Tire pressures

[prstlk]

This has probably been asked before but because we are leaving in the AM for the summer I need quick advise from the folks on here.

We have a 2013 Ford F350 SRW 6.7L Diesel and a new to us 2016 Keystone Cougar 30' fifth wheel.

We just put on 4 new Goodyear Endurance tires on the 5th wheel. The tire says to run at 80psi and that is what the tire company put in them.

The label on the 5th wheel says to run 65psi in the tires.

Which should we follow? One of us says the label recommendation and the other says the tire recommendation.

What say you? Please advise!

[Cummins12V98]

"Your best bet is to go with the tire manufacturer’s tire load inflation chart."

"Chicken Dinner"

[valhalla360]

nickthehunter wrote:
The label on the 5th wheel also likely has a tire size and type on it also. If the tires you put on don’t match the label, then the pressure listed on the label is irrelevant. Your best bet is to go with the tire manufacturer’s tire load inflation chart.

That's my guess for why there is a discrepancy between sidewall and trailer sticker.

Keep them all the same PSI but anywhere from 65 to 80 is probably fine. I would lean toward the upper end so long as you don't see it beating up the trailer as you go down the road.

[Cummins12V98]

laknox wrote:

prstlk wrote:
This has probably been asked before but because we are leaving in the AM for the summer I need quick advise from the folks on here.

We have a 2013 Ford F350 SRW 6.7L Diesel and a new to us 2016 Keystone Cougar 30' fifth wheel.

We just put on 4 new Goodyear Endurance tires on the 5th wheel. The tire says to run at 80psi and that is what the tire company put in them.

The label on the 5th wheel says to run 65psi in the tires.

Which should we follow? One of us says the label recommendation and the other says the tire recommendation.

What say you? Please advise!

Your rig is almost certainly placarded for D-range tires, which are 65 psi. Your new GYs are E-rated, which is why the sidewalls say 80 psi. Personally, I'd run the GYs at 70, since you're "over-tired" for the weight of your FW. Will ride a bit better and you'll have a bit more "footprint" on the road. Even then, if you check a load chart, you'll have more tire capacity than the D's at 65 psi.

Lyle

The "E" at 65 is the same as the "D" at 65. BUT with a more solid tire. My boat trailer came with 50psi "C" tires and I run my ENDURANCE tires at 50psi. G

Good thing I did have the extra capacity as I had a total bearing failure and removed the bad tire/wheel and aired the other tire to 70psi. Drove 50 miles at 50 mph or less stopping twice to check tire temp and it did not exceed 117 on a 70 degree day.

[laknox]

prstlk wrote:
This has probably been asked before but because we are leaving in the AM for the summer I need quick advise from the folks on here.

We have a 2013 Ford F350 SRW 6.7L Diesel and a new to us 2016 Keystone Cougar 30' fifth wheel.

We just put on 4 new Goodyear Endurance tires on the 5th wheel. The tire says to run at 80psi and that is what the tire company put in them.

The label on the 5th wheel says to run 65psi in the tires.

Which should we follow? One of us says the label recommendation and the other says the tire recommendation.

What say you? Please advise!

Your rig is almost certainly placarded for D-range tires, which are 65 psi. Your new GYs are E-rated, which is why the sidewalls say 80 psi. Personally, I'd run the GYs at 70, since you're "over-tired" for the weight of your FW. Will ride a bit better and you'll have a bit more "footprint" on the road. Even then, if you check a load chart, you'll have more tire capacity than the D's at 65 psi.

Lyle

[Cummins12V98]

Load/inflation charts are there for a REASON !!!!!!!

Know your weights and follow plus 5psi. It's VERY simple. Lower psi is JUST FINE if you know your weights.

[JIMNLIN]

We just put on 4 new Goodyear Endurance tires on the 5th wheel. The tire says to run at 80psi and that is what the tire company put in them.

The label on the 5th wheel says to run 65psi in the tires.

Which should we follow? One of us says the label recommendation and the other says the tire recommendation.

What say you? Please advise!

