Endurance Tire pressure on 27FB Int'l

[ROBERT CROSS]

Originally Posted by alphamale49

Does anyone ever rotate the tires on their Airstream?

Yes...every Spring.
It's a habit I acquired as a result of tire removal for Winter storage. It helps the tires and the underrated AS axles.👍

Bob
🇺🇸

[StuartsDad]

We have GYE`s on our 28`. Ran 1st season at 80 psi because dealer swore it had to be. Brutal for trailer and us. Based on forum input and Goodyear chart, I picked a happy medium of 55psi cold. Pulled 625 miles in last two days, much better and may go a little lower yet.

[overlander63]

Originally Posted by alphamale49

Does anyone ever rotate the tires on their Airstream?

Yes.
Rotate front-to-back only, to minimize the possibility of belt separation from reversing rotation.

[delrossa]

I installed the Goodyear Endurance tires a few thousand miles ago. We have a 28’ Flying Cloud and the prior Marathons were run at 65 psi. I run the Endurance’s at the same 65 psi. I have tire monitors and the temps and pressure increases are the same as the Marathons. The tire wear is even on all 4.
I didn’t increase the tire pressures as I was concerned with the ride harshness.

[ROBERT CROSS]

I seem to recall an expert admonition..."lowering IPS to improve ride is not always the best option"🤔

Bob
🇺🇸

[gypsydad]

Originally Posted by delrossa

I installed the Goodyear Endurance tires a few thousand miles ago. We have a 28’ Flying Cloud and the prior Marathons were run at 65 psi. I run the Endurance’s at the same 65 psi. I have tire monitors and the temps and pressure increases are the same as the Marathons. The tire wear is even on all 4.
I didn’t increase the tire pressures as I was concerned with the ride harshness.

Suggest you weigh your AS and adjust tires to recommended GY Endurance chart mentioned here...my 28' weight according to the GY Endurance chart says 45psi... I run between 45 and 50 and monitor with the TPMS. No more issues with cabinet door hinges or popped rivets...which I experienced when the tires were installed new last summer and dealer had them filled at 70PSI...the chart PSI for the given weight for these tires seems to be the best reference.; I would guess your 28 is no different after you get to the scales....45-50 PSI should be right.

[jadatis]

I extpected for Airstreams the tires also been yust enaugh for the GVWR .
But remarks about bumping here, made me think they have a comfortable reserve.

So I searched back pictures I made ,when camping in Austria in Petneu, from a tandem-axle Airstream, and calculated pressure with my made extra safe calculator.

GVWR 7300 lbs, and even overrated axles of 3800lbs GAWR
Tires ST225/75R15 prescribed 65 psi.
Maxload acording to given list here 2540lbs wich is loadindex 113.
Gave with GVWR and 10% on pin , 46 psi .
Lowered the loadindex by 6 to give max pressure without bumping and gave 55 psi.

So the Airstreams are exeption to the rule in TT world, and are given tires with a comfortable reserve. The 65 psi advice then must give bumping, if not overloaded.

[ROBERT CROSS]

Originally Posted by jadatis

I extpected for Airstreams the tires also been yust enaugh for the GVWR .
But remarks about bumping here, made me think they have a comfortable reserve.

So I searched back pictures I made ,when camping in Austria in Petneu, from a tandem-axle Airstream, and calculated pressure with my made extra safe calculator.

GVWR 7300 lbs, and even overrated axles of 3800lbs GAWR
Tires ST225/75R15 prescribed 65 psi.
Maxload acording to given list here 2540lbs wich is loadindex 113.
Gave with GVWR and 10% on pin , 46 psi .
Lowered the loadindex by 6 to give max pressure without bumping and gave 55 psi.

So the Airstreams are exeption to the rule in TT world, and are given tires with a comfortable reserve. The 65 psi advice then must give bumping, if not overloaded.

I'm happy for you, AS has improved payload and axle ratings over the years...it has not always been so.👎

My food and adult beverages can consume half of my CCC, and I refuse to leave the Wife & Dog behind.

