Tire design issue or something else?

[Local150]

Oh no I bought new tires in May,, have about 50 miles on them,just read the posts above and they are Trailer King,, ugh I am sick to my stomach

[jadatis]

The kind of wear on one side indicates an alignment problemm.
This can be because of hitting something, but when I look at picture of your TT hiched up, I see a verry low towbarr so buttum up.
This lifts up the rear axle.

In Europe are some most single axle trailers profided with a Delta- axle, wich give toe in or out alignment when lifted or pushed down.

Placing your towbar higher and / or using a weightdistribution hich, gives straighter TT so both axles in the middle.

I dont know if these Delta-axles are also used for tandem axle TT , but you could find out if so .

Further I enlarged the tire picture and read next
ST225/75R15 8PR 113/108L loadrange D
Maxload 2540lbs AT 65 psi. 8PR is the European eqivalent of D-load.
L is speedcode for maxspeed 120km/75m/ h.
For that speed the maxload is calculated.

If Delta axle I would try to upgrade to LT in E or F-load. Then first follow the advice of Tireman9's post and weigh and take enaugh reserve.
This kind of wear is more if tires deflect more.

[Sk734]

I always run max psi rated on the tire. They run cooler with more air. I have used Carlisle on my 5ver with no problems. Keeping speed down to 60 tp 65 and your tires will last longer. Many people have blowouts at 75 to 85 mph and wonder why. Safe travels

[Harks_723]

Originally Posted by jadatis

The kind of wear on one side indicates an alignment problemm.
This can be because of hitting something, but when I look at picture of your TT hiched up, I see a verry low towbarr so buttum up.
This lifts up the rear axle.

In Europe are some most single axle trailers profided with a Delta- axle, wich give toe in or out alignment when lifted or pushed down.

Placing your towbar higher and / or using a weightdistribution hich, gives straighter TT so both axles in the middle.

I dont know if these Delta-axles are also used for tandem axle TT , but you could find out if so .

Further I enlarged the tire picture and read next
ST225/75R15 8PR 113/108L loadrange D
Maxload 2540lbs AT 65 psi. 8PR is the European eqivalent of D-load.
L is speedcode for maxspeed 120km/75m/ h.
For that speed the maxload is calculated.

If Delta axle I would try to upgrade to LT in E or F-load. Then first follow the advice of Tireman9's post and weigh and take enaugh reserve.
This kind of wear is more if tires deflect more.

Thanks for the reply.
Attached is another photo of the rig setup, the truck for sure squats but I think that other photo exaggerated the "tail up" look.
We do run a w/d hitch - Husky centerline

I'll have them check alignment when they do the axle review Jan 5.

Typically 68mph is our average cruise speed when towing. Never over 75 even when passing.

Again loads of great info here. Thanks everyone.

[Tireman9]

Originally Posted by Harks_723

Thanks for the reply.
Attached is another photo of the rig setup, the truck for sure squats but I think that other photo exaggerated the "tail up" look.
We do run a w/d hitch - Husky centerline

I'll have them check alignment when they do the axle review Jan 5.

Typically 68mph is our average cruise speed when towing. Never over 75 even when passing.

Again loads of great info here. Thanks everyone.

The bubbles/bumps on the inside are evidence of separation. not an alignment issue

You said the RV weighed 10,060# I assume that is the total scale weight for 4 tires.

ST tires loads are calculated based on 65 mph max operating speed (see your owner's manual) tires if in PERFECT balance only have 25# margin assuming your pressure gauge is accurate +/- a couple psi. and you NEVER started traveling without confirming pressure and have NEVER added any weight since getting the RV weighed.


You have not told us the age of the tires or why you think you have a perfect axle to axle and side to side loading.


What does your owners manual tell you to do to confirm weight and inflation?


Have you read my signature or qualifications from my RV tire blog?


Did you read the post on why tires fail?

[Gapopper]

I once had three blowouts on one leg of a trip. I have learned a lot about tires since then. You can’t skimp on quality when it comes to tires. I replace my tires every three years no matter how good they look. I run E rated tires. I also keep the tires off the ground when stored. I purchase my tires from Amazon. I have had good luck with the tire age when they arrive. The date code has been 2 to 6 months old on all the tires that I have purchased from Amazon. You have to be careful purchasing from a dealer too. If the tires have been sitting on a shelf for a couple of years , their life clock has already started ticking down. You want the freshest tires that you can get for your camper. I also purchased TPMS to Monitor the tire pressure and temperature while towing. If a tire starts to lose pressure , you will hear an alarm. This gives you time to pull over before the tire damages your camper.

