tire pressure

CALandLIN wrote:

fj12ryder wrote:

wilber1 wrote:
...

Load inflation tables just tell you how much load a tire can carry at a certain pressure. They aren't recommended pressures.

Actually yes they are recommended pressures. Per Goodyear's RV's Tire Care Guide: "Inflation pressure should be adjusted to handle the tire carrying the heaviest load, and all tires on the axle should be adjusted to this pressure."

This is also in their inflation guide.

Tire pressure should never be reduced below the vehicle manufacturer's recommended levels to support load conditions in order to improve the ride quality of a vehicle. The difference in ride quality is not significant. When minimum inflation pressure requirements are not met, tire durability and optimum operation can be affected.

Well, you can't really go by that since most large 5th wheels come with ST tires and their rated tire pressures given is 80 psi. And I'm not going to put 80 psi in my "G" rated tires. They would probably be fine, but that just seems too low for me.

JIMNLIN wrote:
https://www.goodyearrvtires.com/weighing-your-rv.aspx
Those S637 are tough and can take lots of abuse such as derating with low pressures. Glad you didn't see a reduction in mpg like the silly guy with the H S637's. Your the man.
Goodyear still has the same recommendation of max sidewall pressures for trailers with a unless clause.

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.*

It does make you wonder why they choose to post conflicting information. Since right here is the conflicting part: RV Tire and Care Guide

And, if lessening the air pressure is bad for the tires, why would any tire company give you the chart to set your pressure to the weight being carried by the tire? Or do you know some secret the tire people don't know? Do you suppose they purposely are tying to ruin your tires by giving false data?

fj12ryder wrote:

wilber1 wrote:
...

Load inflation tables just tell you how much load a tire can carry at a certain pressure. They aren't recommended pressures.

Actually yes they are recommended pressures. Per Goodyear's RV's Tire Care Guide: "Inflation pressure should be adjusted to handle the tire carrying the heaviest load, and all tires on the axle should be adjusted to this pressure."

This is also in their inflation guide.

Tire pressure should never be reduced below the vehicle manufacturer's recommended levels to support load conditions in order to improve the ride quality of a vehicle. The difference in ride quality is not significant. When minimum inflation pressure requirements are not met, tire durability and optimum operation can be affected.

https://www.goodyearrvtires.com/weighing-your-rv.aspx
Those S637 are tough and can take lots of abuse such as derating with low pressures. Glad you didn't see a reduction in mpg like the silly guy with the H S637's. Your the man.
Goodyear still has the same recommendation of max sidewall pressures for trailers with a unless clause.

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.*

wilber1 wrote:
...

Load inflation tables just tell you how much load a tire can carry at a certain pressure. They aren't recommended pressures.

Actually yes they are recommended pressures. Per Goodyear's RV's Tire Care Guide: "Inflation pressure should be adjusted to handle the tire carrying the heaviest load, and all tires on the axle should be adjusted to this pressure."

JIMNLIN wrote:
Some folks do silly things like mount a load G tire at 4080-4400 lbs on 5.2k/6k axles with 2500-2800 lb load per tire. Then derate them to 80-90 psi. Most RV folks can get by with it as they don't use a tire long enough to wear it out plus a commercial grade all steel carcass tire like the S637 can take abuse like that. One newby actually went with 17.5" load H S637 at 6006 lbs capacity per tire on his trailers tandem 6k axles with 2550 lb load per tire. Aired them to 80 psi and complained about them running hot and mpg drop for his 6.7 Ford truck.

...

And some of us are well aware of what we're doing, even if you don't like it. I run around 2500 lbs. on each wheel, and also have the Sailun LT S637 rated at about 3700 lbs. FWIW, I have had the Sailun tires for over 5 years and 20,000 miles and run them at 95psi. They show excellent wear, which is basically none BTW, and I intend to continue to do so despite all the horrible things that are forecast for my continued disregard for all the safety "warnings". Oh, and my fuel mileage hasn't changed from my initial setting of 110 psi, which resulted in a very harsh ride.

Other than the Sailun's, I could have bought another set of ST tires, which I had been burned by once already, and had no desire to repeat the process.

Or I could have bought an LT tire and been okay, but they wouldn't have had the same carrying capacity as the OEM tires. Which is no big deal to me except for the dire warnings by some that doing that is a horrible thing and will result in catastrophe. Which is total BS IMO. If the tire will carry the weight with room to spare, what's the harm?

Since I know the weight on each wheel, if I used LT tires with a load rating of 3042 lbs., and I have max of 2500 lbs. per wheel, and a couple with less than that, I would have a "safety margin" of over 20%. Wow, regardless of what the "safety mavens" have to say, I would be fine.

I used to be able to find a recommendation from Goodyear that said it was best to inflate trailer tires to their max sidewall pressure. That particular bit of advice apparently has been rescinded and replaced with this: "Inflation pressure should be adjusted to handle the tire carrying the heaviest load, and all tires on the axle should be adjusted to this pressure." An inflation chart for ST tires followed the quote. Maybe, just maybe, the "safety mavens" need to update their sources.

Unless you know what each tire is carrying, using inflation tables is a bit of a mugs game. There can be big differences in side to side loading on RV tires. If you just divide the weight by the number of wheels, you could be well within limits on one tire and over the limit for another. Because of my rig's layout, my left side tires are carrying 600 lbs more empty and probably more like 900 lbs loaded. To give the same load margin for all my tires, I would have to inflate my LH tires to account for the 450 lbs extra they are carrying. Even then, there could be a difference between front and rear.

Load inflation tables just tell you how much load a tire can carry at a certain pressure. They aren't recommended pressures.

Super_Dave wrote:
I can tell that my rear axle on the trailer has a little more weight on it than the front. I could see running different tire pressures on each axle.

YES you should inflate each axle based on the heaviest tire on each axle. Per GY Tech Support.

"Goodyear Marathons are highly touted on this forum by many." UH, no the Endurance is the GY tire that has ZERO reports of failure on this and many other forums.

"Sorry if my 2 cents bothered you." No it did not bother ME but my generic comments sure bothered YOU. You may want to re read what I actually said and not what you think I said.

Some folks do silly things like mount a load G tire at 4080-4400 lbs on 5.2k/6k axles with 2500-2800 lb load per tire. Then derate them to 80-90 psi. Most RV folks can get by with it as they don't use a tire long enough to wear it out plus a commercial grade all steel carcass tire like the S637 can take abuse like that. One newby actually went with 17.5" load H S637 at 6006 lbs capacity per tire on his trailers tandem 6k axles with 2550 lb load per tire. Aired them to 80 psi and complained about them running hot and mpg drop for his 6.7 Ford truck.



Lots of blogs from industry experts on this subject and they all run about like this one....

rvsafety.com

Tire Load and Inflation Ratings

Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.