I will run my psi accordingly.

Bob
🇺🇸

[CapriRacer]

Originally Posted by overlander63

Yes.
Rotate front-to-back only, to minimize the possibility of belt separation from reversing rotation.

Just so everyone knows, this is obsolete advice. Things have changed and the reason why this advice was offered has be fixed. If you want the technical details and the history, I can do that. Warning: It's a long and boring story.

[jadatis]

Originally Posted by wulfraat

Goodyear published their load chart and speed rating for the new endurance tire. I have attached above.

Airstream use the 225/75R15 size endurance tire on 25'+ trailers.

The Endurance tire is speed rated to 87mph (not 65mph) based on the minimum inflation PSI, which is in turn based on the load on the tire. That is what Goodyear publish for this tire (no mystery on tire specs here .

If you want to know what minimum PSI your specific trailer needs to adhere manufacture specifications, just run your trailer over the cat scale, calculate your tire load (per tire), and look up the minimum inflation requirement in the table based on the tire size.

If you want to go with a higher PSI than what is in the load chart there is no harm in doing so, you simply yield a firmer than necessary ride.

The max speed of Endurance is indeed 140kmph/87mph, but most ST tires , and also the Endurance most, are given maxload for 65mph.
In earlyer days the old ST , for max speed 75mph the 65ps for D-load had to be highened up with 10 psi to 75 psi, and for 85?mph and 10 psi higher, and 10% reduction of maxload.
Mayby Capri Racer wants to comfirm this.
I realise that you wont take it from this amateur european guy, that put gremlins in your tire.

In the list you linked to , there is 235/85 R 16 G-load ( AT 110 psi) , both in ST and LT.
Only difference in construction could be lesser profile for the ST.
Maxload ST 4400LBS is loadindex 132.
Maxload LT 3750 LBS IS LI 126.
Most LT are calculated in maxload for 160km/99m/h, and the system I figured out the tiremakers also use is rule of tumb 1 LI-step different for every 10km/6.5m/h different.
Higher speed 》lower LI, lower speed 》 higher LI.
The 6 LI- step higher for ST here, is almost in line with the 6x6.5mph lower is 39 mph lower speed would be 60mph , so this proves the higher maxload for 65mph for wich the ST is calculated.

[gypsydad]

Originally Posted by jadatis

The max speed of Endurance is indeed 140kmph/87mph, but most ST tires , and also the Endurance most, are given maxload for 65mph.
In earlyer days the old ST , for max speed 75mph the 65ps for D-load had to be highened up with 10 psi to 75 psi, and for 85?mph and 10 psi higher, and 10% reduction of maxload.
Mayby Capri Racer wants to comfirm this.
I realise that you wont take it from this amateur european guy, that put gremlins in your tire.

In the list you linked to , there is 235/85 R 16 G-load ( AT 110 psi) , both in ST and LT.
Only difference in construction could be lesser profile for the ST.
Maxload ST 4400LBS is loadindex 132.
Maxload LT 3750 LBS IS LI 126.
Most LT are calculated in maxload for 160km/99m/h, and the system I figured out the tiremakers also use is rule of tumb 1 LI-step different for every 10km/6.5m/h different.
Higher speed 》lower LI, lower speed 》 higher LI.
The 6 LI- step higher for ST here, is almost in line with the 6x6.5mph lower is 39 mph lower speed would be 60mph , so this proves the higher maxload for 65mph for wich the ST is calculated.

https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

The GY Endurance chart above shows recommended weight and PSI per tier, with max speed of 87mph for 15" tires...Again, take your trailer weight and divide by 4 to get your "pretty close" to actual weight on each wheel/tire for easy calculation. Or you can always weigh each wheel if you want to be totally accurate...

