Endurance Tire pressure on 27FB Int'l

[JohnTF]

The number 1 reason tires fail - overheating .
The number 1 reason tires overheat - is low air pressure .
Numbers on car , truck , trailer for load - stick with those numbers & match then to the tires .
Number on tires need to match the load & air pressure

[Tireman9]

Originally Posted by LAWBC

Just replaced original tires on my 27 FB International and set pressure at 70 PSI . I have read where some run lower pressure, my Marathons where 65 PSI and never had a problem with them for 6 years.
The installer tells me that the Endurance are 10 ply where the Marathons where only 6ply.
What tire pressure at cold do you set yours ?

"Ply Rating" is an old term from the 60's & 70's. You can read the sidewall of your tires and find both the number (many times one) and the material (Polyester) in the tire sidewall.
l "Load Range" is the current term for the tire's ability to contain the inflation pressure with Load Range "E" being the replaceemntfor the old 10 ply rating.


Your installer apparently has not bothered to keep up his/her education and knowledge of tires. You might consider finding a more knowledgable tire dealer.

[AlbertF]

Originally Posted by jadatis

To AlbertF: did you add 10% for reserve first before looking in the list.
This is to cover unequall load R/L wich is always the case for TT's.

Oh no , in America minimum 10% on pin, and so axle load is 90% of GVWR.
Adding 10% to that 90% gives 99% , is about 100% , so looking back GVWR is also good.
But looking in my made lists , you get about 5psi more so 60psi I estimate will be the advice then.

My goal is to give the tire a minimum deflection, so maximum pressure, at wich gripp is still acceptable and no bumping.
Then if pressure drops in time, or inacurately to high measured, you still ride with save pressure.

The 22fb has an empty tongue weight of 422 lbs. Water tank, water heater and most storage are ahead of the axle, so loaded tongue weight will be over 600 lbs. With WDH about 450 to 500 lbs will be on the tow vehicle. Typical load per tire should be just over 2000 lbs with trailer at GVWR. 55 psi gives 2270 lbs capacity - a bit more than 10% margin.

[LAWBC]

Scaled

Scaled my trailer hitched with full gas tanks and full fresh water is 6130 lbs ready to camp not including the tongue weight


Based on GYE chart with adding a 30 % margin for load shifting flex, my trailer is near 8000 lbs that would make it 2000 LBS per tire= @ 45 PSI

[ROBERT CROSS]

Originally Posted by LAWBC

Scaled

Scaled my trailer hitched with full gas tanks and full fresh water is 6130 lbs ready to camp not including the tongue weight


Based on GYE chart with adding a 30 % margin for load shifting flex, my trailer is near 8000 lbs that would make it 2000 LBS per tire= @ 45 PSI

What size tire?

Bob
🇺🇸

[Timcarr]

I have never seen a tire that did not have the pressure rating embossed on the side of the tire. All you have to do is read what it tells you and inflate to that pressure.

[ROBERT CROSS]

Tim,
The first thing you will learn here on the Forums...Airstreaming is far more complicated than it appears on the sidewall.

Sweet Streams...
Disclaimer...I do use the sidewall pressure, with slight adjustments from the chart I keep in my head.

Bob
🇺🇸

[jadatis]

Originally Posted by LAWBC

Scaled

Scaled my trailer hitched with full gas tanks and full fresh water is 6130 lbs ready to camp not including the tongue weight


Based on GYE chart with adding a 30 % margin for load shifting flex, my trailer is near 8000 lbs that would make it 2000 LBS per tire= @ 45 PSI

Welcom back, take it that you read it all.
Conclusion I took was that AS are exeption to the rule, and have a comfortable reserve in maxload of tires. But sill they give general advice of refence-pressure for TT.
Saw 2020 lbs at 45 psi for ST 225/75R15, so this must be your sise.
Trew it trough my made extra safe calculator, and used the exagerated 30% reserve
D- LOAD ( AT65psi ) gives 50 psi and your new E- load( AT80psi) gave 55 psi.
Also lowered the loadindex by 6 to find max pressure without bumping ( but 30% reserve then bumping) and it still came to D 60psi and E 65 psi.
So higher is absolutely not needed.

[ROBERT CROSS]

Sidewalls, charts, safe calculator's...whew.🥴

A simpler rule to follow...if your tires are under inflated, fill them 'til they aren't. 😂

Bob
🇺🇸

[SteveSueMac]

Originally Posted by ROBERT CROSS

Sidewalls, charts, safe calculator's...whew.🥴



A simpler rule to follow...if your tires are under inflated, fill them 'til they aren't. [emoji23]



Bob

[emoji631]

You need to write a book - “Advice I Have Given” [emoji23]

I’d so buy it! [emoji3]

[sctinman44]

Originally Posted by wulfraat

I run my endurance at 65 on my 30’ ... it weighs in at about 7,000 lbs across both axles hitched and ready for camping.

Here is the load chart for the endurance....

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

Technically @1,750lbs load per tire (hitched) 40lbs is acceptable assuming the front axle has 10% more load due to the trailers overall weight distribution. These tires are speed rated to 87mph.

