Goodyear Endurance Tire / Pressure

[Mollysdad]

Originally Posted by DCPAS

interply shear

I'm violating one of my posting rules. "Don't add to a thread after 50 posts".
If I had a dollar for every time I heard "interply sheer" I could buy a new Airstream. It's usually used to explain why GoodYear's chart makes no sense.
Can we stick to the facts?
Goodyear publishes a chart for their tire inflation. If everyone inflated their tires to 80 psi there'd be no need for a chart.
The tires don't know if they're on a flying cloud or an international or a classic.
I'd simply like someone to explain, using the GoodYear chart, how I'm wrong.
I'm wrong a lot, I can handle it. Just don't blame it on interply sheer. Don't you think GoodYear engineers took that into account for their chart? (Which BTW, is exactly the same chart they published for Marathons)
and, if Airstream posts a placard advising their customers to inflate to 80 psi, aren't they in conflict with GoodYear?

You weigh the trailer, determine how much weight is on the tires, divide by 4 (for dual axles) and plug that number into the chart.
Easy-Peasy, right? NO.

To put a finer point on it, I can't imagine towing a 12,000 pound trailer with 225/75 15 tires! But I could be wrong.

[DCPAS]

Originally Posted by Mollysdad

Goodyear publishes a chart for their tire inflation. If everyone inflated their tires to 80 psi there'd be no need for a chart.

I feel and share your pain. To be fair, Goodyear added an asterisk to its chart that reads: "Industry standards for load and inflation are in the process of being revised. These tables are current as of 06/16/17." Not sure when Airstream went to 80psi, but there may be some connection.

[Mollysdad]

Originally Posted by DCPAS

I feel and share your pain.

Thanks! I love a spirited discussion and am willing to adapt.
I get frustrated when people post, "I consulted the GoodYear Endurance chart and so I run 72 psi in my 23'." WUT?

Not sure when Airstream went to 80psi, but there may be some connection.

I can imagine a meeting of the lawyers and engineers. "We need a tire placard, what should we put on it?" "What's the tires say?" "Um, I thought I saw 80." "80 it is! Meeting is over, I got the first round!"

[SSquared]

Originally Posted by Njg

I finally wised up and bought a TST for my 25' Intl Serenity. When doing set-up I ran into questions about setting the maximum temperature alarm and the pressure ranges. I see a lot of debate here. I've always run at 80PSI following the sticker on the trailer, but the conversation has me considering a conservative decrease to 75. My question mainly relates to temperature. Should I leave the default in place or adjust the high temp alarm. I'm running stock Goodyear Endurances. Thanks all in advance.

On my 2013 model TST 507, the temp alarm limit is not adjustable so I never had to choose a setting (the value is around 150F). We have screw-on sensors. As I recall, they don't get over 10 or 20 degrees above the outside air temp. The sunny side is noticeably warmer

[Specsalot]

65# 25'FC RBQ TST Cap Sensor TPMS 65-67 MPH towing speed. Florida summer weather, tires run in the around 72 or 73 PSI. Reasonable ride. Level ride the forward and rear axle PSI's delta is rarely more than 1 PSI.

[stunami]

This thread is very timely for me, since as we speak I am getting new Endurance tires, along with new axle and wheels installed on my 2001 19' Bambi. I too was wondering what numbers to put in my TPMS. When all is done, I will have a 20 year old trailer that has a placard that says max tire inflation 65 and tires that say max tire inflation 80.

I'm not a tire expert, but I believe people are reading the tire chart wrong. People are reading it as "My weight on each tire is X, thus my PSI should be Y." I believe the correct way to read the chart is "If I choose X PSI, then the Max load on each tire is Y." There is a difference.

In my configuration, GVWR is 4500lbs, with approx. 500lb of that tongue weight onto the TV = approx. 2000 lbs. per tire. I haven't taken it to a weigh station, but one side is probably slightly heavier, so maybe 2,200 on the heavy side.

From my reading of the tire pressure chart, I could choose any desired cold PSI between 55 and 80. As I understand it, the lower end will provide a smoother ride on the trailer and the higher end will provide better fuel economy. I'm sure there is a different ideal PSI for best / safest handling, but I have no idea what that would be.

For what's it's worth, I'll start at 75 PSI for the first trip and if things start flying off the walls, then I'll back it down to 70 or 65.

[wulfraat]

65lbs on 15” goodyear endurance for my 30’ international. Tire load is ~1,875lbs per tire when hitched / ready for camping.

65lbs is well north of the minimum inflation pressure for that load based on the goodyear specs.

I’m happy with that [emoji4]

[switz]

I have my own scales so know the actual tire load per tire. I take the the highest number on our 2014 31' Classic which is the street side rear at 2,062 pounds and multiply by 1.2 for a 20% safety margin. The computer says that is 2,474.2 and I round up to 2,500 pounds. If I were using the Goodyear Endurance ST225/75R15 E tires, the table shows 65 psi is good for 2,540 pounds. For my Michelin Agilia CrossClimate LT225/75R16 E tires, I use 80 psi (81 psi would be precise) that can go to 90 psi for 2,680 pounds.