Tire Size MAX-MPH Inflation PSI
45psi 50psi 55psi 60psi
ST225/75R15 87mph 2020 2150 2270 2380

[ROBERT CROSS]

Originally Posted by jadatis

The max speed of Endurance is indeed 140kmph/87mph, but most ST tires , and also the Endurance most, are given maxload for 65mph.
In earlyer days the old ST , for max speed 75mph the 65ps for D-load had to be highened up with 10 psi to 75 psi, and for 85?mph and 10 psi higher, and 10% reduction of maxload.
Mayby Capri Racer wants to comfirm this.
I realise that you wont take it from this amateur european guy, that put gremlins in your tire.

In the list you linked to , there is 235/85 R 16 G-load ( AT 110 psi) , both in ST and LT.
Only difference in construction could be lesser profile for the ST.
Maxload ST 4400LBS is loadindex 132.
Maxload LT 3750 LBS IS LI 126.
Most LT are calculated in maxload for 160km/99m/h, and the system I figured out the tiremakers also use is rule of tumb 1 LI-step different for every 10km/6.5m/h different.
Higher speed 》lower LI, lower speed 》 higher LI.
The 6 LI- step higher for ST here, is almost in line with the 6x6.5mph lower is 39 mph lower speed would be 60mph , so this proves the higher maxload for 65mph for wich the ST is calculated.

Jypsydad,
The chart is way to easy.

We are using 'rule of thumb' calculations here, without knowing the size of the thumbs. 🤓

Bob
🇺🇸

[CruizinDux]

This is from my earlier post of a great discussion re: gye - psi - load per tire -margin - speed rating 65 vs 87...discussion initially revolving around the fact (as i understand them...TM9 & CR, please correct if i' missed it) ST tires and 65 mph speed rating.

Took me awhile to find it buy here ya go...

http://www.airforums.com/forums/f438...157249-16.html

Post #220 by capri racer and #223 by tireman9

TM9 & CF, thanks again for your sound advice. I have found it good to reread on occasion. This trip my laptop crashed so my handy reread link was not so handy.
B

[jadatis]

Giving maximum load for lower speed then the max acording to speedcode, is commonly used by the tiremakers for P-tires. So its not a flat earth theory of mine and CruzinDux gave the link to the prove of using 65mph for ST in former post.
Most P-tires give maximum load for 160kmh/99mph , this is the reference speed.
Then for P-tires they use a system of highening up the reference-pressure of SL 35 or 36 psi and XL 41 or 42 psi, for higher speed.
They give the maximum allowed cold pressure only on P-tires of between 44 and 51 psi, and for XL sometimes even 60 psi.
The space between reference and maxcold is used for that highening up reference ( LT pressure behind AT) for speed and camber angle ( alignment tires like this on the axle /-\ instead of this|-|) above 2 degr.
This system and the European Formula I once got hold of and went running with.
Alternative system for this could also be lowering the maximum load for speed.A simpler system and to my conclusions saver and more to the rules of nature.
Will give a image I made with the needed pressure rising for speed .
For V-W-Y speedrating 30 kmph below maxspeed even maxload is lowered, yust the same as for the LT tires system.

[OTRA15]

Originally Posted by CruizinDux

One of many gye threads with great psi/tire load comments by tireman9 and capri racer.

http://www.airforums.com/forums/f438...-157249-9.html

Bingo!

An alternate link which should lead to the start of that thread:

http://www.airforums.com/forums/f438...sa-157249.html

Bob's more recent comment:

Originally Posted by CruizinDux

This is from my earlier post of a great discussion re: gye - psi - load per tire -margin - speed rating 65 vs 87...discussion initially revolving around the fact (as i understand them...TM9 & CR, please correct if i' missed it) ST tires and 65 mph speed rating.

Took me awhile to find it buy here ya go...

http://www.airforums.com/forums/f438...157249-16.html

Post #220 by capri racer and #223 by tireman9

TM9 & CF, thanks again for your sound advice. I have found it good to reread on occasion. This trip my laptop crashed so my handy reread link was not so handy.
B

Here is the start of Post #220 in that thread -- click on orange arrow in quote to go there directly -- and read the rest of the following long post, and the nearby Post #223:

Originally Posted by CapriRacer

. . .
The place to start is with the load tables and the ACTUAL load on each tire. That means if you haven't weighed each individual tire, then you're just guessing.
. . .

