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Old 02-23-2021, 02:58 PM   #41
Rocketsled
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I don't have an easy answer for that. I've met some really...interesting...people camping. It might be that they get directed to a FAQ and it takes the brunt of the 'You're stupid, you're doing stupid things.'

This...hobby/lifestyle/whatever sure is light on helpful information sometimes, and plenty of people that'll tell you what you want to hear to make the sale, or get you out of their hair at the end of a really short warranty on a box made as cheaply as possible.

There oughta be a secret handshake or something.
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Old 02-23-2021, 07:26 PM   #42
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The "secret handshake" is finding VALID information on which to base your research and repairs....

As an example (and I'm not picking on you), just using YOUR posted information to highlight some examples of "good and bad" information. As I post your links, I'll try to explain why it's "good or bad"...

First, in post #6, you posted a link to a Trailer King tire inflation/load chart:

https://fifthwheelst.com/documents/T...lation2014.pdf

That chart is dated Jan 21, 2014. It is a "composite chart" and EVERY tire size is listed with a "combined load range" that's built in that tire size. As an example, the ST225/75R15 lists "inflation pressures/capacity" for load range B, C, D and E tires. THAT IS 1 TIRE SIZE IN 4 DIFFERENT LOAD RANGES. In reality, that is 4 different tires, all listed on one line of a chart. It is NOT one tire used in 4 different applications.

The chart depicts four different tires, all the same 225 mm of tread width, built with load range ratings of 4ply (LRB), 6ply (LRC), 8ply (LRD) and 10ply (LRE). That chart depicts the carrying capacity for each of those tires, it is NOT a chart that allows you to "pick and choose" the best pressure to run a 10 ply tire being used in a 4 ply application.... Also note the outdated speed rating of 65 MPH.

There is also a disclaimer: "FOR ST TRAILER TIRES USED IN NORMAL HIGHWAY SERVICE" with no explanation of what that disclaimer means.... Is a fifth wheel "normal highway service" for that tire??? Or is a fifth wheel a "special service application" ??? You'd have to go back to the 2014 Trailer King criteria to find out....

Then, in post #2, you listed a link to a more current TK tire load/inflation chart: https://www.towmaxtires.com/tire/details/towmax-str-ii

In that chart, EACH TIRE SIZE AND PLY RATING are separately listed. In this chart, THERE IS NO LOAD/PRESSURE APPLICATION TO LOWER THE PRESSURE FROM THE LOAD RATING FOR A 10 PLY TIRE AND USE IT AS A 8 PLY TIRE.... What TK has done in this chart, is eliminate what you see in the 2014 (outdated) chart. I'd say the reason they changed the chart configuration is to eliminate the "misconception" that you can simply "air down a LRE tire to 50PSI because the "chart says" that size tire at 50PSI can carry a reduced load.... The current TK charts DO NOT allow reduced air pressure on any load range tire to "accommodate less pressure/less load capacity"....

If you look at the current TK chart that you linked, in the 14", 15 and 16" tire sizes/load range ratings, each tire is a line entry with a specific TK tire model and a single, specified load range, pressure requirement and carrying capacity. Gone is the "pick and choose your pressure" in the older charts.

Look at the charts, compare what "they used to allow as a misconception" and how they "eliminated that potential with the new chart configuration"...

My point is, with the new charts, there is no application where you'll find a 235/80R16 LRE tire where there's a pressure/load capacity rating for 50PSI or 65PSI. TK eliminated any chance for an owner to "think the chart says I can air down my tires"....

NOWHERE in the current TK inflation chart will you find a load range for a 235/80R16 LRE tire that gives you a tire capacity if you run that tire at 65PSI...

I'm not intending to confuse you (hope I haven't) and I'm not trying to belittle you or your research. I'm just trying to use your information that you provided, to highlight how both of those documents "contradict" each other, in how the information is presented and how it's intended to be interpreted.

Your tires, on your trailer (according to the manufacturer's data, found on the decal you posted) are intended to be 235/80R16 LRE tires, run at 80PSI. Your tires are MAX24T* and that is the ONLY line in the current chart that you can use to inflate YOUR MAX24T* tires. None of the other lines apply to that specific model/size Trailer King Tire.

Now, as to the question of whether the axle assemblies are the right ones, the tires are the wrong ones or the trailer GVW is incorrectly stated.... I'll leave that to be determined by Keystone's engineering/safety compliance experts....

