Goodyear Endurance

[BlackAces]

Originally Posted by A W Warn

S4.2.2.1 says the "sum" of tires load capacity should equal 100% GAWR. So as a minimum, an individual tire on a two tire axle must support a minimum of 50%.

Yes, true. However, the standard does not assume anything. It's a flat statement. That's because an axle may have more than two tire/wheel assemblies fitted to it.

[BandLAir]

I have also had this question and not gotten very good answers. Goodyear publishes a "load-inflation table" for these tires so, based on our previous motorhome experience, I thought I should use it to set the pressures after having the trailer weighed, fully loaded. BUT, I also found a paragraph in a Goodyear brochure for these tires that says they should be inflated to the max sidewall pressure. Apparently this results in a stiffer sidewall, which is needed do to the sideways motion of trailer tires (sway). Our tires have a max sidewall pressure rating of 80 PSI. Our dealer set them at 75 PSI. I lowered them to about 72 PSI (on a cool day), which leaves room for the pressure to rise under higher ambient temperatures without exceeding the max rating.

[Adventure.AS]

Originally Posted by BandLAir

... BUT, I also found a paragraph in a Goodyear brochure for these tires that says they should be inflated to the max sidewall pressure.

Can you pl awe provide the link to that document?

[jadatis]

If you calculate the pressure for a ST-tire, as if its a LT tire with same sises and loadrange and for 160 km/99m/h ( some LT have lower fi N for 87mph), They last yust as long, and are yust as save as LT.


In the pressure/loadcapacity list of Endurance, same calculation is used as the old ST of Goodyear. In fact they yust expended the old list with the higher pressures. That is the reason why you read the same pressure for a load as in the old list.


And that is a wrong thing , first the calculation that leads to lower pressure for the load, or higher loadcapacity for the pressure.
Second is that they calculate for one loadrange in the same sise, and overwrite the other loadranges with the maxload of that loadrange.
For instance list calculated with the old formula for diagonal tires( for who is interested L0adcapacity=( Pressure/reference-pressure)^0,585 x maxload, the 0,585 is a power like 0.5 is root, and 2 is square) for D-load, and B-(35psi), C-(50psi),E-(80 psi) overwritten with their belonging maxload.
See that yourselfes that the loadcapacity makes a hickup at those pressures.


If you calculate as if LT, and add first 10% reserve to the real load on a tire, the endurance in E-load often comes to 80 psi, and that is why that is standard adviced/prescribed.
But for a tandemaxle Airstream TT I once calculated that even 60 psi gives all the reserves and durability.
Also official institutes like to use rules of tumb.
Most forum users have a religius trust in the information of those institutes.

And because its never ( now never?) unsave to use the max , it saves them many responcibility claims.

[CapriRacer]

Maybe I need to step in here to clarify a few things:

First, those load/inflation charts are NOT brand specific! In this case, the ST charts are published by the Tire and Rim Association (TRA) and republished by Goodyear. TRA is the tire standardizing organization for the US and everyone who manufactures tires in the US is a member - and while it isn't mandatory that everyone use those standards, not only do they pretty much always do, it would be foolish not to. Even the US government references TRA tables in its regulations.

Second, the result of using those charts is a MINIMUM inflation pressure - NOT a recommendation.

HOWEVER, it is not only good engineering practice to specify MORE, using more reduces the forces inside the tire trying to tear the tire apart. We call those forces interplay shearing forces.

[out of sight]

Originally Posted by BandLAir

I have also had this question and not gotten very good answers. Goodyear publishes a "load-inflation table" for these tires so, based on our previous motorhome experience, I thought I should use it to set the pressures after having the trailer weighed, fully loaded. BUT, I also found a paragraph in a Goodyear brochure for these tires that says they should be inflated to the max sidewall pressure. Apparently this results in a stiffer sidewall, which is needed do to the sideways motion of trailer tires (sway). Our tires have a max sidewall pressure rating of 80 PSI. Our dealer set them at 75 PSI. I lowered them to about 72 PSI (on a cool day), which leaves room for the pressure to rise under higher ambient temperatures without exceeding the max rating.

I agree. Tire pressure recommendations should not only be about getting the best ride or the longest tire life but also about achieving the best handling of the rig.

