pounds per tire and the rear tire will carry “x” amount of pounds per tire. There is a tire pressure placard that should be on your rig. Somewhere near the weight capacity of the RV. More air is always better than less. Overloading the tire because the inflation isn’t high enough, especially on steel belted sidewalls is very dangerous. Tire pressure should always be set when it’s cool outside as much as you can. It can increase 10 or more pounds which is why tire has a max inflation because the manufacturer knows that it will increase his temperature rises.

Hope that makes sense
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Old 06-10-2024, 02:18 PM   #3
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Quote:
Originally Posted by ador View Post
I found this Goodyear Tire Chart for the G670 RV tire. Please help me understand the chart. I also have the weight on my RV. I am under the weight limit for all
Axles, as well as GVWR.

For the STEER weight, do I divide that weight by ď2Ē? Then look at the Goodyear Chart and look at the weight (is that PER tire)?

For the DRIVE AXLE, do I divide that number by ď4Ē? Then look at the Goodyear Chart and look at the weight (is that PER tire)?

For the COLD PSI pressure, as long as it has not been driven (early in the morning). Does the outside temp have any effect on the PSI? (It is now around 80 degrees her in Vegas early in the morning).

I had always set my PSI at 84 all around. But my tires looked like it can use some more air.

Thought??
You have it figured out.
Yes is the answer to all your questions.
84 PSI sounds right for your ACE, our placard says 82 all around but we are on the 16K chassis.
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Old 06-10-2024, 02:23 PM   #4
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Hello SD. The placard said 82psi Cold. But I think with the actual weight informationI got per axle, and the G670 tire chart PSI, I can safely adjust the tire pressure accordingly. I just want to make sure I understand it clearly. Thanks for your response.
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Old 06-10-2024, 02:40 PM   #5
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Yep! As Ace said you got it correct. It’s better to error on the side of more air than less air. Unless they’re Set at their max inflation, I always inflate a few pounds higher five or so just to make sure I’m good. Adding a few extra things into the RV for a trip that you don’t really think about can make a big difference
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Old 06-10-2024, 05:15 PM   #6
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I always add ten psi to the minimum required psi per the weight chart. Until you get a four point weight done, you do not know just how much weight is on each tire or dully tire set. When I finally got four point weighted, it turned out my driver side was heaver than the other. The ten extra psi was the proper psi for the weight do to the weight on the driver side. Some RV's are almost equal, but you do not know until you have four point weighing done.
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Old 06-10-2024, 05:19 PM   #7
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There's a sticker on your wall.
Anything within 10psi of that is fine.


Unless you wring hands over your daily driver psi there is no need to do hand wringing on your rv.

Hint:
Some people treat psi like a hobby.
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Old Yesterday, 09:40 AM   #8
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The conclusions you took are all right.
Mayby wrong about the single/duallload thing.

But you forget to build in a reserve.
Needed for next:
Unequal weight R/L on the axle .
Inacurate reading of pressure and weight.
Pressure loss in time.
Going over 75 mph for your tires

When I make a cold pressure axleload list I make them for a bit virtuall higher speed, for your tires for instance 87 mph ( not saying you must drive that) and give 90% of calculated axleloadcapacity for the cold pressure.
This then still. Gives acceptable comfort and gripp, so I concluded from reactions.

Then you dont need to do pre or after calculations yourselves.

Then you " only" have to determine the axleloads (better would have been axle-end loads) 99% accurate, wich you did by weighing.
But did you weigh fully loaded?
This determining axle(end) loads accurate in your use, is your responcibility.

I assume the trailerweight on the weightslip is the tag axle, but correct me if wrong. Then same tires.

And you have the top tires in the list so maxload S 3970 lbs / D 3750 lbs. At 110 psi , but also correct me if wrong.

I estimate pressures determined with use of my made list will come to about 100 psi, and still acceptable comfort and gripp.


Then about what cold pressure is.


Best definition is when temperature of gascompound in tire is practically the same as the outside ambiŽnt temperature.

That is when not driven long enaugh and no external factors, like sunshine on tire.
This last has become the definition .

Now there are 2 camps in if recomended cold pressure is for a certain ambiŽnt temperature.