But, your tires, according to that placard, do not permit you to "safely deflate your tires to 70 PSI to smooth the ride"... The current TK tire load/inflation chart also doesn't even list a load range for your tire when inflated to 50 or 65 or 70 PSI.

I hope this makes some sense to you... All the manufacturers are "tightening the interpretation of charts" by eliminating their "old shortcuts to make the chart easy to read" because, in many situations, the charts left too much for people to "wrongly interpret".... These two charts, well, the 2014 version, is a perfect example of how that could happen.... I'd guess that Trailer King never intended for people to use that chart to "interpret that it's OK to run a LRE tire at 50 PSI and use it at that pressure as a replacement for a LRC tire.... But that's what the chart "implied". The current chart eliminates that misconception by listing each tire by size/model/pressure/load capacity as an individual line item. You can't use the other lines for other tires to apply to your tire model.

Hope this is more than "clear as mud"....
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Old 02-23-2021, 07:36 PM   #43
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The "secret handshake" is finding VALID information on which to base your research and repairs....

In addition to the above, posting ALL pertinent information needed or requested assists members in giving an informed response. Refusing to provide it, for whatever reason, and continuing down a path of questioning that only the poster knows the answer to is simply asking for the same kinds of responses received here.
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Old 02-23-2021, 08:19 PM   #44
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Thanks guys, that makes complete sense. I'd (incorrectly) interpreted the differences in charts to be a 'light and fluffy' page vs a more detailed one....not an older, more open to misinterpretation chart vs a newer one.

I'll set it at 80 psi and leave it there.


Edit: But... Goodyear's guide doesn't clear things up....not that I'm really inferring they're remotely similar tires.

https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

Regardless, I'm just going to take the system as it currently sits, aligned and with the upgraded suspension bits, and observe how they run at 80 psi.


Edit:Edit:Edit: Ah... 'These tables are current as of 06/16/17'
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Old 02-23-2021, 08:48 PM   #45
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Quote:
Originally Posted by Rocketsled View Post
T...
Regardless, I'm just going to take the system as it currently sits, aligned and with the upgraded suspension bits, and observe how they run at 80 psi....
Once you observe how things go, if you're still having issues with vibration/bouncing/rough travel, I'd seriously consider adding shocks. Every trailer that I've had has had "bounce issues". My current Cougar has the CRE 3000 equalizer system and it's a marked improvement over the "steel equalizers"... That said, our Holiday Ramber and Airstream both had shocks. The HR had springs and shocks and rode just as smooth as the Airstream which had torsion axles and shocks. So, comparing those two, one with springs one with rubber torsion axles, it is the shocks (IMHO) that made the difference.

ADDED: One guess as to why the GY inflation chart is not as detailed is the "legal history" of Trailer King tires... TK's have a long and very sordid history of "explosions" With that comes a lot of 'legal assault on the company" from irate customers... My guess on why TK has such a detailed load capacity/inflation chart and limits any use "other than what's listed" is more to protect themselves from further "legal losses in court"... I may be wrong on that, but after you get "stung enough times" you stop swatting the bees and cover your butt so they can't get to you any more.... So, a very detailed, ONE USE chart as CYA.... JMHO....
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Old 02-23-2021, 08:52 PM   #46
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You’re not the first person I’ve heard say that (in this thread, no less). I’ll put it on the watch list...honestly I’m feeling a bit done throwing the money at this part of the trailer.
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Old Yesterday, 09:21 AM   #47
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Calculated for your given info in post #??
With the pictures.
Used nex in my made extra safe spreadsheet .
Weigt on 2 axles 4 tires 10000 lbs.
Lowered the 124 loadindex by 6 steps to 118, to give the tires a deflection needed for 99mph, and added 11% to the 10000lbs.
Gave 77 psi as advice, and this is with maximum reserve, withhout bumping or things all over the place.

And I did not care about the official rules of tires needed for 7000 axles. Only looked at it by rules of nature.

The 10000 lbs weight was fully loaded you wrote, and the 11% adding is done to cover unequall loading RL, wich can even be crossed between the axles.

But also to cover inacuracies in measurement of pressure and weight.
Have to look back if your loadindex for the sise is given , as most ST , for 65mph, if 75mph as L speedcode suggests, Only 4 LI steps less so 120 loadindex. Will come back to that in a next post.
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Old Yesterday, 09:31 AM   #48
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Just saw this thread today. Saw some good answers.