For our 2015 23D International Serenity, the curb side rear is heaviest at 1,376 pound. Foa a 20% safety margin I could look for the air pressure to support 1,650 pounds. The same GoodYear tire above shows that weight to fall between 30 and 35 pounds. I would use 50 pounds as a minimum for these Goodyear Endurance ST225/75R15 E tires. I run 44 psi in our Michelin LTX (P) 235/75R15 XL tires as recommended by Andy Thompson at CanAm in London, Ontario, CA.

One has to remember all the poor engineering that still exists on many models after many years of production continuing the issue. Sometimes I think their engineers are too lazy to look at tire pressure vs load tables. However, if they just take maximum pressure, they need only one sticker for all of the trailers.

The Airstream single axle trailers have the heaviest load per tire of 2,500 pounds for a 19' CB model. That model should be use maximum pressure of 80 psi for 2,830 pound loads as that is about a 13% load safety margin.

[ETroup]

Here is how I calculated the optimal tire pressure for the Goodyear Endurance tires on our AS International 27FB. Notice I rounded the max trailer weight up to 10,000 lbs.

Even though the sticker on the Airstream suggests 80 lbs., that is simply too hard creating a rough and harmful ride for the trailer.

The only caveat is in the case of a flat with no spare and you need to drive with only one inflated tire on a side. I carry a small air compressor that I could use to increase tire pressure if needed in that case.

Normally I run the AS tires at between 60 - 65 lbs and monitor with TMPS.

[gypsydad]

I remember asking both GY and also AS why the "max psi was 80"? I was told by AS, that most folks don't take time to understand the correct PSI, so they put the Max PSI on the trailer so they don't put in 90 or 100 psi!

I remember running close to max PSI on my 25's with Michelins LT's back in the day, and had popped rivets, and some broken hinges. With 28', and my Endurance 15" tires, I started at 75psi when new...but again, popped rivets on first trips, broken shower door hinge, closet door on the floor one trip. Forgot, also had the closet at foot of Twin bed with TV on it, come loose from upper mount... I changed to 50PSI, which was a little over the chart and no issues...called GY to discuss again, and the guy I talked with said there was no "wear" difference in running the recommended PSI from the chart. I now run at 58 cold...again, no issues with wear, nor popped rivets or other issues...happy now on 3rd set of tires on my 2017, 28' FC with over 55K miles...

(is it just me, or do some of these topics keep coming up?

[tjdonahoe]

Originally Posted by Mollysdad

I'm violating one of my posting rules. "Don't add to a thread after 50 posts".
If I had a dollar for every time I heard "interply sheer" I could buy a new Airstream. It's usually used to explain why GoodYear's chart makes no sense.
Can we stick to the facts?
Goodyear publishes a chart for their tire inflation. If everyone inflated their tires to 80 psi there'd be no need for a chart.
The tires don't know if they're on a flying cloud or an international or a classic.
I'd simply like someone to explain, using the GoodYear chart, how I'm wrong.
I'm wrong a lot, I can handle it. Just don't blame it on interply sheer. Don't you think GoodYear engineers took that into account for their chart? (Which BTW, is exactly the same chart they published for Marathons)
and, if Airstream posts a placard advising their customers to inflate to 80 psi, aren't they in conflict with GoodYear?

You weigh the trailer, determine how much weight is on the tires, divide by 4 (for dual axles) and plug that number into the chart.
Easy-Peasy, right? NO.

To put a finer point on it, I can't imagine towing a 12,000 pound trailer with 225/75 15 tires! But I could be wrong.

Really 2830(4)=11200....1500# on the hitch== 10500 on 4 tires

[Njg]

Originally Posted by SSquared

On my 2013 model TST 507, the temp alarm limit is not adjustable so I never had to choose a setting (the value is around 150F). We have screw-on sensors. As I recall, they don't get over 10 or 20 degrees above the outside air temp. The sunny side is noticeably warmer

I have the TST with screw-on sensors as well. I just wanted to make sure I didn't need to lower the high temp alarm and was wanting to access the collective wisdom of the group. If anyone else has sage advice about temp settings I would really appreciate it.

On a slightly related note, has anyone had trouble installing the repeater for the TST inside of the trailer? My OCD side wants to make sure the admittedly nominal battery draw is measured by my Victron battery monitor shunt, which is installed inside..

[GOUSC]

Figured I'd jump on the tire pressure dogpile. I have a 2018 27 FB Globetrotter and Tow with a 2018 GMC Sierra Duramax. RV weights 6,540 with WD / 1,100 Tongue Weight. Steer axle/ 4,560; Drive Axle 5,260.

