Upgraded tires

[CWtheMan]

Originally Posted by rhagfo

Well to you and John, I think G rated tires on a 14,300# 5er are over kill! Second running a tire inflated to cover the load make a lot sense to me. The 235/75-16 on our Ram DRW only call for 65 psi for full axle rating weight of 9,750#. Putting G rated tires on the OP’s 5er means the are overinflated for load carried, rougher ride, and less tread contact with the road, poor wet weather braking.
I had a neighbor who ran log trucks, he only aired his tires up to 90 psi, tires rated to 110 psi. I don’t remember him ever throwing a cap, the only blowout was on an almost new tire on his tag axle. Dropping the inflation greatly reduced the tread cuts from the logging roads. Which resulted in near zero tire failures.
I run the LT tires on our 5er at about 75 psi as I only have about 10,000# on tires rated at 3,042# each or 12,168# total.
In reality the OP
Should have gotten good quality F rated tires and inflated accordingly.

You know? you can't compare inflation pressures for your truck tires to those on RV trailers. The standards are different. Your truck GAWRs are in excess of the ultimate limiter, the GVWR.

I'm pretty sure the Original Equipment tires on your RV trailer were LT235/85R16 LRE. Keystone set the inflation pressures for those tires at 80 PSI. At 75 PSI you are below the minimum load capacity for 6000#axles.

There are no provisions in the regulations and standards to use inflation pressures below what has been set by the RV manufacturer and displayed on the vehicle certification label.

FMCSA regulations are not applicable for vehicles certified in accordance with FMVSS - standards.

[travelin texans]

Originally Posted by rhagfo

Well to you and John, I think G rated tires on a 14,300# 5er are over kill! Second running a tire inflated to cover the load make a lot sense to me. The 235/75-16 on our Ram DRW only call for 65 psi for full axle rating weight of 9,750#. Putting G rated tires on the OP’s 5er means the are overinflated for load carried, rougher ride, and less tread contact with the road, poor wet weather braking.
I had a neighbor who ran log trucks, he only aired his tires up to 90 psi, tires rated to 110 psi. I don’t remember him ever throwing a cap, the only blowout was on an almost new tire on his tag axle. Dropping the inflation greatly reduced the tread cuts from the logging roads. Which resulted in near zero tire failures.
I run the LT tires on our 5er at about 75 psi as I only have about 10,000# on tires rated at 3,042# each or 12,168# total.
In reality the OP
Should have gotten good quality F rated tires and inflated accordingly.

The Gs may be overkill, but if properly inflated to max load pressure, at least what's posted on the rv tag, they'll never have to worry about tires again for the load they're carrying. Running tires recommended for 110 psi at 75 psi is running them flat in my opinion, no benefits from the upgrade at all, 95 psi would be a much better pressure if lower seems necessary. Also properly inflated rv tires aren't going to be affected by wet road surfaces anymore than seriously under inflated ones, both will slide equally.
Running extremely under inflated at the 75 psi seems that you could easily peel them off the wheels when scrubbing the tires backing in at extreme angles, properly inflated roll bad enough.
Your running LT tires on the rv at 75 psi, what's the max load rating pressure on the sidewall, 80 psi?
Comparing rv tires to truck, or any other vehicle, is like comparing apples to bananas.
Had a co worker that thought his 1/2 ton pickup rode too rough, so rather than inflating the tires to the recommended 45 psi, or whatever it was, ran his at about 25 psi. Yeah it may have rode better but handled like crap with those squishy squirmy tires oozing you all over the road & would ruin at least 1 a month with a thorn or something through the sidewall. He had so many tire issues he carried 2 spares & sometimes that wasn't enough. BUT he liked the ride!!!

[JRTJH]

Originally Posted by travelin texans

...
Had a co worker that thought his 1/2 ton pickup rode too rough, so rather than inflating the tires to the recommended 45 psi, or whatever it was, ran his at about 25 psi. Yeah it may have rode better but handled like crap with those squishy squirmy tires oozing you all over the road & would ruin at least 1 a month with a thorn or something through the sidewall. He had so many tire issues he carried 2 spares & sometimes that wasn't enough. BUT he liked the ride!!!