[Sunnysidebeach]

While the tires on my Keystone Bullet looked in good shape, I replaced them with Goodyear endurance. While I purchased the trailer in 2017 I checked the dates and all the tires that came on the trailer, where manufactured in 2015. The Goodyear endurance tires where also rated at higher pressure, and load rating, which made me happy.

[Rber1234]

What does the Load Index Rating of 117 mean? Saw that on some tires I was looking at but no load rating in pounds

[JRTJH]

Originally Posted by Rber1234

What does the Load Index Rating of 117 mean? Saw that on some tires I was looking at but no load rating in pounds

Go here to read all you'd ever want to know about tire ratings:

https://www.discounttire.com/learn/l...nge-load-index

Scroll down to the Load Index and Load Carrying Capacity to answer your specific question.

[Bttravel]

Experienced the same problem with the same brand factory tires. We have a 2016 Sprinter 319mks that loaded is right at 10K. Had both tires on the same side wearing the outside tread rib. Had the axles checked at a custom trailer build shop and they said no problem with axles or spindles, but they have seen this same problem before on heavier trailers with tires that are just barely rated for the max load. I replaced them with Goodyear Endurance E rated and holy cow what a difference. First thing I noticed was the different in weight of the two tires. You can immediately tell the Endurance is a much heavier built tire, carcass wise and the sidewalls are stiffer. Now that will make for a slightly stiffer road ride for the trailer but the towing and handling difference going down the road was amazing. No more trailer rocking around on less than stellar roads. I was just amazed at how much better the TT pulled. I can tell it rolls easier and so far no sign or any adverse/early wear on the tread. E rated Goodyear Endurance will make a big improvement in your overall towing experience. But like mentioned before, still have the axles and spindles checked just to be sure.

[Brentw]

So what are the opinions on setting the pressure for actual loads, assume a load range G on an E rated axle.
Es call for max 110 psi, trailer sticker calls for 80 psi. Would the extra pressure not cause center tread wear due to over inflation for the load? And a firmer ride?

Never mind, headed over to this thread, http://www.keystoneforums.com/forums...play.php?f=135

[Tireman9]

Originally Posted by JRTJH

Go here to read all you'd ever want to know about tire ratings:

https://www.discounttire.com/learn/l...nge-load-index

Scroll down to the Load Index and Load Carrying Capacity to answer your specific question.

Good and correct information.
RE the specific max tire load capacity ALL DOT approved tires have a statement "Max load 3,000Lbs at 80psi" or something similar. Usually down on the sidewall near the wheel. Statement also gives loadin Kg and inflation in Kpa.
Since it is the inflation that supports the load you have to inflate to the stated level to support the stated load.

[Tireman9]

Originally Posted by Brentw

So what are the opinions on setting the pressure for actual loads, assume a load range G on an E rated axle.
Es call for max 110 psi, trailer sticker calls for 80 psi. Would the extra pressure not cause center tread wear due to over inflation for the load? And a firmer ride?

In trailer application, especially multi-axle trailers, the side slip that occurs in every turn or corner results in much higher shear force that it trying to tear the belts apart.
I cover this in detail, with videos and the Engineering details for those who don't want to accept the word of a retired Tire Design and Quality Engineer.


Trailers should run the inflation molded on the tire sidewall. ALSO you need to confirm the actual tire load at its heaviest is no more than 85% of the ststed tire MAX LOAD.


Check my blog for the posts on "InterplyShear" or just GOOGLE the term.


Peer reviewed published papers are available if need be.



Or just do what I tell you "Because I said So"

[CWtheMan]

Originally Posted by Brentw

So what are the opinions on setting the pressure for actual loads, assume a load range G on an E rated axle.
Es call for max 110 psi, trailer sticker calls for 80 psi. Would the extra pressure not cause center tread wear due to over inflation for the load? And a firmer ride?

Never mind, headed over to this thread, http://www.keystoneforums.com/forums...play.php?f=135

Inflating tires supporting RV trailer axle/tire loads to an inflation pressure to “carry the load” is not an acceptable or approved inflation pressure method for that application. It’s a method use by the commercial trucking industry and their regulations which are found in the Federal Motor Carrier Safety Administration regulations.

Federal regulations and tire industry standards fully support the trailer manufacturer’s recommendations for Original Equipment tires and their replacements.

When considering deviating from the normal methods you must consider the drawbacks. RV trailers are notorious for having overloaded wheel positions. Inflating their tires to the load carried requires each wheel position to be weighed. Then determine the inflation pressure needed to support the heaviest position and inflate all tires to that PSI value. Federal regulations require all tires on the same axle to be inflated to the same PSI. When inflating to the load carried and the load on the heaviest position will require tire inflation that exceeds the tires maximum allowed inflation pressure, you’re going to have to get some weight off that tire position. Inflating tires to the load carried does not provide any load capacity reserves. Older tires may have degraded to the point of needing the load capacity reserves necessary to safely carry the load. There are more obstacles; I’m just going to stop there.