Camp 1 is largest, and states that you have to fill the determined needed cold pressure at any ambiŽnt temperature , be it 20 degr F or 110 degr F . Gives you a chalance to fill up and blead down when traveling trough extreme ambiŽnt temperature regions.

I am in the second smaller camp, that states that determined needed cold pressure or recomended is for an index temperature given
Read index temperatures ( As RIMEX cals it) between 60 degr F/ 15bdegr C upto 77 degr F / 25 degr C .
Mostly 20 degr C / 68 degr F.

Porche and BMW give on tmps screen besides the pressure also the recomended pressure calculated from index temp ( most likely 68 degr F) to the temperature in tire ( also sent by the sensors) . Some tmps systems for motorcicles give on screen pressure calculated back to 20 degr C / 68 degr F.

A tmps system is yust a little computer in wich the designing ingenieur can put software he thinks needed.

This then can give differences between tmps reading and gauge-reading.

My opinion based on conclusions I took in time is that you can let the pressure flow with temperature change.

When hot the higher pressure gives lesser deflection, so heatproduction at same speed, wich compensates the lesser cooling down by lesser temperature differences between tire-material and in-and out-side tire air ( or other gascompound) .
So never blead down cold or warm pressure on a hot day.


When cold ambiŽnt the other way around.
More heatproduction and more cooling down.

But then you may highen up to determined needed for reasons of riding quality and fuell saving, but not needed for savety of tire, so no overheating tire-material, wich is main goal of tiremakers when determining needed pressure.

If the camp 2ers are right, you only have to check if pressure and temperature are in line, and dont need to fill up and blead down maniacally.

Tmps systems give a direct warning when pressure drops 2 psi .
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Old Yesterday, 04:05 PM   #9
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Once again I ask;
If you all(a completely non specific you encompassing anyone who wants to respond who has a penchant for trivial tire adjustment)don't do the same fret over your daily driver;
Why do you do it to your rv?

Is it abject fear?
A hobby?
A misunderstanding of world wide experiences involving 100,000,000,000 miles on heavy vehicles?
A distrust of the very infallible engineers touted elsewhere when touting is to the advantage of the touters conceptions?

I truly don't get it, but I sway easily.
Sway me.

You're scaring/scarring newbs.
You can tell by the questions they ask that were never questions in their past 40 years of driving experience.
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Old Today, 01:53 AM   #10
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I have the G670 RV tires an run at 82 cold all the time. I played the weigh game only to find out that per the chart I would have to exceed the axle weight for the F-53 to require any more air pressure.

My tires are 6 years old and I am in the mist of dumping my Goodyears. I had blowouts on 2 of the 6 in. I am going with an off brand tire but higher rated tire i.e. H rated vs G, 120 psi max vs 110, 81 mph vs 75 and more weight load. I have the new tires in my garage just need to schedule to have tire guy come by and put them on.

BTW, I finally graduated from my cheapo China made TPMS, I got a brand new RVi Tire Patrol 6 tire system for $100
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Old Today, 04:43 AM   #11
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To the poster that adds 10 psi, I'll ask why? It makes no sense to me.
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Old Today, 09:13 AM   #12
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That 10 psi extra , you probably refer to me with probably 100 psi outcome where topicstarter determined 85 psi with the officiall list.

The poster before you had 2 failing tires with a trusted brand, wich could have been courced by using to low pressure for the real load on tires ( can also be yust punctures) wanted to swich to H load , but mayby higher pressure then 82 psi on his G-loads, would have prevented the 2 failing tires.

So in my former long post I explain why you need to build in a reserve.

Following the list topicstarter gets a minimum pressure for the assumed load on tire for max speed 75 mph
A bit higher speed and or more weight on tire, and tire deflects to much and to much heatproduction, wich gives overheated tire-material , little beginning internal cracks, that tear further in time , untill mayby only after 3 years that far that tire blows or treath separates.
Then the relation to that overheating situation is long forgotten, and other factors are blamed.


2 posts before yours is sayd. , why on RV and not on normal car. That is because RV tires are often driven to the max constantly. Normal cartires real weights on tires 99% of use way below max weigt for fully loaded, so much less overheated tires.
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Old Today, 12:36 PM   #13
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Quote:
Originally Posted by jadatis View Post
That 10 psi extra , you probably refer to me with probably 100 psi outcome where topicstarter determined 85 psi with the officiall list.