Goodyear tire knows about tires on trailers and offer best advice .
Special Considerations
***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.***

Most likely the 65 psi on the tire placard was for a OEM load D tire (65 psi). Unlike tire placards on a truck...most modern trailer tire placards recommend max sidewall pressures for the OEM tire size and load range on the placard.
Tires on a trailer operate in a much more severe service (side scrubbing) on every turn as Goodyear mentions.

Sounds like the Endurance are a tire uprate to a load E at 80 psi. I would run them at 80 psi but watch the center on the tread for wearing faster (over inflation issue).
When a trailer is over tired you can run a chalk line test. Run a chalk line across the tread...then drive in a straight line till the chalk line starts to wear off. You want the same wear across the entire tread for best long term wear/service life/braking on wet pavement/etc.

[MFL]

So...OP was leaving this morning. Unless he left quite early, the answers he got here, would still leave him wondering. I will guess he left them at pressure tire shop used, when they installed. If he would have used the same rated tire, as per his trailer placard, 65 psi is indicated as needed inflation for his trailer.

What CapriRacer posted makes sense to many of us, but may have confused the OP even more??

At least he is leaving with new, quality tires. There is good info out there for him to research, concerning ST trailer tires. A former member here, Roger Marble has a dedicated RV tire blog that he could gain knowledge from.

Jerry

[Michelle_S]

Word of caution: If you run too low of a pressure you run the risk of rolling the tire right off the rim when in a tight turn.
I agree OEMs were probably "D" rated and now you have "E" rated, thus the pressure difference.

[Cummins12V98]

The tires does NOT say to run 80psi!!!!!!! It says for MAX load air to 80psi. Unless you are overloading your axles 65psi will be JUST FINE!!!

Good call on the ENDURANCE!

Weight your rig and use the weight/inflation chart then add 5psi to that number. PER GY Tech Support when going up in load range.

[opnspaces]

50 PSI is max cold for a C rated ST tire
65 PSI is max cold for a D rated ST tire
80 PSI is max cold for a E rated ST tire

Your trailer probably originally had D rated tires hence the 65 PSI label. I always run my trailers tires at max cold.

[nickthehunter]

The label on the 5th wheel also likely has a tire size and type on it also. If the tires you put on don’t match the label, then the pressure listed on the label is irrelevant. Your best bet is to go with the tire manufacturer’s tire load inflation chart.

[KD4UPL]

Your tires do not say "run at 80 psi." They likely say that 80 psi is the maximum cold tire pressure. You can run them at any pressure you like up to 80 but don't exceed 80 cold.
Your trailer manufacturer must have known the weight of the trailer and how much pressure the tires would need to support that weight and thus they have the 65 psi sticker.
To know anything for sure you would need to weigh the trailer, look up the tire inflation tables, and see how much inflation pressure is necessary for that weight. I suspect if you do that it will be around 65 psi, not 80 psi.
You can run 80 if you want but it will result in a harsher, more bouncy ride for the trailer.

[MFL]

fj12ryder wrote:
Without knowing what your weight is, I would go for 80 psi. There are inflation pressure tables, and you can go from there, but 80 psi is a good place to start.

I agree, start at 80 psi. ST trailer tires are designed to run coolest, and perform best, at full sidewall pressure.

By your numbers, you have moved from an OEM D-rated tire, to a heavier, and higher rated E-rated tire. Endurance, likely does not offer a D-rated tire in your size.

I would not run the E tires at 65 psi. If they ride hard or cause unwanted bounce, I'd lower them to 75 psi, when cold.

It is alright to check tires when hot, as suggested above, but do not let air out to keep them at 80. The tires are designed for the increased pressure of heat, from rolling down the road, at towing speed.

Jerry

[CapriRacer]

Pressure buildup Test:

Check tire pressures immediately before leaving. Ambient temperature, too, if you can.

Run at least an hour, then check again. You don't want more than 10% buildup excluding ambient temperature affects (2% for every 10F).

[fj12ryder]

Without knowing what your weight is, I would go for 80 psi. There are inflation pressure tables, and you can go from there, but 80 psi is a good place to start.