Seems I remember a 1997/1998/1999 problem with Ford/Firestone.... As I recall, it was all based on running "underinflated tires".... The operating characteristics of tires hasn't changed much over the years... All of that problem was attempting to "create a luxury car ride" in a SUV....

[rhagfo]

Originally Posted by travelin texans

The Gs may be overkill, but if properly inflated to max load pressure, at least what's posted on the rv tag, they'll never have to worry about tires again for the load they're carrying. Running tires recommended for 110 psi at 75 psi is running them flat in my opinion, no benefits from the upgrade at all, 95 psi would be a much better pressure if lower seems necessary. Also properly inflated rv tires aren't going to be affected by wet road surfaces anymore than seriously under inflated ones, both will slide equally.
Running extremely under inflated at the 75 psi seems that you could easily peel them off the wheels when scrubbing the tires backing in at extreme angles, properly inflated roll bad enough.
Your running LT tires on the rv at 75 psi, what's the max load rating pressure on the sidewall, 80 psi?
Comparing rv tires to truck, or any other vehicle, is like comparing apples to bananas.
Had a co worker that thought his 1/2 ton pickup rode too rough, so rather than inflating the tires to the recommended 45 psi, or whatever it was, ran his at about 25 psi. Yeah it may have rode better but handled like crap with those squishy squirmy tires oozing you all over the road & would ruin at least 1 a month with a thorn or something through the sidewall. He had so many tire issues he carried 2 spares & sometimes that wasn't enough. BUT he liked the ride!!!

Yes, the LT tires on our 5er have max of 80 psi. I don't back in at extreme angles, and 5 psi isn't going to change bead holding a bit. I actually run my rears at 55 psi, as I am about 2,000# under the max axle rating.

As to your co-worker, his F150 likely had P rated tires so running at 25 psi wasn't good.

If tires were not adjustable for load carried why would tire manufactures publish load table, and why would the Yellow Sticker on my DRW state for max rear axle load of 9,750# state inflation to 65 psi, not the 80 PSI on the sidewall. Well the WHY is at 80psi the tire would be OVERINFLATED for the load carried, and would give a contact pattern like the over inflated in the picture below.

[CWtheMan]

Originally Posted by rhagfo

Yes, the LT tires on our 5er have max of 80 psi. I don't back in at extreme angles, and 5 psi isn't going to change bead holding a bit. I actually run my rears at 55 psi, as I am about 2,000# under the max axle rating.

As to your co-worker, his F150 likely had P rated tires so running at 25 psi wasn't good.

If tires were not adjustable for load carried why would tire manufactures publish load table, and why would the Yellow Sticker on my DRW state for max rear axle load of 9,750# state inflation to 65 psi, not the 80 PSI on the sidewall. Well the WHY is at 80psi the tire would be OVERINFLATED for the load carried, and would give a contact pattern like the over inflated in the picture below.

Load inflation pressure tables are not recommendations. They are provided by tire manufacturers and standardized by the Tire and Rim Association (TRA). Vehicle manufacturers set recommended cold inflation pressures from tire inflation charts. Tire inflation charts are a necessary tool when plus sized tires are installed because they will need new recommended cold inflation pressures to be set by the installer.

The maximum inflation pressure shown on a tire's sidewall is not a recommendation. It is the inflation pressure for the maximum load capacity of the tire. All tires are designed to be operated at maximum cold sidewall pressures.

There are numerous NHTSA and USTMA documents that explain recommended cold inflation pressures. They will all say the correct inflation pressures for your tires will be found on the vehicle certification label, tire and load placard and in the vehicle owner's manual. If there are options/deviations they will be explained in the vehicle owner's manual. The recommendations and standards found on vehicle certification labels are minimum standards for the safe operation of the vehicle.

