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Old 05-02-2021, 05:57 AM   #21
German Shepherd Guy
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Originally Posted by Ken / Claudia View Post
Before taking that cross country trip, do yourself a BIG favor, get new tires.
Running those at the lower PSI could have caused damage from over heating. Besides as you said they have extreme wear now, why used them any longer.

Ditto that!
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Old 05-06-2021, 07:28 AM   #22
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You need a wheel alignment. This is especially true if it was ever jacked up by the axels and not the frame.
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Old 05-06-2021, 07:48 AM   #23
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Originally Posted by Ken / Claudia View Post
Do you know ST trailer tires are designed to be inflated to PSI at max. cold. Check tire side wall for that number and or the placard on the trailer. If your running them at that continue to do so. I 2 the 1st reply, you can guess at your weights, guessing is sometimes way off. So, you do not know what the weights are on each tire and axle until you check.
If the tires are properly inflated and have been and your not over weight, then look further at alinement or tire defects.
Absolutely untrue. They are designed to be run at the pressure specified by the manufacturer for the load they are carrying. Not the # specified as max on the tire.
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Old 05-06-2021, 08:41 AM   #24
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Originally Posted by Ccrew View Post
Absolutely untrue. They are designed to be run at the pressure specified by the manufacturer for the load they are carrying. Not the # specified as max on the tire.
"AVSOLUTE" is always subject to be disproven....

I think you're both correct (to some degree)

My truck, and most others, use LT tires or P series tires and the truck manufacturer recommends a pressure setting for the tires. Ford recommends my LT275 70R18 LRE tires be run at 65PSI (front and rear) while the tire sidewall says "MAX 80PSI"... Most truck manufacturers do recommend a pressure lower than the "sidewall max" for most of their truck applications...

That said, I can't recall ever seeing a RV trailer tire placard that doesn't recommend the maximum sidewall pressure for ST tires listed on the placard...

My Cougar placard states ST225 75R15 LRD to be run at 65PSI. That's also the max sidewall pressure.... Now, I've installed ST225 75R15 LRE tires on the trailer. The max sidewall pressure (molded on the tire) is 80 PSI. If I run them at 65PSI, I'd have exactly the same max weight rating as the LRD tires... So, why buy LRE tires and not take advantage of the added capacity? For that reason, I run my LRE tires at 80PSI, gaining 1160 pounds of added tire capacity (hopefully preventing an overloaded tire situation)....

So, while LT tires do often have a placard recommendation that is lower than the sidewall max PSI rating, I don't think I've ever seen an ST tire placard that doesn't recommend the "max sidewall rating" for the OEM tires... What one does with aftermarket size tires is "entirely up to them" but I'd ask, why buy better rated tires and then air them down to eliminate the increased rating? If you're going to do that, buy the cheaper tires to start with because you're not gaining anything airing them down from their max capacity.
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Old 05-06-2021, 08:54 AM   #25
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"AVSOLUTE" is always subject to be disproven....