I would point out that if the Certification Label has incorrect (non-compliant) information there is no "Statute of Limitations" as far as I know so Keystone better be interested in taking some corrective action (recall notification). You can get that started by 1. Filing a complaint with NHTSA and provide appropriate pictures and data. - They are not interested in your ride complaint only in the incorrect tire/GAWR info and 2 Notify Keystone in writing with a picture of the label and letting them know you have filed a complaint with NHTSA. NHTSA will provide you with a ref number after you file the complaint. You can tell Keystone of the complaint number.


Keystone & NHTSA will work out what actions, if any are appropriate.


RE Inflation tables and charts. There seems to be a tendency for the RV MFG to cut costs and not provide specific manuals for each model RV. It appears to be cheaper to just dump a bunch of brochures and documents in a box and give that to the new owner to figure out what information applies to his specific unit. This is one reasons that for tires a "Load/Inflation table" is provided rather than a specific chart just for the one tire provided on the RV.


Yes almost all ST type tires have the same table numbers and the intention is for the vehicle manufacturer to use the table to select the appropriate tire and inflation for each specific application. But again that means someone at the RV Co has to stop and think about what they are doing. Actual car companies have teams of engineers doing this work while it appears the RV Co have decided the new owner can figure it out.


IMO ride & durability of RVs would be much improved if tires and inflation number were selected such that the Reserve Load was closer to what is seen in cars (25% to 40%) rather than the current 10%. But that would increase the cost per unit by maybe $50 to $100 and since the RV trailer market is so price sensitive that is not something any RV company wants to do. Providing appropriate Shocks would be another cost increase.
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Old Yesterday, 11:22 AM   #49
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Quote:
Originally Posted by Rocketsled View Post
..............New Powerking Tow max tires were installed..............Which comes to my question:..............50 psi seems...kinda crazy low. The last set of tires were run at 80psi. Does it seem safe to run, say, 60 psi.....
What specific Powerking Tow Max tires did you install since they have a range of tires shown in the link below and what is your trailer's GWVR? 50 psig OR UP To 100 psig could be the correct psi depending on the tire. Recommend G rated tires for travel trailers. My Montana fifth wheel has Sailun Radial ST235/80R16G (14 ply) tires filled to maximum cold pressure of 110 psig.

https://www.towmaxtires.com/tire/details/towmax-str-ii
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Old Yesterday, 08:41 PM   #50
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Quote:
Originally Posted by Rocketsled View Post
50 psi seems...kinda crazy low. The last set of tires were run at 80psi.
Does it seem safe to run, say, 60 psi (2870 lbs) to cut down on the screws backing out due to vibration and reduce the sawdust we have to sweep up at the end of each drive? I'm a bit concerned we're going to use the trailer up prematurely by shaking it apart.
Rocketsled... I'm a bit of a maintenance nerd. I read everything before buying, and refer to all the instructions and charts.
The question you are asking is one that I have questioned myself. Putting too much air for the load that's on each tire, is a bad thing. It can cause tire wear. Tire manufacturers provide the charts for deciding this pressure, however, you would need to know the weight on each tire to do this exactly right. Who would do that? Would you go to that much trouble on your car?
I vote to err on the side of caution and just pump them up to the recommendation on the yellow sticker.
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Old Yesterday, 09:48 PM   #51
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[QUOTE=Tireman9;436472


Yes almost all ST type tires have the same table numbers and the intention is for the vehicle manufacturer to use the table to select the appropriate tire and inflation for each specific application. But again that means someone at the RV Co has to stop and think about what they are doing. Actual car companies have teams of engineers doing this work while it appears the RV Co have decided the new owner can figure it out.

[/QUOTE]

I’m having a hard time getting the preceding paragraph to wash. Of course that is my point of view based on regulations and standards.

Basically, tire inflation charts are tools. They are not recommendations. They provide specific information for those that SET recommended cold inflation pressures. The information provided on load inflation charts were initially determined by the tire manufacturers. The Tire and Rim Association (TRA) has the ultimate responsibility for standardizing the inputs from tire manufacturers and produce tire inflation charts in 5 PSI increments.