Here is a quote from FMVSS that solidifies the recommended cold inflation pressures to be minimum: "The size designation and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle is appropriate". (That APPROPRIATE is the sole responsibility of the vehicle manufacturer). Any tire inflation pressures between what is recommended and tire sidewall max is optional.

[ChuckS]

Originally Posted by cwtheman

are you reading the wheel information? Hispec wheels are primarily oem for many trailer applications. To my knowledge they do not make tires.

hispec tire brochure

[flybouy]

Perhaps my logic is flawed but I don't understand installing a higher rated tire then deflating it. Most folks go up a letter rating to increase the weeight capacity therby increasing the % safety margin. I did this on by going from the D rated 15's to an E rating. Why? to compensate for what I thought was a "marginal" weight rating.

So upgradeing the tire to compensate to a higher rating it isn't logical to me to then reduce the tire pressure therby reducing that safety nmargin to compensate for a percieved harsh ride. If I were going to that then logically I would have to conclude the manufacturers choice for a D rated tire was appropriate for the weight vs ride.

[JRTJH]

Originally Posted by flybouy

Perhaps my logic is flawed but I don't understand installing a higher rated tire then deflating it. Most folks go up a letter rating to increase the weeight capacity therby increasing the % safety margin. I did this on by going from the D rated 15's to an E rating. Why? to compensate for what I thought was a "marginal" weight rating.

So upgradeing the tire to compensate to a higher rating it isn't logical to me to then reduce the tire pressure therby reducing that safety nmargin to compensate for a percieved harsh ride. If I were going to that then logically I would have to conclude the manufacturers choice for a D rated tire was appropriate for the weight vs ride.

People do it all the time don't they??? Buy a 5 gallon gas can to replace the older one gallon gas can, then only fill it with one gallon of gas because it's lighter and easier to lift into the back of the truck ......

Your point is exactly what I was trying to say in my previous posts... Why buy tires rated at 4000 pounds to "upgrade" tires rated at 3000 pounds, then air down the new tires so they only support 2800 pounds ???? Seems a totally futile attempt at "improving" anything.....

[JRTJH]

Originally Posted by ChuckS

hispec tire brochure

Comparing that tire (if their advertising is correctly representing the HISPEC tire) to they Sailun S637T tire, they are entirely different tire technologies...

This is the advertisement "bullet statement" from HISPEC's ad:

Durability for any towing situation is achieved through the use of premium high density polyester body plies, high strength steel belts, and a nylon overlay.

The bolded/red parts were identified by me, not by HISPEC...

The Sailun S637T is an "all steel highway rib tire" and is presented in Sailun's advertising as:

The Sailun S637T is an all-steel highway rib tire designed to provide the ultimate in performance for trailer applications. The heavy-duty, all-steel construction delivers low rolling resistance, superior strength and durability,

The way I read the ads, the HISPEC "G series tire" is a "heavier 14 ply rated version of the typical "polyester corded ST tire design" while the Sailun S637T is a 14 ply rated "all steel construction with no polyester cording"...

Two ENTIRELY different tire construction technologies..... Did I miss something in the translation ????

[ChuckS]

Nope.. you have stated what I read also.. Why Keystone Alpine is putting that cheap tire on when the Montana line ( both luxury class ) fifth wheels comes OEM with Sailun is beyond me...

The Sailun or Hercules 901 series is what Ill upgrade mu six year old G rated tires to later this year or next... They have served me well and are steel belted heavy tires... HISPECs tire doesn't appear to measure up to either...

An I run my tires between 105 to 110 lbs and have for the last six years and the fifth wheel rides smoother and better then it ever did with its OEM E rated crap

[travelin texans]

This is turning into ANOTHER no win everyboby's right, everybody's wrong tire discussion!
I'll say this then I'm done!
I ran ST tires on every rv I've owned inflated to or within 5 psi of max pressures, no issues with ride, braking, abnormal wear & typically at the end of 4-5 years they were evenly worn & replaced.
On every vehicle I've owned I've put the best tire I could afford at the time & inflated to either the sidewall pressures or the manufacturer suggested pressures, again no issues ride, braking, abnormal wear & replaced as needed with the best I could afford at the time.
If others chose the run LT (light truck) tires on heavy RVs or upgrade to a heavier rating STs & then deflate to compensate for the ride then by all means do what makes you happy & gives you peace of mind, just as I will.