When I first towed my Airstream I ran 80 psi in Airstream / 75 psi in the rear of the TV. I had rough ride / popped rivets / and developed a front frame separation issue in the Globetrotter. The 75 psi recommended by GMC supports the max weight that the rear axle of the truck can support, 6,200lbs. As others have mentioned, no one is quite sure where Airstream gets their 80 psi # from.

Since that time, I have come to use 65 psi all around on my Globetrotter. This will support 10,160 lbs so I have plenty of margin for my 6,540 weight while towing. I run 65 psi in the rear tires of the TV. I have also made some adjustments to my WD hitch. No more frame separation / popped rivets / or rough ride. I use the EEZ Tire pressure monitoring system and stay within safe psi parameters when towing.

YMMV, but this works for me.

[Mollysdad]

Originally Posted by wulfraat

65lbs on 15” goodyear endurance for my 30’ international. Tire load is ~1,875lbs per tire when hitched / ready for camping.

65lbs is well north of the minimum inflation pressure for that load based on the goodyear specs.

I’m happy with that [emoji4]

I agree with everything you said. Especially the "well north" of the chart.

Originally Posted by Njg

On a slightly related note, has anyone had trouble installing the repeater for the TST inside of the trailer? My OCD side wants to make sure the admittedly nominal battery draw is measured by my Victron battery monitor shunt, which is installed inside..

I installed mine inside the propane cover lid with Velcro.
I ran the power to the Zamp connector on the battery box (reversed).
I called TST and they assured me the repeater drew so little power you could leave it plugged in. But I just pull the connector when not in use.
To be perfectly honest, I'm not sure you need the repeater at all. I've forgotten to plug it in and the transmitters still all checked in.

[Mollysdad]

Originally Posted by ETroup

Here is how I calculated the optimal tire pressure for the Goodyear Endurance tires on our AS International 27FB. Notice I rounded the max trailer weight up to 10,000 lbs.

Even though the sticker on the Airstream suggests 80 lbs., that is simply too hard creating a rough and harmful ride for the trailer.

Normally I run the AS tires at between 60 - 65 lbs and monitor with TMPS.

Rounded up to 10,000 pounds? On a 7600 pound trailer?
And then forgot to subtract tongue weight?
That's using the Goodyear chart to it's ultimate fudge factor!

Not that you're wrong. I agree with 65, I'm trying to make the GY chart valid.
I'm waiting to hear from some one who says, "I used the GoodYear chart and I run my tires at 30 psi."!

[GOUSC]

Quote:
Originally Posted by wulfraat View Post
65lbs on 15” goodyear endurance for my 30’ international. Tire load is ~1,875lbs per tire when hitched / ready for camping.

65lbs is well north of the minimum inflation pressure for that load based on the goodyear specs.

Originally Posted by MollysDad
I’m happy with that
I agree with everything you said. Especially the "well north" of the chart.

Wufraat and I have the same TV and his RV his larger than mine. He gave me some advice regarding this with a PM awhile back. He's been doing this towing thing for awhile. His advice made since to me and fell in line with what I had researched. It solved my issues and I'm fine with the results.

[gypsydad]

Originally Posted by Mollysdad

I agree with everything you said. Especially the "well north" of the chart.

I installed mine inside the propane cover lid with Velcro.
I ran the power to the Zamp connector on the battery box (reversed).
I called TST and they assured me the repeater drew so little power you could leave it plugged in. But I just pull the connector when not in use.
To be perfectly honest, I'm not sure you need the repeater at all. I've forgotten to plug it in and the transmitters still all checked in.

I installed mine on the outside of the A-frame adjacent to the battery box couple years back. No issues.

[LNBright]

My 20' is a single-axle instead of a double-axle, so I'm splitting between two tires, not four. I'm running my Endurance at 72psi cold. 65 would have been enough, but as the previous tires on it had been Marathons at 80psi, and the Endurance is a better tire, I knew I didn't have to keep it at 80; but although 65 should be fine, it just felt like it was too far... I still didn't want to go 'too' low, so I made sure I passed 70, but under 75. Worked well thus far.

[ETroup]

Originally Posted by Mollysdad

Rounded up to 10,000 pounds? On a 7600 pound trailer?
And then forgot to subtract tongue weight?
That's using the Goodyear chart to it's ultimate fudge factor!

Not that you're wrong. I agree with 65, I'm trying to make the GY chart valid.
I'm waiting to hear from some one who says, "I used the GoodYear chart and I run my tires at 30 psi."!

If I did use 7600lbs, subtracted 800 lbs hitch weight, then divided by 4; the 1700 lbs per tire would indicate 50-55 psi per the chart (not 30). So 65 psi seems very safe reasonable compromise while the 80 psi max specification seems unnecessarily hard.

[ETroup]

Originally Posted by ETroup

If I did use 7600lbs, subtracted 800 lbs hitch weight, then divided by 4; the 1700 lbs per tire would indicate 50-55 psi per the chart (not 30). So 65 psi seems very safe reasonable compromise while the 80 psi max specification seems unnecessarily hard.

I recently updated the calculation process to determine optimal safe tire pressure.