Tire Pressure Question

[TCNashville]

I upgraded to an E rated tire from a D rated tire. I enjoy the extra "cushion" of weight rating the E rated tires gives me at 80psi instead of 65psi. I guess I'm old school but running an ST tire below max psi produces more heat and sidewall flex. Comparing an ST tire to an LT tire is apples to oranges and comparing an ST tire to engine rpm is kinda silly. To each his own I guess.

[ShawnR]

Originally Posted by Goldie50

I just bought new Goodyear Endurance tires for my 2015 White Hawk 27DSLR. It has 14” rims and the previous tires and the sticker placed by the factory calls for 50lbs TP. The fine folks at Discount Tire insisted the tires call for Maximum pressure of 65lbs. They pointed out that my previous tires called for 50lbs maximum. Should I go by what is on the sticker?

Use the inflation table published by Goodyear to be sure your tire pressure is sufficient for the load and you’re good to go.
https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

[Atlee]

Originally Posted by bigironcoder

My uncle and I used to argue about this all the time. IMO, it's not a one size fits all thing. As BrentB said above, it all depends on the weight the tires are carrying. Sure, setting tires to the "maximum" pressure would be essential if carrying maximum weight for the tires. But what if your trailer's GVWR is much less than the maximum weight for the tires? Combine that with rough roads, concrete interstates, and my lightweight trailer would spend 1/2 its time airborne. I go by Goodyear's chart and keep my tires at 50 lbs. Rides much better.

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

My trailer's GVWR is 3,750 of which 12% is on the hitch, so that's 3,300 lbs on the tires. I have Goodyear Endurance ST 205 / 75R14, Load Range D, 65 max psi, 2,040 lbs tires, for a tire carrying capacity of 4,080 lbs at 65psi. According to the pointy heads at Goodyear who designed these tires, I can carry 3,520 lbs at 50 psi.

For my understanding, you only air your tires up to 50 psi, giving you 1750# for each tire. You are also saying that your trailer only has 1650# on each tire. Correct? If that is the case you only have a "safety" margin of 110# per tire or 6.6%. Isn't that cutting it a bit thin? And you are assuming that 3300# on the tires is spread exactly 50% on each tire, correct? I seriously doubt that the weight of your trailer is spread exactly 50% on each tire.

I prefer a 20% margin on each tire, if I can get it. If I err, I want to err on the side of over inflating, rather than under inflating. Less danger in over inflating.

[Atlee]

Originally Posted by wags999

Because they list different PSI depending on the weight the tire is carrying, I can see if you have less weight, the tire could be over inflated and hence, not be as "flat" as it should be. Has to be a difference in tire profile with zero weight and max weight on it, I would think.



I upgraded to Goodyears with an E rating, at 80 PSI I can carry 30 + percent more weight than my max trailer rating. I will try 65PSI which still gives me a large cushion over actual weight and see how it handles and tows.

Why did you feel the need to move up to an E rated tire when the D rated tire already gives you a "large cushion over actual weight"?

[Atlee]

Originally Posted by ShawnR

Use the inflation table published by Goodyear to be sure your tire pressure is sufficient for the load and you’re good to go.
https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

Which means, to be totally correct, one needs to know exactly how much weight EACH tire is carrying, and inflate accordingly. I dare say there are only a hand full of folks who actually know how much weight each tire is carrying. I bet it would also surprise you to know how many folks don't even know how much the actual total weight is for their trailer.

In my opinion only, when in doubt, do not under inflate based on assumptions.

[mikegray]

Just looked at my TV tire pressure recommendations on the tires themselves and it calls for 44 psi max and load limit to 2400 lbs. Does that mean I can tow 9600 lbs with those tires? Just talking about the tires not other factors.
Mike

[bigironcoder]

I understand why some choose to keep their tires at the max pressure as stated on the tire. Doing so would take the risk out of blowing a tire due to under-inflation. Nothing wrong with a better be safe than sorry philosophy.

But if someone is having trouble with excessive trailer bounce, then it might be time to take a closer look at weight versus tire pressure. Goodyear's chart, for example.

Another thing I don't think anyone has mentioned is checking tire temperature. I started carrying a remote temperature gun a few years ago. It's amazing how much hotter the tires facing the sun get. I know some TPMS systems trigger a warning at about 155 degrees, so I watch for temps getting up close to 140. It's not unusual to see temps around 130-135 on the sun side and 120 on the other side. Just a thought. Low pressure equals hot tires.

[Johnny Lightning]

Originally Posted by oldmanAZ

Why do you believe that inflating trailer tires to what a tire manufacturer says is the "maximum" is an "urban legend"?
The tire manufacturer shows the maximum pressure on their inflation chart so do you agree that the "maximum" is a safe pressure for someone unsure of what their trailer tire load really is?
For a given load, do you agree that a tire inflated to pressures below what the manufacturer inflation chart shows, it is then, by definition, underinflated?
Do you believe that underinflated tires are unsafe?

I will say this one more time. A properly inflated tire is safe, anything above or below that pressure is less safe. Once again, if the safest pressure was the one written on the sidewall it would say "Inflate to xx lbs." It doesn't, is says "Maximum inflation pressure xx lbs." There is a reason for this. The last thing, if you don't know how much your trailer weighs go to a scale and get it weighed, it ain't so tough. Better yet, get the weight for each wheel and balance the load between them. And in the words of Forest Gump "That's all I have to say about that."

