Tire Pressure on Goodyear Endurance

[field & stream]

Originally Posted by SYC2Vette

The load rating for the Goodyear Endurance at 65 psi exceeds both the axle and the total trailer GVW so yes they match just like the OEM tires on my Canyon which exceed the GAWR for my Canyon at the GM specified 35 psi even though they are rated to carry max load at 45 psi. Same principle on my K2500 with 80 psi tires and much lower door sticker psi to meet GAWR. Oh well, the AS recommended pressure works for us.

I get that all the numbers you reference match, and in my opinion that is a correct pressure for your trailer.

The numbers that don’t match — and which I think are a source of confusion — are the number on the metal tag on the trailer (65) and the number on the tire (80). Adding to confusion is Airstream’s statement that “… a maximum inflation specification (note that this is singular) is found on the trailer’s exterior on a metal tag riveted to the lower front, roadside of the trailer, as well as on the original equipment tires.” They reference a single specification, then send you to two places that don’t match.

[bweybright]

Originally Posted by jadatis

I claim to know how those pressure loadcapacity list work, and ST lists , the question is what not is wrong in these lists.

And you dont need rocket science to make those lists, I did it already for you.

Made my own lists with extra save formula, gives lower loadcapacity's for the pressure then the in Europe used formula for every kind of tire, but still no reserve added.
A map " given per tire, per axle single, per axle dual, so pick the list you think most handy.
Per tire also a collection of all the loadranges.
All pdf.



And asking for contact to do stuff has me wondering about troll or scam??? You totally need to clarify who you are I think.


Use it like this for ST .
Seach loadrange on sidewall and look in list for that loadrange (D-load AT 65psi for instance) for the loadindex or maxload in lbs .
Then go 6 loadindex steps down to get maxload for 99mph. ( or not if you wont believe this'" pigheaded Dutch selfdeclared tyrepressure-specialist ")
In that list search the weighed axle- or tire-lbs+11% ( depending of axle or tire list is used).
Above or below that the pressure I would recomend.
Always take the loadcapacity higher then you determined load.

https://1drv.ms/f/s!AtzmkuDu4Calhy1JOdG0mFbnyEF9

I get that you are very confident in your knowledge, and obviously not from the US given your language abilities. Please let us all know about your training, skills, and knowledge base to be trying to challenge a known US tire manufacturer engineer on this thread? I quite honestly looking at your post for contact to run numbers was thinking you are a troll thread to scam us? Just asking for you to clarify and justify your recent statements against a solid and verified tire manufacturer engineer? All due respect, but you need to clarify your basis of educated statements. Sorry if I am out of line.

[2012FB]

It is time to go back to arguing about 1/2 ton verses 3/4 ton. These threads always digress a bit to far. Good information has been put out and with respect it is up to each to decide. Besides it would appear everyone has or had.

[jadatis]

Originally Posted by bweybright

I get that you are very confident in your knowledge, and obviously not from the US given your language abilities. Please let us all know about your training, skills, and knowledge base to be trying to challenge a known US tire manufacturer engineer on this thread? I quite honestly looking at your post for contact to run numbers was thinking you are a troll thread to scam us? Just asking for you to clarify and justify your recent statements against a solid and verified tire manufacturer engineer? All due respect, but you need to clarify your basis of educated statements. Sorry if I am out of line.

End 2007 my tirepressure-story began as one of my unorthodox proyects, that mostly end after a while, but kept hanging in it .

Had a motorhome and joined Dutch camperforum ( in the netherlands we call them camper or kampeer-auto)
Here many overloaded campers on rear axle , because most GAWR ( MTM) are 3500kg/ 7700lbs, because most only have B driverslicence for up to 8 passengers and GVWR 3500kg.
Then often recomended 5,5 bar/80psi all around.
My idea was that if you only had 80% of maxload on tyre, that you need only 80% of the " maximum" pressure" given on tires.

Mailed Vredestein about it , and after some corespondence, got copy of page 14vv of designers guide ETRTO ( European Tyre & Rimm Technical Organisation, your TRA) with formula and system for calculating pressure for a load on tire, and went running with it.

That formula showed that even a little less is enaugh then, but calculating lineair is not even that bad.

Before that I never minded tires and pressure, but got wiser in time by contacting people who seemed to know more about it. Learned myself Excell to maje spreadsheets for it, with help of forum-users on different fora.