why buy better rated tires and then air them down to eliminate the increased rating? If you're going to do that, buy the cheaper tires to start with because you're not gaining anything airing them down from their max capacity.
I'll give you a good example. I swapped out my China bombs for the exact same size in Endurance. Trailer placard says 65psi. Goodyears tire chart for the CAT scale weight of my TT says 65psi. If I run 85 which the Endurance tire says on the side I get an overinflated tire that rides on the center of the tread because the weight doesn't deform the tire enough to get the proper tread pattern. I also don't get a tire that will deform over bumps the way it's designed to do when loaded properly. I simply have an overinflated tire. Safety margin? Better quality tire designed an run as the manufacturer designed it for rather than internet speculation. If you're loaded heavy then you should CAT scale the trailer and adjust pressure accordingly. That you CAN do that vs a lesser tire is the safety margin.
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Old 05-06-2021, 10:16 AM   #26
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I changed out my under rated E tires for ST G rated Sailun tires. Keystone switched to F rated tires after 2018 because the E rated tires were under rated for the size/weight of my 5er. I run them at 107 psi cold and are rated at 110 PSI. My tires wear evenly now and cooler. They roll down the road smoother. They will age out before they wear out. The placard on my rig is also incorrect as it states 80 PSI for E rated tires, that are both under rated for my rig. I have spoken with several “experts” and all have said I’m good to go with my tire inflation,. Obviously, the tires can handle it so I’m fine with 107 PSI. I would rather be a little over based on inflation charts than under. I do have a TPMS so I m good to go.
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Old 05-06-2021, 10:43 AM   #27
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Originally Posted by Ccrew View Post
I'll give you a good example. I swapped out my China bombs for the exact same size in Endurance. Trailer placard says 65psi. Goodyears tire chart for the CAT scale weight of my TT says 65psi. If I run 85 which the Endurance tire says on the side I get an overinflated tire that rides on the center of the tread because the weight doesn't deform the tire enough to get the proper tread pattern. I also don't get a tire that will deform over bumps the way it's designed to do when loaded properly. I simply have an overinflated tire. Safety margin? Better quality tire designed an run as the manufacturer designed it for rather than internet speculation. If you're loaded heavy then you should CAT scale the trailer and adjust pressure accordingly. That you CAN do that vs a lesser tire is the safety margin.
If I remember correctly, last year you replaced your 205 75R14" LRD tires for 15" 225 75R15 LRE tires and changed the wheels at the same time. According to all the Goodyear Endurance specs I can find, the max pressure on the Endurance LRE line is 80PSI. You might want to check the actual molding on your tires. Goodyear may have an issue with a lot or two of their tires and you might get "new tires on the recall" if they molded the incorrect max pressure on the sidewall...

That said, attempting to compare "lesser tires" to your "overbuilt tires" is not an OEM or a "factory tire placard" issue... You've completely eliminated all reference to the factory tire placard when you replaced 8-ply 14" tires/wheels with 10-ply 15" tires/wheels. Nothing on your placard (other than what used to apply) is relevant any longer.

As an example, if I installed 17.5" 16-ply tires on my trailer (with an OEM placard for 15" 8-ply tires) and aired them up to the sidewall pressure of 125 PSI, those tires would "ride on the center thread" too....

What you've got is not the "generally applied tire pressure recommendations" for tire replacement. You've completely "sideswiped" the manufacturer and the placard with upsizing like you did. The "normal rules don't apply to you any longer"....
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Old 05-06-2021, 01:54 PM   #28
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Ccrew, I stand by my post.
As was pointed out, you changed out tire and wheel size.
#1 could your center tire wear be due to a wheel too narrow for the tire? That is a cause for center of tire wear besides over inflation.
#2a did you run your replacement tires at the max psi and really see center tire wear.#2b are just assuming that would happen?
#3 At max psi, did the tires not deform the way you wanted over bumps or are you assuming?
#4 what is the proper deforming of a tire needed over bumps?
#5 how do you measure them deforming at a good or bad deform?
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Old 05-06-2021, 02:05 PM   #29
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My 2020 High Country has at most 5K miles on it and I'm seeing extreme wear on the outside of all four tires.

The Camping World techs say I'm probably overloading it, the Les Schwab websites say I'm underloading it. The specs say 11367 dry weight, 14260 GVWR. I'm finding it hard to believe that the dishes, pots, pans, and clothing are pushing the 2893 payload. We had a washer & dryer added when we bought it but that should still give me 2300 lbs? And my storage compartments are FAR from packed.

At this point I'm on the verge of a cross country trip and the dealer can't "touch" it for a couple months. I saw on another thread where someone had Les Schwab, Bridgestone, or some tire dealer swap the tires to put the warn side on the inside.

With all four tires showing outside wear, though particularly the passenger side rear tire, I'm interested in opinions and discussions on how to proceed. Over inflate? Add more weight? Remove weight (not sure what I'd take out!)



1. Stop trying to estimate the weight. Get on a truck scale and get each axle weighed on a different pad and learn the facts.
If weights are OK then get the alignment checked. Check locally to find a good shop as not all "alignment shops" can properly check or fix RV trailers.
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Old 05-06-2021, 02:11 PM   #30
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Y'all have pretty much convinced me I should get new tires.