[Bill M.]

Been on a couple of caravans with people with new trailers. Cabinets falling off walls, rivets popping, things bouncing out of place. But the tires, at 80 psi, seem to be doing okay.

My trailer is 30 years old and came with bias ply tires and an inflation sticker that says 43 lbs. Is the difference in radial tires such that it now requires 80 psi to hold it up with the same size tire?

I am not interested in doing :"the best thing for the tires". What I want is for them to last 4 years without damaging the trailer, either from beating it up, wrecking from poor traction, or from failing and damaging it.

[Fair_Enough]

Has anyone noticed that badkat started this and hasn't come back in. By the way, I do what I think is right and only read the first couple of replies. If you don't believe the dead can be raised, just create a post that mentions tires, truck brands or diesel vs. gas.
WW

[ROBERT CROSS]

CR

You are preaching to the 'soft' core. The charts are sacrosanct and never to be ignored.

I have run GYM's @ 65 cold for 15yrs. My only failure was my own fault.(curb whack).
The GYE's are on their 3rd Season at 73 cold and I expect the same performance from them. Narry a pooped rivet or flying woodwork.
A bad axle on our '63 Safari was the reason for the only interior towing damage we have ever experienced.

TETO 🤓

Bob
🇺🇸

WolfW
Come now, that is the normal outcome for most/all of the
what should-I-do threads.

[Mollysdad]

Originally Posted by ChuckFeldt

I think the Endurance tires have a higher load rating than the Marathons. Though I didn't look when they were change out.

Good Year published the exact same inflation chart for Marathons and Endurance.

[ROBERT CROSS]

Originally Posted by ChuckFeldt

I think the Endurance tires have a higher load rating than the Marathons. Though I didn't look when they were change out.

Yes...
They are available in D & E rating. Our AS takes the E.

Bob
🇺🇸

[panamerican]

I had upgraded from "D" to "E" rated tires and I have run on average 70-72psi on all my E rated tires that state max pressure 80psi. I have had zero popped rivets and I've been on some pretty rough roads. I have about 10-15k miles on the tires as they reach year 5 and then I replace them with tires of similar rating. I have been running the Maxxis tires for a bit over 10 years now, mostly due to the Goodyear Marathon debacle, but I do tow sometimes at speeds of 70 mph, may even break upward of 75 for short bursts and the Maxxis is not **really** rated to do that, whereas the Endurance tires are and appear to have an excellent operating record so far and so I will most likely migrate to the Endurance "E" rated tires this spring using the same pressures as indicated.

[jadatis]

Originally Posted by Bill M.

Been on a couple of caravans with people with new trailers. Cabinets falling off walls, rivets popping, things bouncing out of place. But the tires, at 80 psi, seem to be doing okay.

My trailer is 30 years old and came with bias ply tires and an inflation sticker that says 43 lbs. Is the difference in radial tires such that it now requires 80 psi to hold it up with the same size tire?

I am not interested in doing :"the best thing for the tires". What I want is for them to last 4 years without damaging the trailer, either from beating it up, wrecking from poor traction, or from failing and damaging it.

Radial tires need higher pressure for the same load, but not the full 80 psi in this case. I estimate if Bias 43psi, radial about 55psi.


But its posible to tires to last 6 tto 10 years , and pressure so , that no rivets popp, or whatever damage done to the trailer.

[Tireman9]

1. DO NOT lower the cold inflation so the tires never go above the sidewall inflation number when hot. Inflation on the sidewall is the MINIMUM cold inflation needed to support the load number also molded on the tire sidewall.


2. Motorhome MINIMUM tire inflation can be based on the inflation in the TRA tables and the actual measured load with the RV at its heaviest. BUT it is recommended that you add 10% to that inflation number to allow for day to day ambient temp change which will change the cold inflation by about 2% for each 10°F


3. Trailer tires, especially on multiaxle trailers are subjected to different and MUCH HIGHER internal structural loading whenever not traveling in a direct streight line. This increase can result in the tire Interply Shear being 24% higher than in a motorized vehicle with tires that turn based on steering input/ (See Ackerman Steering)


4 Yes Goodyear does agree with my engineering analysis and provide the same recommendations as in my RV Tire Blog March 29 2019 where I said



"I have written a number of times on the advisability of running trailer tires at the inflation molded on the tire sidewall.