[RAurand]

Ok.

[Murff]

This topic has been discussed on this forum many times.

If you feel you need to put the Maximum pressure stamped on the sidewall, that is your choice.

However, if Goodyear wanted their tires inflated to the maximum pressure, I think their Endurance inflation chart would say that. It doesn't! They make an inflation chart based on the weight of your rig.

I may be old school, but an over inflated tires does not have as much tire surface touching the road and, you may disagree with this, but when I hit my brakes, I want as much tire on the road to stop me as possible.

One more whack at the deceased equine!

Murff

[GHen]

Am i wrong to suggest that hitting a bump or a dip in the road would increase the weight on the tire as the rv goes down and the suspension is compressed?
If so, I think I would want my tires at the suggested maximum to handle those increased loads above scale weight.

[jadatis]

answer to above.
Indeed the weight is getting more( and less ) when hitting a bump, but it does not matter for the needed tire-pressure.
Pressure advice is to give the tire a deflection that wont overheat any part of tire , for the speed driven.
That one cycle the tire deflects more , wont give that much heatproduction , that sertain part of rubber gets over a temp at wich it hardens permanently, so ireverible damage is done.

[spoon059]

Originally Posted by Murff

I may be old school, but an over inflated tires does not have as much tire surface touching the road and, you may disagree with this, but when I hit my brakes, I want as much tire on the road to stop me as possible.

My tires are inflated to 80. I checked my contact patch, I am getting full width contact. My tires also run cool, never more than 20 degrees above ambient. I'm happy with my stopping ability, towing ability and the structural integrity of my tires.

[Murff]

No arguement Spoon059.

As the 2nd sentence in my post stated, "If you feel you need to put the Maximum pressure stamped on the sidewall, that is your choice."

But, keep in mind, that as tires heat up from highway use, the tire pressure also increases. Your "contact patch" may not be as full as you think while rolling down the road.

Murff

[TCNashville]

Originally Posted by Murff

But, keep in mind, that as tires heat up from highway use, the tire pressure also increases. Your "contact patch" may not be as full as you think while rolling down the road.

Murff

Pretty sure this is factored in when tire manufacturers are calculating max psi. IMO, losing full tread contact while having tires inflated to max psi would create an unsafe condition. Again, I doubt the tire manufacturers would do this but I guess you never know.

[Texdan25]

Originally Posted by Goldie50

I just bought new Goodyear Endurance tires for my 2015 White Hawk 27DSLR. It has 14” rims and the previous tires and the sticker placed by the factory calls for 50lbs TP. The fine folks at Discount Tire insisted the tires call for Maximum pressure of 65lbs. They pointed out that my previous tires called for 50lbs maximum. Should I go by what is on the sticker?

So I just got back from my first trip with my new Endurance tires on the same trailer as above. The original Rainier tires were rated at 1760 lbs. Discount Tire had inflated the new ones to 65# which according to the chart would provide a load of 2040#. Traveling in the Texas hill country it seemed a little 'bouncy' but I can't compare it to the originals. Anyhow, wondering if I should drop down to 60# for a load rating of 1950# and what effect that would have (handling, braking, endurance, etc?) Also, if running at max pressure of 65# what happens when towing in the Texas summer heat where the tires most certainly will gain psi?

[Riverman]

I run 60 in my 14" tires.

Check and inflate them when cold. Sure, pressures go up in hot weather or when in use but the tire is designed to handle that.

[spoon059]

Originally Posted by Murff

No arguement Spoon059

........

But, keep in mind, that as tires heat up from highway use, the tire pressure also increases. Your "contact patch" may not be as full as you think while rolling down the road.

Murff

No arguement...? You sure?

Yes, I have tested my contact patch cool and at the end of a long day of towing in warm weather. I'm satisfied with 80 PSI. Thank you.

[jadatis]

In general for TT's tires support yust the gawr,s, and even ST tires for 65mph calculated in maxload, so TT maker can buy cheapest wheels.
If ao the 50 psi is to the edges of safe, a bit higher speed then 65mph, and/or a bit more axleweight icw unequall load R/L, and/or, a bit inacurately to high read pressure or presduredropp in time, and the tire overheats.
If one time overheated long enaugh, the damage is ereversible, and after 3 years mayby blowing tire, with missery that can go with it.
Then the new ( I guess D- load) tire needs the 65 psi to give it some more reserve.

But topic on Airdale forum, made clear thoae have a comfortable reserve, so they could even so for C-load (at 50psi) with lower then 50 psi. Then the D- load can do with probably 55 psi.

In short, give GVWR of TT, 3 things of tires.
1. Maximum load or loadindex
2. Loadrange or better pressure given behind AT on sidewall.
3. Speedcode and if ST or LT ( or P-tire in SL or XL)

Then I will calculate with my extra safe calculator, so will sertainly not give to low pressures.
Better would be to weigh the TT fully loaded.

[AKGperson]

I've always gone by what the tire manufacturer recommends, not what the vehicle manufacturer recommends. If Goodyear recommends 65psi, run them at 65psi.