I may drop down to 50-55;this season to improve ride quality whilst still being far north of minimum inflation requirement.

I run 65 psi on my 1998. 31ft Classic. Trailer weighs 8,800 lbs consistently. LRE rated 2540 per × 4 = 10,160. Might drop to 60 psi @ 2380×4= 9520 and monitor it closely. Would give softer ride. I do not exceed 65 mph towing, my sweet spot for fuel economy is 62 mph and 16 mpg towing. 2015 Ram 1500 Ecodiesel .

[gypsydad]

Originally Posted by sctinman44

I run 65 psi on my 1998. 31ft Classic. Trailer weighs 8,800 lbs consistently. LRE rated 2540 per × 4 = 10,160. Might drop to 60 psi @ 2380×4= 9520 and monitor it closely. Would give softer ride. I do not exceed 65 mph towing, my sweet spot for fuel economy is 62 mph and 16 mpg towing. 2015 Ram 1500 Ecodiesel .

This gets really difficult to follow when I see a statement like this. You have not said which brand tires nor size. Nor, what the Mfg. of the tire's recommends for your weight. But, Your not the only one in these threads that omits the brand tire and tire chart information for given weight. Likely you have 16" tires on that Classic? Just guessing...but which brand?? Michelins are different than GY Endurance as an example...

[sctinman44]

Originally Posted by gypsydad

This gets really difficult to follow when I see a statement like this. You have not said which brand tires nor size. Nor, what the Mfg. of the tire's recommends for your weight. But, Your not the only one in these threads that omits the brand tire and tire chart information for given weight. Likely you have 16" tires on that Classic? Just guessing...but which brand?? Michelins are different than GY Endurance as an example...

INFO from my MAXXIS spec chart: ST225/75R15 LRE. PSI---65psi--2540x4=10,160 lbs. Psi- 60psi-2380×4=9,520. Max speed 65 mph. 1998 Classic 31ft trailer 8,800 lbs consistently. I think/assume the DOT specs are pretty much the same, per, size tire with respect to psi and weight carried. Only difference I see is "MOST" all ST tire spec 65 mph speed where as the new GYE specs 87 mph. Who on earth would tow a trailer 87 mph. That's insane. 😂😂😂

[sctinman44]

BTW I upgraded from 20 year old 4000 lb axles to 5000 lb axles so the DW can carry many more shoes and buy more antiques, etc to haul from the west coast back to SC. My loaded gvw went from 8300 to 10300. So trailer and tire are not over loaded.

[CapriRacer]

I want to clear up a bit of confusion.

It doesn't matter what brand of tire, the load tables are the same (or very close) and any differences have to do with which tire standardizing organization the particular tire is built to - and that is not consistent within a brand.

It's very easy to see when comparing ST tires because there is only one tire standardizing organization - TRA (Tire and Rim Association, based in the US) Compare Maxxis to Goodyear. (Taiwanese vs US)

Further, ALL load tables are MINIMUM's - not recommendations. (or maximum's if you approach from the other direction.) You need to use MORE pressure than what the tables says. I recommend 15% more load carrying capacity (which is what car and SUV manufacturers do.)

Every trailer ought to have a sticker (commonly called the vehicle tire placard) that lists the original tire size and the specified pressure for that size. If I remember correctly, since 2008 it is supposed to be towards the front of the trailer. It is supposed to be a yellow sticker just like your car, SUV or truck - and those are supposed to be on the driver's doorframe.

Prior to 2008, the location of the placard wasn't specified and on cars, SUV's, and trucks, it could be found on the driver's door frame, or some other door frame, in the glove box, on the fuel filler door, on the underside of the trunk lid - and in the case of travel trailers, on the entry door. It was white, not yellow, and it's format varied a bit.

[gypsydad]

Originally Posted by sctinman44

INFO from my MAXXIS spec chart: ST225/75R15 LRE. PSI---65psi--2540x4=10,160 lbs. Psi- 60psi-2380×4=9,520. Max speed 65 mph. 1998 Classic 31ft trailer 8,800 lbs consistently. I think/assume the DOT specs are pretty much the same, per, size tire with respect to psi and weight carried. Only difference I see is "MOST" all ST tire spec 65 mph speed where as the new GYE specs 87 mph. Who on earth would tow a trailer 87 mph. That's insane. ������

Thanks for the clarification; I had poor luck on my Casita with Maxxis several years ago..1 blow out and the other bubble which I caught while on a trip. That was 18 years ago, however.

To answer your question about towing speed, only people driving 87 with an AS are those wanting to pass someone who can only go 65 with their Maxxis! (just kidding of course!)

[gypsydad]

Originally Posted by CapriRacer

I want to clear up a bit of confusion.

It doesn't matter what brand of tire, the load tables are the same (or very close) and any differences have to do with which tire standardizing organization the particular tire is built to - and that is not consistent within a brand.