The poster before you had 2 failing tires with a trusted brand, wich could have been courced by using to low pressure for the real load on tires ( can also be yust punctures) wanted to swich to H load , but mayby higher pressure then 82 psi on his G-loads, would have prevented the 2 failing tires.

So in my former long post I explain why you need to build in a reserve.

Following the list topicstarter gets a minimum pressure for the assumed load on tire for max speed 75 mph
A bit higher speed and or more weight on tire, and tire deflects to much and to much heatproduction, wich gives overheated tire-material , little beginning internal cracks, that tear further in time , untill mayby only after 3 years that far that tire blows or treath separates.
Then the relation to that overheating situation is long forgotten, and other factors are blamed.


2 posts before yours is sayd. , why on RV and not on normal car. That is because RV tires are often driven to the max constantly. Normal cartires real weights on tires 99% of use way below max weigt for fully loaded, so much less overheated tires.
To be clear, I stated my cold psi as 82, which is what is recommended on yellow sticker and my weight loads per Goodyear chart. I never come close to sniffing excess weights. I have only had weighs to placate those that insist on weighs just so I can say I have weights to prove to myself that in my real world situation it is meaningless, unless I stop in Fort Knox Kentucky and collect some gold bars

Both of my tire failures were in fact blowouts, not punctures. Both times I had TPMS systems; nothing noticeable was going on. 1st time with a working cheapo China made TPMS and most recently with high end RVi Tire Patrol system. IMO, I think if my cold psi had been 92psi or 10 psi more, my situation may have been worse.

Regardless, I blame my very expensive Goodyear RV G670 as perhaps being too old (they were made in 2018 with 35,000 miles? Maybe 6 years is normal? but I decided to replace them all now and to not buy the OEM replace. My new tires may end up being worse but I at 40cents on the dollar I am about to find out.

In my book the tires I have are made by the largest tire mfg in the world, they have US DOT certification, and they are rated better in every category than OEM.

The 2nd tire blowout took out a rear compartment and I loss all of it's contents. $1,400 repair & damages. I am fully ensure with 0$ deductible but I am planning to pay out of pocket as to not file a claim. I am worried about my rate increasing? This is 2nd blowout within a year and I have already had 2 windshield claims; so I may be pushing it.

Soon I will know how the ride differently. Up to this point I have only ridden on one of my off brand tires because I had it as a spare. If it make he Goodyear folks feel better, when my change out is done my previous Goodyear spare made in 2020 will return as my new spare while I have all 6 of the H rated tires. If I go two years with no issues on my new tires, I will buy a brand new 7th H rated tire and toss the Goodyear spare as it would then be 6 years old.

Also for the cost, I can plan to change my off brand tires every 4 or 5 years if necessary and still save money from buying a set of the Goodyear RV G670s
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Old Today, 02:32 PM   #14
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Quote:
Originally Posted by jadatis View Post
That 10 psi extra , you probably refer to me with probably 100 psi outcome where topicstarter determined 85 psi with the officiall list.

The poster before you had 2 failing tires with a trusted brand, wich could have been courced by using to low pressure for the real load on tires ( can also be yust punctures) wanted to swich to H load , but mayby higher pressure then 82 psi on his G-loads, would have prevented the 2 failing tires.

So in my former long post I explain why you need to build in a reserve.

Following the list topicstarter gets a minimum pressure for the assumed load on tire for max speed 75 mph
A bit higher speed and or more weight on tire, and tire deflects to much and to much heatproduction, wich gives overheated tire-material , little beginning internal cracks, that tear further in time , untill mayby only after 3 years that far that tire blows or treath separates.
Then the relation to that overheating situation is long forgotten, and other factors are blamed.


2 posts before yours is sayd. , why on RV and not on normal car. That is because RV tires are often driven to the max constantly. Normal cartires real weights on tires 99% of use way below max weigt for fully loaded, so much less overheated tires.
The placard PSI is for the coach at GVWR. If you are below GVWR then you already have a reserve built in. If you run at or near GVWR maybe a 5 PSI would be a good safety reserve.

But adding an extra 10 PSI and running significantly below GVWR gets you a rock hard. teeth chattering ride and squirrely steering so that would be the next complaint.
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