Question, do you all inflate your tires to the MAX PSI? Or leave some "head room", noting that the MAX PSI listed for these tires is COLD PSI?

I'm surprised that they were 20lbs below the MAX delivered "from the factory". They didn't "look" underinflated. But I know with my car tires, which I might normally run at 45, 20lbs below they LOOK flat.

I just checked the Michelins on my Silverado - MAX 80PSI and testing them, they're at 75PSI. So maybe running the Fifth Wheel at 90PSI is best, and at 72 out of the factory, they WERE under inflated.





Tires do NOT need "head room". The inflation on the tire sidewall is actually the MINIMUM needed to support the stated MAX load. Do NOT worry about your hot pressure as long as you have confirmed your actual scale weight on the tires. The load on each tire IS NOT the total on the trailer divided by 4 as the load is not split 50/50 between the axles or 50/50 side to side on the axles.
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Old 05-06-2021, 06:21 PM   #31
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Well, it looks like they're under-inflated. The tires are ST235/80R16Fs, and it the sticker on the side says 95PSI cold. I got out a "questionably accurate" pressure gauge and its saying 72PSI. SO, I'll see about inflating them 95PSI and try to get a more "reliable" pressure gauge!
Here we go.

Inflating RV trailer tires to the load carried is not a recommended USTMA procedure, unless, the adjustments are at or above the vehicle manufacturer's recommended cold inflation pressures. The basic USTMA wording is; "never use inflation pressures below the vehicle manufacturer's recommendations".

According to tire industry standards, any tire found to be underinflated by 20% should be removed from the wheel for an internal damage inspection.

To maintain the vehicle manufacturer's minimum inflation for replacement tires will require the installer to find and set a new recommended cold inflation pressure for the replacement tires. The basic tire industry wording is; "replacement tires must provide a load capacity equal to or greater than what the OE tires provided".

Setting the stage for using full sidewall inflation pressures for RV trailer tires: It's antiquated and goes back to the days when Carlisle Tire ruled the roost, so to speak. In their trailer tire brochures (back in the day) they had wording that recommended the use of full sidewall inflation pressures for their ST. Of course it was just a recommendation because the vehicle manufacturer's have the sole responsibility for setting recommended cold inflation pressures for all OE tires. It was also misleading because any highway tire can be operated at full sidewall inflation.
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Old 05-06-2021, 06:31 PM   #32
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Originally Posted by meyerdp View Post
Y'all have pretty much convinced me I should get new tires.

Question, do you all inflate your tires to the MAX PSI? Or leave some "head room", noting that the MAX PSI listed for these tires is COLD PSI?

I'm surprised that they were 20lbs below the MAX delivered "from the factory". They didn't "look" underinflated. But I know with my car tires, which I might normally run at 45, 20lbs below they LOOK flat.

I just checked the Michelins on my Silverado - MAX 80PSI and testing them, they're at 75PSI. So maybe running the Fifth Wheel at 90PSI is best, and at 72 out of the factory, they WERE under inflated.
The driver of the delivery vehicle may have been a licensed CDL driver and more familiar with inflation pressures set to load carried. That is a standard procedure for commercial tires and is outlined in the trucker tire FMCSA regulations.
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Old 05-06-2021, 06:45 PM   #33
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I changed out my under rated E tires for ST G rated Sailun tires. Keystone switched to F rated tires after 2018 because the E rated tires were under rated for the size/weight of my 5er. I run them at 107 psi cold and are rated at 110 PSI. My tires wear evenly now and cooler. They roll down the road smoother. They will age out before they wear out. The placard on my rig is also incorrect as it states 80 PSI for E rated tires, that are both under rated for my rig. I have spoken with several “experts” and all have said I’m good to go with my tire inflation,. Obviously, the tires can handle it so I’m fine with 107 PSI. I would rather be a little over based on inflation charts than under. I do have a TPMS so I m good to go.
At the time of vehicle certification the vehicle manufacturer MUST attest that the installed OE tires set at their recommended cold inflation pressures are appropriate for that trailer.

If you must rebuke someone, it's NHTSA, they are responsible for setting the minimums.
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