It's very easy to see when comparing ST tires because there is only one tire standardizing organization - TRA (Tire and Rim Association, based in the US) Compare Maxxis to Goodyear. (Taiwanese vs US)

Further, ALL load tables are MINIMUM's - not recommendations. (or maximum's if you approach from the other direction.) You need to use MORE pressure than what the tables says. I recommend 15% more load carrying capacity (which is what car and SUV manufacturers do.)

Every trailer ought to have a sticker (commonly called the vehicle tire placard) that lists the original tire size and the specified pressure for that size. If I remember correctly, since 2008 it is supposed to be towards the front of the trailer. It is supposed to be a yellow sticker just like your car, SUV or truck - and those are supposed to be on the driver's doorframe.

Prior to 2008, the location of the placard wasn't specified and on cars, SUV's, and trucks, it could be found on the driver's door frame, or some other door frame, in the glove box, on the fuel filler door, on the underside of the trunk lid - and in the case of travel trailers, on the entry door. It was white, not yellow, and it's format varied a bit.

Capri Racer- I think you should talk with the Goodyear factory experts about your assertion of not following their charts for a particular tire, like the Endurance model. Not meaning to be disrespectful but why would you recommend we should be using more pressure than the "Maximum Pressure" recommendations by the manufacturer? Goodyear said the composition used in today's tires differs from Mfg. to Mfg. and tire type; said the "stickers" are there to help folks who don't know their vehicle weight as a safety guide. Maximum performance of given tire to weight is listed in their charts. Sounds like the best advise is to follow their charts??

[SteveSueMac]

Originally Posted by gypsydad

Capri Racer- I think you should talk with the Goodyear factory experts about your assertion of not following their charts for a particular tire, like the Endurance model. Not meaning to be disrespectful but why would you recommend we should be using more pressure than the "Maximum Pressure" recommendations by the manufacturer? Goodyear said the composition used in today's tires differs from Mfg. to Mfg. and tire type; said the "stickers" are there to help folks who don't know their vehicle weight as a safety guide. Maximum performance of given tire to weight is listed in their charts. Sounds like the best advise is to follow their charts??

I’m not Capri - he is a tire engineer...

I went back and read your #42 here - no where in your discussion w/GY does it seem like they said to interpret the load charts as the MAX pressure to carry that specific load. I think you may be interpreting the chart that way and if so, I think you may be mistaken.

What I understand Capri to be saying (and how I’ve understood the charts) is that the PSI number is the MINIMUM pressure required to carry that load. All the tire engineers who participate in these forums talk about individual weight differences in (for a 2 axle trailer) 4 tires which you wouldn’t see from a CAT scale and right out of the gate they recommend usually a 15% cushion to be safe (meaning - if your trailer saw 4000# on your two axles - you’d have an average of 1000# per tire and would add a 15% Safety margin for a total of 1150#/tire to then select a PSI from the load chart).

Whatever PSI is shown in the load table for 1000# is the MINIMUM amount of PSI required to carry that load, not the MAXIMUM.

Glad to be corrected if I have any of this incorrect - including my inference of how you’re reading the load chart.

[gypsydad]

Originally Posted by SteveSueMac

I’m not Capri - he is a tire engineer...

I went back and read your #42 here - no where in your discussion w/GY does it seem like they said to interpret the load charts as the MAX pressure to carry that specific load. I think you may be interpreting the chart that way and if so, I think you may be mistaken.

What I understand Capri to be saying (and how I’ve understood the charts) is that the PSI number is the MINIMUM pressure required to carry that load. All the tire engineers who participate in these forums talk about individual weight differences in (for a 2 axle trailer) 4 tires which you wouldn’t see from a CAT scale and right out of the gate they recommend usually a 15% cushion to be safe (meaning - if your trailer saw 4000# on your two axles - you’d have an average of 1000# per tire and would add a 15% Safety margin for a total of 1150#/tire to then select a PSI from the load chart).

Whatever PSI is shown in the load table for 1000# is the MINIMUM amount of PSI required to carry that load, not the MAXIMUM.

Glad to be corrected if I have any of this incorrect - including my inference of how you’re reading the load chart.

Thanks for that. No disrespect intended for Capri. My interpretation from my discussions with GY was the PSI numbers posted for given load were minimum; not maximum. Sorry if I confused anyone. Not sure where the "+15%" advice is listed anywhere by the Mfg I could find? But, likely not a big deal.

My point is, each tire Mfg. has a "recommended" chart for their tires; why not use that if you know your trailer weight for best performance?? My experience was Discount Tire who installed my replacment GYE's last summer, put in 70PSI; might be ok if my AS weighed in at 10,488lbs! But it was to much air for my 28', which weighs 7,580lbs. When the tires were too stiff, it caused popped rivets, hinge issues, and other issues inside- like cloths closet above foot of my twin bed with TV coming loose, closet door coming off in hall, and also shower door coming loose and hanging down; all this after I put on the new tires...in just a few trips!

I adjusted tire pressure down to between 45-50PSI per the chart after discussions with GY and also discussions on the Forum last year and have had no issues since after towing from MT to TX and several trips since.
As always, your mileage may vary, as may your opinion.

[ROBERT CROSS]

80psi-15%+2psi=70psi. 🤔

Bob
🇺🇸