Also TM9 and Capriracer.
An article of J C Daws about new kind of calculation and compare with those used in Europe , made me wiser, and I also contacted him.
Got much usefull info of him in time, and he apriciated my idea about the speed/ maxload relation.
Unfortionally he died february 2017, so can not ask him anymore.
At a certain moment I thougt to know that much about it , that I began to call myself " pigheaded Dutch selfdeclared tyrepressure-specialist " so people could set my information in the right context.
I dontt claim to know everything, even Einsteins theory's can be proven wrong once, but all based on administratical research.

But found out , that history made the systems of tires and tirepressure a bit messy and confusing, so I try to clear that up a little with my reactions on fora.

[Bill M.]

The tire pressure dilemma did not start until the new Endurace tires came out. Before that all the ST tires that were run on Airstreams had a max inflation of 65 PSI. And a speed rating of 65 mph. I do not believe it takes 15 more psi to support the same load on the same size tire. But it probably does take that to support the higher speed rating. They want less deflection so the tires will not heat as much. So maybe how fast you run figures into the tire pressure decision.

[Rich Jenkins]

So, more on the subject of "do I understand this correctly" and not "what pressure should I use", can I ask you guys to look over the attached chart?

I haven't been able to weigh my rig (2022 GT23FBT) yet, so I used the GVWR, figuring it should not be above that. I added a margin (15%) to that, then computed the "load" assuming equal distribution on each tire. I then looked up the load capacity (I think its the load capacity?) of the tires from the famous inflation chart.

Based on that, I calculated the percent load I am at, for each of the common pressures you see (80 psi down to 65 psi) folks cite they run their GYE on.

Does this make sense?

[ROBERT CROSS]

Hard to believe air can be so confusing. 🤔🤔
I'm very glad I don't have the complications in my head that interrupt common sense.
I don't 'adjust' to load, ck cold and set to 68 +- a few.
Dual axle...the lower the psi the more pronounced the tire sidewall shear force. BSTS.
Your common sense may vary.🤪

Bob
🇺🇦🇺🇸🇺🇦

[GettinAway]

I’ve been running 70 psi in my GYEs for two years. No popped rivets, no open doors or cabinets. I notice with my TPMS that the two tires on the sunny side of the trailer run warmer. I have the Dill TPMS, and have had three false alarms in the last two years. It’s not clear if the alarms are for pressure or temperature.
So, my question is, what’s the highest running pressure you all are comfortable with? One of the reasons I’m still at 70 is because when I went lower the temps were higher.
I’m hoping the tire pressures don’t contribute to front end separation.
There, now I’ve made this already complicated thread even more so.

[Mollysdad]

Originally Posted by Llando88

So, more on the subject of "do I understand this correctly" and not "what pressure should I use", can I ask you guys to look over the attached chart?

I haven't been able to weigh my rig (2022 GT23FBT) yet, so I used the GVWR, figuring it should not be above that. I added a margin (15%) to that, then computed the "load" assuming equal distribution on each tire. I then looked up the load capacity (I think its the load capacity?) of the tires from the famous inflation chart.

Does this make sense?

IMO, no.
Why take GVWR and divide by four? First, calculate how much of the GVWR is riding on the hitch, not the tires, and subtract that.
Why have a 15% fudge factor? "Correct" shouldn't need a constant (K).

But, my sensibilities tell me to avoid threads over 50 posts, so I'll bid Adios, Aloha, Hasta la Bye-Bye.

[ROBERT CROSS]

Originally Posted by GettinAway

I’ve been running 70 psi in my GYEs for two years. No popped rivets, no open doors or cabinets. I notice with my TPMS that the two tires on the sunny side of the trailer run warmer. I have the Dill TPMS, and have had three false alarms in the last two years. It’s not clear if the alarms are for pressure or temperature.
So, my question is, what’s the highest running pressure you all are comfortable with? One of the reasons I’m still at 70 is because when I went lower the temps were higher.
I’m hoping the tire pressures don’t contribute to front end separation.
There, now I’ve made this already complicated thread even more so.

FWIW...just me.

I have my TPMS temp warning set at 150* I watch it religiously for tire warnings, (IMHO better than psi)
I'll worry if I see a 15-20 degree difference. "Cloudsplitter" has had no 'tire pressure' damage...2003-2022.👍

Bob
🇺🇦🇺🇸🇺🇦

[richard5933]

Originally Posted by Mollysdad

IMO, no.
Why take GVWR and divide by four? First, calculate how much of the GVWR is riding on the hitch, not the tires, and subtract that.
Why have a 15% fudge factor? "Correct" shouldn't need a constant (K).