The discussion in that earlier thread is worth a good read IMO. Thanks Bob for pointing back there. Way easier to read previous discussions than to repeat them all here again IMO. How many dozens of tire threads are there?



Peter

PS -- Comments are still open in that other thread, so by Quoting Tireman9 or CapriRacer there, intelligent follow-up questions can be resolved in the context of the original comments.


FYI/FWIW

[CapriRacer]

2 thoughts:

1) The load tables are MINIMUMS!! If you are using those, don't forget to use MORE - and my rule of thumb is to have 15% reserve (unused) capacity.

2) If you haven't weighed each wheel position of the vehicle, you are guessing what the actual load on the tire is. We have lots of evidence that load is NOT even, front to rear and side to side.

For example, I use a 15% variation for a 4 wheeled trailer, even though I haven't seen more than 10% from actual weighings.

[MandDinSpgTX]

Originally Posted by out of sight

My new 28 has a tire and load sticker. It calls for 80 PSI.

We have 20,000+ miles now on my 2018 27FC/FB (purchased in mid-2007) and have the Goodyear Endurance E. When I spoke with the Goodyear folks direct, it was clear the stamp on the tire says 80lbs per tire (cold). We also have TPMS and believe it or not have never had the tire pressure vary more than 2 lbs (max) in almost 2 years now of driving. And yes, that is through the summers in Oklahoma and Texas (Houston, here) and to the extreme winters in Cleveland, Ohio. Consistent. In fact, they told me that the tires are designed to perform optimally at that pressure. Mine actually show no signs of wear either (just had them inspected since we are pretty anal about replacing tires even on our vehicles). Coupled with the Hensley Hitch (hydraulic strut version set on middle position) and the Hensley brake controller and we haven't even had so much as a slide on the road or any pressure issues whatsoever. We will keep watching it, but so far it has been effortless. Hope this helps.

[MandDinSpgTX]

Originally Posted by MandDinSpgTX

We have 20,000+ miles now on my 2018 27FC/FB (purchased in mid-2007) and have the Goodyear Endurance E. When I spoke with the Goodyear folks direct, it was clear the stamp on the tire says 80lbs per tire (cold). We also have TPMS and believe it or not have never had the tire pressure vary more than 2 lbs (max) in almost 2 years now of driving. And yes, that is through the summers in Oklahoma and Texas (Houston, here) and to the extreme winters in Cleveland, Ohio. Consistent. In fact, they told me that the tires are designed to perform optimally at that pressure. Mine actually show no signs of wear either (just had them inspected since we are pretty anal about replacing tires even on our vehicles). Coupled with the Hensley Hitch (hydraulic strut version set on middle position) and the Hensley brake controller and we haven't even had so much as a slide on the road or any pressure issues whatsoever. We will keep watching it, but so far it has been effortless. Hope this helps.

Sorry, should have read "purchased in 2017......" Sorry for the typo, before the flames start flying.......

[brick1]

Originally Posted by out of sight

My new 28 has a tire and load sticker. It calls for 80 PSI.

My 2018 Serenity 28 also has factory stickers calling for 80 psi cold. I am following the factory recommendations, as I hope the factory knows what they are doing.

[wulfraat]

Originally Posted by CapriRacer

2 thoughts:

1) The load tables are MINIMUMS!! If you are using those, don't forget to use MORE - and my rule of thumb is to have 15% reserve (unused) capacity.

2) If you haven't weighed each wheel position of the vehicle, you are guessing what the actual load on the tire is. We have lots of evidence that load is NOT even, front to rear and side to side.

For example, I use a 15% variation for a 4 wheeled trailer, even though I haven't seen more than 10% from actual weighings.

Agreed. By the table and per CAT scale fully loaded ready for camping, I should be at 40 PSI minimum strictly speaking (1,880lbs/tire). Due to front-to-rear & side-to-side load differences, and additional overhead factored in, I run at 65 (2,540lbs/tire). 35% reserve / buffer.