[CWtheMan]

Originally Posted by STJ

I just bought a 2019 Outback 301 ubh.
My dealer and the info on the trailer recommends a tire pressure of 65 psi. I have always ran my trailer tires at max inflation 80 psi and when I checked the tires before leaving with the new trailer they were at 80. Which is were they have stayed for the first trip of 1500 miles.
My gross weight is 9500 lbs.

Were you the first owner of that trailer?

[CWtheMan]

Replacement tires for RV trailers ARE NOT selected on the basis of the scaled load carried. They are selected on the basis of what the OE tires provided in load capacity. And, just like the automotive industry, they normally need to have vehicle manufacturer approval.


Verbatim from the Keystone owner's manual: "To maintain tire safety, purchase new tires that are the same size as the vehicle’s original tires or another size recommended by the manufacturer."


A standard from a respected trailer tire manufacturer, Maxxis.

"It is preferable to replace a trailer’s tires with ones that correspond to the manufacturer recommended specifications."


Remember, I post on how it's supposed to be done. The ultimate decision lies in the hands of the vehicle owner.

[Tireman9]

And as an actual Tire Design & Quality Engineer w/ 40 years experience, I base my recommendations on Science and the results of numerous invistigations on WHY tires fail, not based on a detailed reading of DOT regulations.
Too often "Regulations" are developed to make those that have to live under the regs (rv companies) happy, rather than providing the best information for the end user. Otherwise why wasn't the +10% load capacity adopted for RV applications years ago? Why are the release test requirements for ST tires the same as in 1970 where Passenger and LT tires have newer and tougher test requirements?

Yes you can follow the published regulations or you can do a better job. You can do the minimum required or you can do a better job. You can continue to have tire failures every year or so or you gan get longer tire life. Your decision, your money.

[CWtheMan]

Originally Posted by Tireman9

And as an actual Tire Design & Quality Engineer w/ 40 years experience, I base my recommendations on Science and the results of numerous investigations on WHY tires fail, not based on a detailed reading of DOT regulations. (If you worked for a tire retailer you would have to abide the tire industry standards).
Too often "Regulations" are developed to make those that have to live under the regs (rv companies) happy, rather than providing the best information for the end user. Otherwise why wasn't the +10% load capacity adopted for RV applications years ago? Why are the release test requirements for ST tires the same as in 1970 where Passenger and LT tires have newer and tougher test requirements? (Just maybe because the national highway speed limit was 55 MPH back then with no relief in sight).

Yes you can follow the published regulations or you can do a better job. You can do the minimum required or you can do a better job. (That's sort of a misguided statement. The regulations and standards are to insure we know what the minimum safety levels are. They do not prohibit us from doing better). You can continue to have tire failures every year or so or you can get longer tire life (Than what?). Your decision, your money.

If you would take the time to read the minutes and final decision of the 2007 NHTSA tire rules committee you would know why they shelfed it. The most favorable recommendation at that meeting was 12%.

[jadatis]

Conclusion to what I read in this topic , it is a tiredesign issue AND something else.
What I wrote about the one side wear, based on picture 2 of beginning post, an alignment should be done , ...if possible.... and you should check if tail up of trailer influences the alignment ( the delta axle story) . If so you can put towbar higher ( again if possible, or lower tires ,fi 225/70 R 15 but then in E or F-load .
This kind of uneven wear one side is not a savety issue, in tje Netherlands , where I live , for general periodical checkup its OK as long as you cant see the cordlayer.

But the bulbs on picture 3 indicate overloading or underpressure .
And I see on bulbside enaugh profile, so is the other side of tire picture 2 , or another tire.
For that you need more maximum load a tire .
Strange about LT tire 225/70R 15 , is that D load gives loadindex 112 Q or R speedcode.
This makes me suspect the LT tire to be an exeption in history. So in early days was given this loadindex, and was not chanched afterward.
If this then should be higher or lower, when calculated with the formula used for that, I dont know, mayby Tireman9 can tell.
The ST 225/75R 15 has only 1 loadindex step higher, can be explained bi the 75 instead of 70 .
If for 65mh calculated the 225/70 wold then have loadindex 112+6= 118 .
Or if 225/ 75 was 113 right calculated , the 225/70 would calc for 99mh( Q speedrated or higher) a loadindex of 112- 6 = 106 .

In any case a upgrade of tires I advice, but wich sise and loadrange to take????