It appears that the paragraph in question is praising one section of the tire industry (automotive) and belittling another (RV Trailer). Even though both industries get their tire inflating instructions from the same FMVSS standards, there are vast differences in how they are applied. For instance; the OE tires for RV trailers are installed on RV trailer axles using the vehicle GAWRs as a guide. The vehicle manufacturer has the opportunity to set those GAWR maximum loads. In the reference below, using a little math and a load inflation chart for the OE tires you can see just how slim the margin is for error – none.

Click image for larger version

Name:	1 - loading even.JPG
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ID:	32223

Inflating RV trailer OE tires to a load carried is not an acceptable standard. That method is derived from the commercial trucking industry and they operate under a completely different set of rules and standards. Besides that, who is going to load up their RV trailer and get tire loads for each tire position every time they add or subtract a hundred pounds to/from their trailer’s cargo load?

The RV industry has long needed tire inflation pressure reserves above vehicle GAWRs. All new trailers now have that reserve inflation pressure. It’s beyond me why an owner would want to decrease those load capacity reserves.

Most owners don’t realize the significance of the vehicle certification label. It provides sworn statements that the trailer adheres to all vehicle safety standards at the time it was completed. Those safety standards are minimums. That means that the tire designated size depicted on the vehicle certification label provides minimum protection at the vehicle manufacturer’s recommended cold inflation pressures.
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Old Today, 07:16 AM   #52
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What Cal just posted is a "wider vision" of what Tireman9 posted. People who "spend a career in the tire engineering business" tend to view "their aspect of the business" and lose some perspective of the other areas of design that go into the "finished product". That's not a "slam dunk" for any specific part of engineering, but rather a "reality of what happens"...

We're doing pretty much the same thing in this thread....

Take for example, two trailers that weigh the same 14000 pounds "GVWR" with 2500 pounds of pin weight, both are 38' long, but with different slide configurations and different floorplans....

Trailer 1 may be a "rear kitchen model" with the heavy appliances positioned along the rear wall, very close to centered (side to side), so there is no impact on "side balance". It may have opposing slides over the axles, roadside with a large entertainment center weighing about 300 pounds and the curb slide having theater seating weighing about 300 pounds. That trailer may very well have "nearly equal weight over all 4 tires"....

Now, take trailer #2: It may be a "center kitchen model" with a heavy, 16' "kitchen slide" on the roadside. It might have a 4 door LP/Elec refrigerator over the rear roadside tire with that same "heavy entertainment center" aft of the refrigerator and a large pantry, just forward of the refrigerator. That slide might place 1500 pounds of potential weight over the tires on that side of the trailer. Now, imagine a 12' slide on the curb side, with a light dining table and 2 chairs with 2 small recliners just aft of that, the total slide weighing 700 pounds.

When designing/engineering either trailer, a part of the design would be to weigh individual wheels and decide which tires are appropriate. One trailer may have all 4 wheels "equally balanced" and a 15% excess capacity could/be achieved with 225/80R16 LRE tires at 80PSI.

Conversely, the other trailer in this example may have the roadside tires loaded with 700 or more pounds and the rear tire on that side loaded with nearly all of that "unbalanced load"... In other words, the roadside, rear tire may be carrying 50% more weight than the opposing tire on the same axle and the roadside pair may be carrying "more than double" the excess weight that the curbside pair are carrying..... Because of that "roadside rear tire weight" this trailer may require 235/85R16 LRF tires to achieve the same 15% excess capacity, even though the other three tires may be "perfectly happy with smaller tires"....

Now, ALL tires on the same axle must be "the same size and aired to the same pressure" and for compliance, I've always seen all tires on a trailer aired to the same pressure at all tire locations.

So, even though we have, in this example, two identical weight trailers that are the same length with the same cargo capacity, they "could have" dramatically different tire loading, tire size requirements and tire pressure requirements....

For anyone to "crawl in a bubble and only look at a small part of the design and implementation" can't present the "whole picture for how one trailer can be very different than the same "outward appearance trailer" sitting next to it...

Each trailer is a unique and individual "implementation" and for us to try to "put all 14000 pound 38' trailers in the same "tire size and pressure" is just "simply impossible"... To complicate that further, when the owner's DW adds "38 pairs of shoes" to the front closet, and the "other owner of that same floorplan" is a bachelor who prefers to be barefoot" .... Well you get the idea....
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