[CWtheMan]

Steel cased Sailun tires are an offshoot of their commercial steel cased truck tires. As such, they can be recapped. In all probability they are more durable because of that design characteristic. However, they do not have the ability to be used on steer or drive axles because those features are not in their design - ST.

The ability to carry a load is provided by inflation pressure. There isn’t any difference between the polyester/all steel tires when it comes to load capacity. Each designated size and load range will carry equal loads. It’s all in the manufacturing materials and ply ratings.

[h8ster]

This is a New to me 2015 Outback 230trs... (October 2020]

Last Friday, New Goodyear Endurance Tires including spare!

ST225 /75 R15 117N E1 BSW

The Manager at Discount Tires made me a smokin deal!

[JSisemoreTX]

Originally Posted by JRTJH

Maybe someone else might have a different opinion, but here's mine:

First, tire load carrying capability is directly impacted by the tire pressure. It's the air that carries the load, not the rubber sidewalls. With that in mind:

1. Sidewall flex is the main reason for heat buildup in trailer tires. Reduced tire pressure is the main reason for sidewall flex....

2. The reason for buying "oversized tires for an RV" is to increase the tire capacity to prevent "running on the bare minimum capacity" thus avoiding a blowout.

3. To buy G rated tires that are capable of carrying 4000 pounds and then "airing them down" so they can only support 3000 pounds (like the tires they replaced) is an "exercise in futility"...

Running a G rated tire at (or below) E rated pressures makes it an E rated tire. You've negated all of the potential increased safety margin and reliability from the better tire.

If you're going to "only use half the new tire capacity" then why not just reinstall the same tire as what was on the trailer? There's no improvement in safety or in carrying capacity and no increased safety margin if you don't take advantage of the new tire's capability.....

YMMV

Agree with JRTJH, ^^^ and well articulated.

[JSisemoreTX]

Attached, a pic of the High Spec OEM (G Rated, 110 max psi) tire that came on my 2020 Keystone Avalanche 5th wheel. Less than 7,000 miles on it.....tires were inflated to 105 psi (cold). Was traveling 68 mph in route to Big Bend Natl Park near Marfa.

Pics below.

https://www.keystoneforums.com/forum...ad.php?t=46507

[rhagfo]

Originally Posted by JSisemoreTX

Attached, a pic of the High Spec OEM (G Rated, 110 max psi) tire that came in my 2020 Keystone Avalanche 5th wheel. Less than 7,000 miles on it.....tires were inflated to 105 psi (cold). Was traveling 68 mph in route to Big Bend Natl Park near Marfa (BFE).

No picture

[rhagfo]

Originally Posted by JSisemoreTX

https://drive.google.com/file/d/1LxT...w?usp=drivesdk

Did this link above work? May have to make my own post.

I need to request access.

[JRTJH]

Originally Posted by rhagfo

I need to request access.

He posted what I think are the same photos on the forum in this thread: https://www.keystoneforums.com/forum...ad.php?t=46507

[rhagfo]

Originally Posted by JSisemoreTX

Attached, a pic of the High Spec OEM (G Rated, 110 max psi) tire that came in my 2020 Keystone Avalanche 5th wheel. Less than 7,000 miles on it.....tires were inflated to 105 psi (cold). Was traveling 68 mph in route to Big Bend Natl Park near Marfa (BFE).https://drive.google.com/file/d/1LxT...w?usp=drivesdk

Well unknown brand doubt running at 105, instead of 110 made any difference, likely just quality control!

[JSisemoreTX]

Originally Posted by JRTJH

He posted what I think are the same photos on the forum in this thread: https://www.keystoneforums.com/forum...ad.php?t=46507

Yes I just pisted a new thread so I could easily post the pics. Similar topic for sure!