But, my sensibilities tell me to avoid threads over 50 posts, so I'll bid Adios, Aloha, Hasta la Bye-Bye.

It's not a fudge factor - it's a buffer.

Why? Because not all wheels will carry the same load all the time. Road conditions, loading, turns, etc. will vary the amount of downward force being applied and the extra bit of air pressure ensures that you have enough buffer to accommodate these things.

[Bill M.]

"I’m hoping the tire pressures don’t contribute to front end separation. "

I am going to guess that going though a sharp dip with a stiff lash up is the main factor for front end separation. Like loading on a ferry and stuff like that.

[jadatis]

Originally Posted by Llando88

So, more on the subject of "do I understand this correctly" and not "what pressure should I use", can I ask you guys to look over the attached chart?

I haven't been able to weigh my rig (2022 GT23FBT) yet, so I used the GVWR, figuring it should not be above that. I added a margin (15%) to that, then computed the "load" assuming equal distribution on each tire. I then looked up the load capacity (I think its the load capacity?) of the tires from the famous inflation chart.

Based on that, I calculated the percent load I am at, for each of the common pressures you see (80 psi down to 65 psi) folks cite they run their GYE on.

Does this make sense?

Adding first 15% is not that bad for tandem axle, because besides R/L different per axle, also weightdifference between the axles is possible.

But then you forget that minimum 10% must be on towbar to american rules, and youvtake that 15% from GVWR.

Then you calculate what percentage that GVWR+15% is of loadcapacity belonging to the pressure. So this gives much more reserve then needed.

What you should do is yust take 90% of GVWR-10% ( towbar) and calc the percentage of that to the liadcapacity, and search for the pressure at wich this is 90% , or if you want 15% reserve, as you planned, look for 1/ 1.15= 87%.
Now you are doung it double.

But now my pigheaded idea about the ST lists come in view. It leads to to high loadcapacity, so still overheating at 65mph for the lower pressures.

If you use my made lists, you have to look for the E-load list AT 80 psi, and go to loadindex 117 is 2835lbs maxload, and then for max 65mph, and reserve is that 15% you use.
But better is to substract 6 loadindex steps so look in 111 loadindex list / maxload 2403 lbs.
Then take these loadcapacity's over to your spreadsheet, and take the pressure at wich it is 87% or easyer is first add 15% and search that back in my list, and dont use your spreadsheet.

Hope I did not make it more complicated

[GettinAway]

Originally Posted by ROBERT CROSS

FWIW...just me.

I have my TPMS temp warning set at 150* I watch it religiously for tire warnings, (IMHO better than psi)
I'll worry if I see a 15-20 degree difference. "Cloudsplitter" has had no 'tire pressure' damage...2003-2022.👍

Bob
🇺🇦🇺🇸🇺🇦

Thanks. I intended to say highest temp, not highest pressure. Glad you knew what I wanted to say. I was getting concerned when I was over 120. Tough to do on a hot day.

[CapriRacer]

Originally Posted by Bill M.

The tire pressure dilemma did not start until the new Endurance tires came out. .....

No, tire pressure has been a hot topic since - well - forever. It's one of the few things people have a choice on. After all, you just can't change the size of the lugnuts!

This particular version is because the trailer manufacturers finally stepped up and realized the rest of the world - meaning car and truck manufacturers - were using good engineering principles and quit undersizing tires. We are now in the midst of that changeover repercussion.

Ya see, nowadays all the car and truck manufacturers produce vehicles with appropriately sized tires and inflation pressures - and that is reflected on the vehicle tire placard. Only occasionally does someone question the car or truck manufacturer's specification - usually pickup owners.

In an ideal world, trailer manufactures would have been just as diligent and people could follow the placard specification without questioning it.
Unfortunately we don't live in that world.

[gypsydad]

Originally Posted by jadatis

Adding first 15% is not that bad for tandem axle, because besides R/L different per axle, also weightdifference between the axles is possible.

But then you forget that minimum 10% must be on towbar to american rules, and youvtake that 15% from GVWR.

Then you calculate what percentage that GVWR+15% is of loadcapacity belonging to the pressure. So this gives much more reserve then needed.

What you should do is yust take 90% of GVWR-10% ( towbar) and calc the percentage of that to the liadcapacity, and search for the pressure at wich this is 90% , or if you want 15% reserve, as you planned, look for 1/ 1.15= 87%.
Now you are doung it double.