Some posts dove deep into the Science behind the recommendation. I know this can make your eyes glaze over so how about just following what Goodyear says in their RV Tires information web page:

"Unless trying to resolve poor ride quality problems with an RV trailer, it is recommended that trailer tires be inflated to the pressure indicated on the sidewall of the tire. Trailer tires experience significant lateral (side-to-side) loads due to vehicle sway from uneven roads or passing vehicles. Using the inflation pressure engraved on the sidewall will provide optimum load carrying capacity and minimize heat build-up."

Sorry but the forum rules here do not allow me to provide hot links to my blog so you will need to GOOGLE to learn more about proper inflation and the science behind Interply Shear.

4. Yes you can run lower inflation if the suspension design of your RV doesn't provide the desired cushioning. This may result in shorter tire life and would IMO require much more involved annual tire inspection to avoid a surprise belt separation which can cost a lot more than a few popped rivets.

[Tireman9]

Originally Posted by CapriRacer

Maybe I need to step in here to clarify a few things:

First, those load/inflation charts are NOT brand specific! In this case, the ST charts are published by the Tire and Rim Association (TRA) and republished by Goodyear. TRA is the tire standardizing organization for the US and everyone who manufactures tires in the US is a member - and while it isn't mandatory that everyone use those standards, not only do they pretty much always do, it would be foolish not to. Even the US government references TRA tables in its regulations.

Second, the result of using those charts is a MINIMUM inflation pressure - NOT a recommendation.

HOWEVER, it is not only good engineering practice to specify MORE, using more reduces the forces inside the tire trying to tear the tire apart. We call those forces interplay shearing forces.

^x2

[jaybauman]

Originally Posted by ROBERT CROSS

CR

Narry a pooped rivet

Me, neither. But then again, I have never eaten a rivet either.





Apologies for the bad humor...now back to the great discussion on tire pressures!

[out of sight]

I keep my tires at 80 psi. So far, after 10,000 miles on the trailer, some over real bad roads, I have yet to see a popped rivet.

[CapriRacer]

Originally Posted by Bill M.

..... My trailer is 30 years old and came with bias ply tires and an inflation sticker that says 43 lbs. Is the difference in radial tires such that it now requires 80 psi to hold it up with the same size tire? ….

No - BUT - There have been quite a few changes in 30 years.

First is that is it likely that the tire size on your trailer has changed. Current tire sizing is a bit smaller (physically), so more inflation pressure is required to carry the same load.

Second is that trailer manufacturers used to specify minimal load carrying capacity in their tires. It's likely that inflation specifications then are too low.

Third is that it was common for trailer manufacturers to underestimate how much stuff folks actually put in their trailers. Ergo, even what they state as load limits for the trailer were inadvertently violated by the user. This also meant the tires could be inadvertently overloaded,

Fourth is that trailer manufacturers covertly specified a 65 mph speed restriction. For some reason they never informed the public. Increased inflation pressure is required for higher speeds.

So your sticker that says 43 psi might have all these flaws, and an equivalent newly manufactured trailer might say 65 psi.

Side note: Are you sure it says such an odd value? Might it say 45?

[Tireman9]

Originally Posted by jaybauman

Me, neither. But then again, I have never eaten a rivet either.
Apologies for the bad humor...now back to the great discussion on tire pressures!

Not sure how rivet problems are the fault of the tires. I thought rivets were a "feature" of AS trailers


Wondering if popped rivets are more likely on older trailers? I have never inspected an AS. What is their suspension? Do they have shock absorbers?


While tires do provide some shock absorbing properties does AS company specify specific brand tires that they have tested that provide the needed shock tolerance?
If tires are suppose to work in place of a set of shocks I would think tires should have been evaluated by the Company as all car companies do and a specific brand selected as the only acceptable brand.

[ROBERT CROSS]

^
X2

Over 50+ years of Streaming, the only cause of rivet failure we had was on our '63 Safari, the torsion axle stopped torsioning due to the rubber losing it's elasticity.
Bumpity, Bump, Bump.

Yes, both the Safari and Classic have shocks.

65PSI GYM 73PSI GYE

Bob
🇺🇸