But now my pigheaded idea about the ST lists come in view. It leads to to high loadcapacity, so still overheating at 65mph for the lower pressures.

If you use my made lists, you have to look for the E-load list AT 80 psi, and go to loadindex 117 is 2835lbs maxload, and then for max 65mph, and reserve is that 15% you use.
But better is to substract 6 loadindex steps so look in 111 loadindex list / maxload 2403 lbs.
Then take these loadcapacity's over to your spreadsheet, and take the pressure at wich it is 87% or easyer is first add 15% and search that back in my list, and dont use your spreadsheet.

Hope I did not make it more complicated

Thought someone said it's not "rocket science"...then why make it so involved?? Pretty simple from reading everyone's input...(over the years), even though "some" still want to make it more complicated? If your concerned, call the tire manufacturer. ST has a stiffer sidewall designed for the potential stresses of towing a trailer. If you want to run at "MAX PRESSURE" and you feel you don't have any negative problems like popped rivets, door hinges/ latches breaking, cupboards comming loose from bulkhead or ceiling, etc. like has happened to many of us; then go for it! If you want to give your trailer a "softer" ride, drop down 10-15 PSI, cold. Like the revolving- "which WDH" or "which TV" or "which best tire" threads, think we beat this one to death...again.

[jadatis]

But dropping down 10 or 15 psi is a camble.
You only have to calculate it once, because weight stays moastly pretty well the same trough the years.

And I did the rocket science for you, you only have to give acurately determined data.

[jadatis]

Been playing with an older spreadsheet , for cimpsring different calculations,and made image of the outcome

Its for the sise ST 225/75 R 15 .
At the bottom taken over from Goodyear list.
Above that using power I expected to be used and for 2830lbs AT 80 psi. E- LOAD
Above that for 2150 lbs AT 50 psi C-load
And on top the calculation used in Europe for all kind of tires.

Then you see jumps at 35psi ( B-load) and 65 psi ( D- load, and 60 psi the person who calculated it with his sciencetific calculator probably dud a miswriting , should have been 2390lbs instead if 2380 .
Then the 80 psi is calculated from 50 psi expanded , bottom 2 calculations almist exactly rhe same.

This ofcource is no 100% prove, but makes it plausible that these calculations are used , and maxload of 35psi and 65 psi replaced the loadcapacity of those psi.

Then this is still for 65mph the maximum loadcapacity for the pressure, above that overheating of tire when driving faster then 65mph.
But only if calculated with the European formula, the ST formula , originally meanth for diagonal tires in the lower pressures even at lower speed overheating with the loadcapacity's given.

So I did not even lowered the maxload by 6 LI steps ( 15%) , as to my pigheaded idea is needed to give max reserve. Also not gave my determined formula.

At the top the universal formula both ways, and at the bottom the used powers in time.

[gypsydad]

Originally Posted by jadatis

Been playing with an older spreadsheet , for cimpsring different calculations,and made image of the outcome

Its for the sise ST 225/75 R 15 .
At the bottom taken over from Goodyear list.
Above that using power I expected to be used and for 2830lbs AT 80 psi. E- LOAD
Above that for 2150 lbs AT 50 psi C-load
And on top the calculation used in Europe for all kind of tires.

Then you see jumps at 35psi ( B-load) and 65 psi ( D- load, and 60 psi the person who calculated it with his sciencetific calculator probably dud a miswriting , should have been 2390lbs instead if 2380 .
Then the 80 psi is calculated from 50 psi expanded , bottom 2 calculations almist exactly rhe same.

This ofcource is no 100% prove, but makes it plausible that these calculations are used , and maxload of 35psi and 65 psi replaced the loadcapacity of those psi.

Then this is still for 65mph the maximum loadcapacity for the pressure, above that overheating of tire when driving faster then 65mph.
But only if calculated with the European formula, the ST formula , originally meanth for diagonal tires in the lower pressures even at lower speed overheating with the loadcapacity's given.

So I did not even lowered the maxload by 6 LI steps ( 15%) , as to my pigheaded idea is needed to give max reserve. Also not gave my determined formula.

At the top the universal formula both ways, and at the bottom the used powers in time.

Crazy how some folks who don't even own an Airstream, continue to post here how smart they are on some topics...likely never encountered the popped rivets, broken latches, etc...etc...etc...time to move on for sure now!

[hddeering]

10 watt solar panel on TV dash works for us.